Updated version 6.5.0 from 'upstream/6.5.0'

with Debian dir 0e7974378beb3a0e210f76683af960dea205a2e9

11 files changed, 2419 insertions, 603 deletions

diff --git a/src/oniguruma.h b/src/oniguruma.h
index a8ae09a..bc8983f 100644
--- a/src/oniguruma.h
+++ b/src/oniguruma.h
@@ -35,7 +35,7 @@ extern "C" {
 
 #define ONIGURUMA
 #define ONIGURUMA_VERSION_MAJOR   6
-#define ONIGURUMA_VERSION_MINOR   4
+#define ONIGURUMA_VERSION_MINOR   5
 #define ONIGURUMA_VERSION_TEENY   0
 
 #ifdef __cplusplus
@@ -496,6 +496,11 @@ ONIG_EXTERN OnigSyntaxType*   OnigDefaultSyntax;
 /* #define ONIG_SYN_OP2_CHAR_PROPERTY_PREFIX_IS (1U<<18) */
 #define ONIG_SYN_OP2_ESC_H_XDIGIT               (1U<<19) /* \h, \H */
 #define ONIG_SYN_OP2_INEFFECTIVE_ESCAPE         (1U<<20) /* \ */
+#define ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE       (1U<<21) /* (?(n)) (?(...)...|...) */
+#define ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP         (1U<<22) /* \K */
+#define ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE (1U<<23) /* \R \r\n else [\x0a-\x0d] */
+#define ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT  (1U<<24) /* \N (?-m:.), \O (?m:.) */
+#define ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP   (1U<<25) /* (?~...) */
 
 /* syntax (behavior) */
 #define ONIG_SYN_CONTEXT_INDEP_ANCHORS           (1U<<31) /* not implemented */
@@ -596,6 +601,9 @@ ONIG_EXTERN OnigSyntaxType*   OnigDefaultSyntax;
 #define ONIGERR_NEVER_ENDING_RECURSION                       -221
 #define ONIGERR_GROUP_NUMBER_OVER_FOR_CAPTURE_HISTORY        -222
 #define ONIGERR_INVALID_CHAR_PROPERTY_NAME                   -223
+#define ONIGERR_INVALID_IF_ELSE_SYNTAX                       -224
+#define ONIGERR_INVALID_ABSENT_GROUP_PATTERN                 -225
+#define ONIGERR_INVALID_ABSENT_GROUP_GENERATOR_PATTERN       -226
 #define ONIGERR_INVALID_CODE_POINT_VALUE                     -400
 #define ONIGERR_INVALID_WIDE_CHAR_VALUE                      -400
 #define ONIGERR_TOO_BIG_WIDE_CHAR_VALUE                      -401
diff --git a/src/regcomp.c b/src/regcomp.c
index db83739..47023cb 100644
--- a/src/regcomp.c
+++ b/src/regcomp.c
@@ -147,7 +147,7 @@ swap_node(Node* a, Node* b)
   Node c;
   c = *a; *a = *b; *b = c;
 
-  if (NODE_TYPE(a) == NODE_STR) {
+  if (NODE_TYPE(a) == NODE_STRING) {
     StrNode* sn = STR_(a);
     if (sn->capa == 0) {
       int len = sn->end - sn->s;
@@ -156,7 +156,7 @@ swap_node(Node* a, Node* b)
     }
   }
 
-  if (NODE_TYPE(b) == NODE_STR) {
+  if (NODE_TYPE(b) == NODE_STRING) {
     StrNode* sn = STR_(b);
     if (sn->capa == 0) {
       int len = sn->end - sn->s;
@@ -169,11 +169,11 @@ swap_node(Node* a, Node* b)
 static OnigLen
 distance_add(OnigLen d1, OnigLen d2)
 {
-  if (d1 == ONIG_INFINITE_DISTANCE || d2 == ONIG_INFINITE_DISTANCE)
-    return ONIG_INFINITE_DISTANCE;
+  if (d1 == INFINITE_LEN || d2 == INFINITE_LEN)
+    return INFINITE_LEN;
   else {
-    if (d1 <= ONIG_INFINITE_DISTANCE - d2) return d1 + d2;
-    else return ONIG_INFINITE_DISTANCE;
+    if (d1 <= INFINITE_LEN - d2) return d1 + d2;
+    else return INFINITE_LEN;
   }
 }
 
@@ -182,10 +182,10 @@ distance_multiply(OnigLen d, int m)
 {
   if (m == 0) return 0;
 
-  if (d < ONIG_INFINITE_DISTANCE / m)
+  if (d < INFINITE_LEN / m)
     return d * m;
   else
-    return ONIG_INFINITE_DISTANCE;
+    return INFINITE_LEN;
 }
 
 static int
@@ -230,7 +230,7 @@ onig_bbuf_init(BBuf* buf, int size)
 }
 
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 
 static int
 unset_addr_list_init(UnsetAddrList* list, int size)
@@ -271,7 +271,7 @@ unset_addr_list_add(UnsetAddrList* list, int offset, struct _Node* node)
   list->num++;
   return 0;
 }
-#endif /* USE_SUBEXP_CALL */
+#endif /* USE_CALL */
 
 
 static int
@@ -347,6 +347,24 @@ add_option(regex_t* reg, OnigOptionType option)
 }
 
 static int
+add_save_type(regex_t* reg, enum SaveType type)
+{
+  SaveType t = (SaveType )type;
+
+  BBUF_ADD(reg, &t, SIZE_SAVE_TYPE);
+  return 0;
+}
+
+static int
+add_update_var_type(regex_t* reg, enum UpdateVarType type)
+{
+  UpdateVarType t = (UpdateVarType )type;
+
+  BBUF_ADD(reg, &t, SIZE_UPDATE_VAR_TYPE);
+  return 0;
+}
+
+static int
 add_opcode_rel_addr(regex_t* reg, int opcode, int addr)
 {
   int r;
@@ -466,7 +484,7 @@ compile_tree_empty_check(Node* node, regex_t* reg, int empty_info, ScanEnv* env)
   return r;
 }
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 static int
 compile_call(CallNode* node, regex_t* reg, ScanEnv* env)
 {
@@ -545,7 +563,7 @@ compile_length_string_node(Node* node, regex_t* reg)
   if (sn->end <= sn->s)
     return 0;
 
-  ambig = NSTRING_IS_AMBIG(node);
+  ambig = NODE_STRING_IS_AMBIG(node);
 
   p = prev = sn->s;
   prev_len = enclen(enc, p);
@@ -594,7 +612,7 @@ compile_string_node(Node* node, regex_t* reg)
     return 0;
 
   end = sn->end;
-  ambig = NSTRING_IS_AMBIG(node);
+  ambig = NODE_STRING_IS_AMBIG(node);
 
   p = prev = sn->s;
   prev_len = enclen(enc, p);
@@ -767,7 +785,7 @@ compile_range_repeat_node(QuantNode* qn, int target_len, int empty_info,
   if (r != 0) return r;
 
   if (
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
       NODE_IS_IN_MULTI_ENTRY(qn) ||
 #endif
       NODE_IS_IN_REAL_REPEAT(qn)) {
@@ -893,7 +911,7 @@ compile_quantifier_node(QuantNode* qn, regex_t* reg, ScanEnv* env)
     r = compile_tree_n_times(NODE_QUANT_BODY(qn), qn->lower, reg, env);
     if (r != 0) return r;
     if (IS_NOT_NULL(qn->next_head_exact) && !CKN_ON) {
-      if (IS_MULTILINE(reg->options))
+      if (IS_MULTILINE(CTYPE_OPTION(NODE_QUANT_BODY(qn), reg)))
         r = add_opcode(reg, OP_ANYCHAR_ML_STAR_PEEK_NEXT);
       else
         r = add_opcode(reg, OP_ANYCHAR_STAR_PEEK_NEXT);
@@ -906,7 +924,7 @@ compile_quantifier_node(QuantNode* qn, regex_t* reg, ScanEnv* env)
       return add_bytes(reg, STR_(qn->next_head_exact)->s, 1);
     }
     else {
-      if (IS_MULTILINE(reg->options)) {
+      if (IS_MULTILINE(CTYPE_OPTION(NODE_QUANT_BODY(qn), reg))) {
         r = add_opcode(reg, (CKN_ON ?
                              OP_STATE_CHECK_ANYCHAR_ML_STAR
                              : OP_ANYCHAR_ML_STAR));
@@ -1109,7 +1127,7 @@ compile_quantifier_node(QuantNode* qn, regex_t* reg, ScanEnv* env)
     r = compile_tree_n_times(NODE_QUANT_BODY(qn), qn->lower, reg, env);
     if (r != 0) return r;
     if (IS_NOT_NULL(qn->next_head_exact)) {
-      if (IS_MULTILINE(reg->options))
+      if (IS_MULTILINE(CTYPE_OPTION(NODE_QUANT_BODY(qn), reg)))
         r = add_opcode(reg, OP_ANYCHAR_ML_STAR_PEEK_NEXT);
       else
         r = add_opcode(reg, OP_ANYCHAR_STAR_PEEK_NEXT);
@@ -1117,7 +1135,7 @@ compile_quantifier_node(QuantNode* qn, regex_t* reg, ScanEnv* env)
       return add_bytes(reg, STR_(qn->next_head_exact)->s, 1);
     }
     else {
-      if (IS_MULTILINE(reg->options))
+      if (IS_MULTILINE(CTYPE_OPTION(NODE_QUANT_BODY(qn), reg)))
         return add_opcode(reg, OP_ANYCHAR_ML_STAR);
       else
         return add_opcode(reg, OP_ANYCHAR_STAR);
@@ -1229,7 +1247,7 @@ compile_length_option_node(EnclosureNode* node, regex_t* reg)
   int tlen;
   OnigOptionType prev = reg->options;
 
-  reg->options = node->o.option;
+  reg->options = node->o.options;
   tlen = compile_length_tree(NODE_ENCLOSURE_BODY(node), reg);
   reg->options = prev;
 
@@ -1249,8 +1267,8 @@ compile_option_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
   int r;
   OnigOptionType prev = reg->options;
 
-  if (IS_DYNAMIC_OPTION(prev ^ node->o.option)) {
-    r = add_opcode_option(reg, OP_SET_OPTION_PUSH, node->o.option);
+  if (IS_DYNAMIC_OPTION(prev ^ node->o.options)) {
+    r = add_opcode_option(reg, OP_SET_OPTION_PUSH, node->o.options);
     if (r != 0) return r;
     r = add_opcode_option(reg, OP_SET_OPTION, prev);
     if (r != 0) return r;
@@ -1258,11 +1276,11 @@ compile_option_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
     if (r != 0) return r;
   }
 
-  reg->options = node->o.option;
+  reg->options = node->o.options;
   r = compile_tree(NODE_ENCLOSURE_BODY(node), reg, env);
   reg->options = prev;
 
-  if (IS_DYNAMIC_OPTION(prev ^ node->o.option)) {
+  if (IS_DYNAMIC_OPTION(prev ^ node->o.options)) {
     if (r != 0) return r;
     r = add_opcode_option(reg, OP_SET_OPTION, prev);
   }
@@ -1287,7 +1305,7 @@ compile_length_enclosure_node(EnclosureNode* node, regex_t* reg)
 
   switch (node->type) {
   case ENCLOSURE_MEMORY:
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 
     if (node->m.regnum == 0 && NODE_IS_CALLED(node)) {
       len = tlen + SIZE_OP_CALL + SIZE_OP_JUMP + SIZE_OP_RETURN;
@@ -1336,6 +1354,32 @@ compile_length_enclosure_node(EnclosureNode* node, regex_t* reg)
     }
     break;
 
+  case ENCLOSURE_IF_ELSE:
+    {
+      Node* cond = NODE_ENCLOSURE_BODY(node);
+      Node* Then = node->te.Then;
+      Node* Else = node->te.Else;
+
+      len = compile_length_tree(cond, reg);
+      if (len < 0) return len;
+      len += SIZE_OP_PUSH;
+      len += SIZE_OP_PUSH_STOP_BT + SIZE_OP_POP_STOP_BT;
+
+      if (IS_NOT_NULL(Then)) {
+        tlen = compile_length_tree(Then, reg);
+        if (tlen < 0) return tlen;
+        len += tlen;
+      }
+
+      if (IS_NOT_NULL(Else)) {
+        len += SIZE_OP_JUMP;
+        tlen = compile_length_tree(Else, reg);
+        if (tlen < 0) return tlen;
+        len += tlen;
+      }
+    }
+    break;
+
   default:
     return ONIGERR_TYPE_BUG;
     break;
@@ -1352,7 +1396,7 @@ compile_enclosure_memory_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
   int r;
   int len;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   if (node->m.regnum == 0 && NODE_IS_CALLED(node)) {
     r = add_opcode(reg, OP_CALL);
     if (r != 0) return r;
@@ -1370,9 +1414,7 @@ compile_enclosure_memory_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
     r = add_opcode(reg, OP_RETURN);
     return r;
   }
-#endif
 
-#ifdef USE_SUBEXP_CALL
   if (NODE_IS_CALLED(node)) {
     r = add_opcode(reg, OP_CALL);
     if (r != 0) return r;
@@ -1404,7 +1446,7 @@ compile_enclosure_memory_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
   r = compile_tree(NODE_ENCLOSURE_BODY(node), reg, env);
   if (r != 0) return r;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   if (MEM_STATUS_AT0(reg->bt_mem_end, node->m.regnum))
     r = add_opcode(reg, (NODE_IS_RECURSION(node)
                          ? OP_MEMORY_END_PUSH_REC : OP_MEMORY_END_PUSH));
@@ -1434,14 +1476,15 @@ compile_enclosure_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
 {
   int r, len;
 
-  if (node->type == ENCLOSURE_OPTION)
-    return compile_option_node(node, reg, env);
-
   switch (node->type) {
   case ENCLOSURE_MEMORY:
     r = compile_enclosure_memory_node(node, reg, env);
     break;
 
+  case ENCLOSURE_OPTION:
+    r = compile_option_node(node, reg, env);
+    break;
+
   case ENCLOSURE_STOP_BACKTRACK:
     if (NODE_IS_STOP_BT_SIMPLE_REPEAT(node)) {
       QuantNode* qn = QUANT_(NODE_ENCLOSURE_BODY(node));
@@ -1469,6 +1512,49 @@ compile_enclosure_node(EnclosureNode* node, regex_t* reg, ScanEnv* env)
     }
     break;
 
+  case ENCLOSURE_IF_ELSE:
+    {
+      int cond_len, then_len, jump_len;
+      Node* cond = NODE_ENCLOSURE_BODY(node);
+      Node* Then = node->te.Then;
+      Node* Else = node->te.Else;
+
+      r = add_opcode(reg, OP_PUSH_STOP_BT);
+      if (r != 0) return r;
+
+      cond_len = compile_length_tree(cond, reg);
+      if (cond_len < 0) return cond_len;
+      if (IS_NOT_NULL(Then)) {
+        then_len = compile_length_tree(Then, reg);
+        if (then_len < 0) return then_len;
+      }
+      else
+        then_len = 0;
+
+      jump_len = cond_len + then_len + SIZE_OP_POP_STOP_BT;
+      if (IS_NOT_NULL(Else)) jump_len += SIZE_OP_JUMP;
+
+      r = add_opcode_rel_addr(reg, OP_PUSH, jump_len);
+      if (r != 0) return r;
+      r = compile_tree(cond, reg, env);
+      if (r != 0) return r;
+      r = add_opcode(reg, OP_POP_STOP_BT);
+      if (r != 0) return r;
+
+      if (IS_NOT_NULL(Then)) {
+        r = compile_tree(Then, reg, env);
+        if (r != 0) return r;
+      }
+
+      if (IS_NOT_NULL(Else)) {
+        int else_len = compile_length_tree(Else, reg);
+        r = add_opcode_rel_addr(reg, OP_JUMP, else_len);
+        if (r != 0) return r;
+        r = compile_tree(Else, reg, env);
+      }
+    }
+    break;
+
   default:
     return ONIGERR_TYPE_BUG;
     break;
@@ -1490,10 +1576,10 @@ compile_length_anchor_node(AnchorNode* node, regex_t* reg)
 
   switch (node->type) {
   case ANCHOR_PREC_READ:
-    len = SIZE_OP_PUSH_POS + tlen + SIZE_OP_POP_POS;
+    len = SIZE_OP_PREC_READ_START + tlen + SIZE_OP_PREC_READ_END;
     break;
   case ANCHOR_PREC_READ_NOT:
-    len = SIZE_OP_PUSH_POS_NOT + tlen + SIZE_OP_FAIL_POS;
+    len = SIZE_OP_PUSH_PREC_READ_NOT + tlen + SIZE_OP_FAIL_PREC_READ_NOT;
     break;
   case ANCHOR_LOOK_BEHIND:
     len = SIZE_OP_LOOK_BEHIND + tlen;
@@ -1531,21 +1617,21 @@ compile_anchor_node(AnchorNode* node, regex_t* reg, ScanEnv* env)
 #endif
 
   case ANCHOR_PREC_READ:
-    r = add_opcode(reg, OP_PUSH_POS);
+    r = add_opcode(reg, OP_PREC_READ_START);
     if (r != 0) return r;
     r = compile_tree(NODE_ANCHOR_BODY(node), reg, env);
     if (r != 0) return r;
-    r = add_opcode(reg, OP_POP_POS);
+    r = add_opcode(reg, OP_PREC_READ_END);
     break;
 
   case ANCHOR_PREC_READ_NOT:
     len = compile_length_tree(NODE_ANCHOR_BODY(node), reg);
     if (len < 0) return len;
-    r = add_opcode_rel_addr(reg, OP_PUSH_POS_NOT, len + SIZE_OP_FAIL_POS);
+    r = add_opcode_rel_addr(reg, OP_PUSH_PREC_READ_NOT, len + SIZE_OP_FAIL_PREC_READ_NOT);
     if (r != 0) return r;
     r = compile_tree(NODE_ANCHOR_BODY(node), reg, env);
     if (r != 0) return r;
-    r = add_opcode(reg, OP_FAIL_POS);
+    r = add_opcode(reg, OP_FAIL_PREC_READ_NOT);
     break;
 
   case ANCHOR_LOOK_BEHIND:
@@ -1596,6 +1682,67 @@ compile_anchor_node(AnchorNode* node, regex_t* reg, ScanEnv* env)
 }
 
 static int
+compile_gimmick_node(GimmickNode* node, regex_t* reg)
+{
+  int r;
+
+  switch (node->type) {
+  case GIMMICK_FAIL:
+    r = add_opcode(reg, OP_FAIL);
+    break;
+
+  case GIMMICK_KEEP:
+    r = add_opcode(reg, OP_PUSH_SAVE_VAL);
+    if (r != 0) return r;
+    r = add_save_type(reg, SAVE_KEEP);
+    if (r != 0) return r;
+    r = add_mem_num(reg, node->id);
+    break;
+
+  case GIMMICK_SAVE:
+    r = add_opcode(reg, OP_PUSH_SAVE_VAL);
+    if (r != 0) return r;
+    r = add_save_type(reg, node->detail_type);
+    if (r != 0) return r;
+    r = add_mem_num(reg, node->id);
+    break;
+
+  case GIMMICK_UPDATE_VAR:
+    r = add_opcode(reg, OP_UPDATE_VAR);
+    if (r != 0) return r;
+    r = add_update_var_type(reg, node->detail_type);
+    if (r != 0) return r;
+    r = add_mem_num(reg, node->id);
+    break;
+  }
+
+  return r;
+}
+
+static int
+compile_length_gimmick_node(GimmickNode* node, regex_t* reg)
+{
+  int len;
+
+  switch (node->type) {
+  case GIMMICK_FAIL:
+    len = SIZE_OP_FAIL;
+    break;
+
+  case GIMMICK_KEEP:
+  case GIMMICK_SAVE:
+    len = SIZE_OP_PUSH_SAVE_VAL;
+    break;
+
+  case GIMMICK_UPDATE_VAR:
+    len = SIZE_OP_UPDATE_VAR;
+    break;
+  }
+
+  return len;
+}
+
+static int
 compile_length_tree(Node* node, regex_t* reg)
 {
   int len, r;
@@ -1624,8 +1771,8 @@ compile_length_tree(Node* node, regex_t* reg)
     }
     break;
 
-  case NODE_STR:
-    if (NSTRING_IS_RAW(node))
+  case NODE_STRING:
+    if (NODE_STRING_IS_RAW(node))
       r = compile_length_string_raw_node(STR_(node), reg);
     else
       r = compile_length_string_node(node, reg);
@@ -1639,28 +1786,39 @@ compile_length_tree(Node* node, regex_t* reg)
     r = SIZE_OPCODE;
     break;
 
-  case NODE_BREF:
+  case NODE_BACKREF:
     {
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
 
+      if (NODE_IS_CHECKER(node)) {
 #ifdef USE_BACKREF_WITH_LEVEL
-      if (NODE_IS_NEST_LEVEL(node)) {
-        r = SIZE_OPCODE + SIZE_OPTION + SIZE_LENGTH +
-            SIZE_LENGTH + (SIZE_MEMNUM * br->back_num);
-      }
-      else
+        if (NODE_IS_NEST_LEVEL(node)) {
+          r = SIZE_OPCODE + SIZE_LENGTH + SIZE_LENGTH + (SIZE_MEMNUM * br->back_num);
+        }
+        else
 #endif
-      if (br->back_num == 1) {
-        r = ((!IS_IGNORECASE(reg->options) && br->back_static[0] <= 2)
-             ? SIZE_OPCODE : (SIZE_OPCODE + SIZE_MEMNUM));
+          r = SIZE_OPCODE + SIZE_LENGTH + (SIZE_MEMNUM * br->back_num);
       }
       else {
-        r = SIZE_OPCODE + SIZE_LENGTH + (SIZE_MEMNUM * br->back_num);
+#ifdef USE_BACKREF_WITH_LEVEL
+        if (NODE_IS_NEST_LEVEL(node)) {
+          r = SIZE_OPCODE + SIZE_OPTION + SIZE_LENGTH +
+            SIZE_LENGTH + (SIZE_MEMNUM * br->back_num);
+        }
+        else
+#endif
+        if (br->back_num == 1) {
+          r = ((!IS_IGNORECASE(reg->options) && br->back_static[0] <= 2)
+               ? SIZE_OPCODE : (SIZE_OPCODE + SIZE_MEMNUM));
+        }
+        else {
+          r = SIZE_OPCODE + SIZE_LENGTH + (SIZE_MEMNUM * br->back_num);
+        }
       }
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     r = SIZE_OP_CALL;
     break;
@@ -1678,6 +1836,10 @@ compile_length_tree(Node* node, regex_t* reg)
     r = compile_length_anchor_node(ANCHOR_(node), reg);
     break;
 
+  case NODE_GIMMICK:
+    r = compile_length_gimmick_node(GIMMICK_(node), reg);
+    break;
+
   default:
     return ONIGERR_TYPE_BUG;
     break;
@@ -1713,7 +1875,8 @@ compile_tree(Node* node, regex_t* reg, ScanEnv* env)
       do {
         len = compile_length_tree(NODE_CAR(node), reg);
         if (IS_NOT_NULL(NODE_CDR(node))) {
-          r = add_opcode_rel_addr(reg, OP_PUSH, len + SIZE_OP_JUMP);
+          enum OpCode push = NODE_IS_SUPER(node) ? OP_PUSH_SUPER : OP_PUSH;
+          r = add_opcode_rel_addr(reg, push, len + SIZE_OP_JUMP);
           if (r != 0) break;
         }
         r = compile_tree(NODE_CAR(node), reg, env);
@@ -1727,8 +1890,8 @@ compile_tree(Node* node, regex_t* reg, ScanEnv* env)
     }
     break;
 
-  case NODE_STR:
-    if (NSTRING_IS_RAW(node))
+  case NODE_STRING:
+    if (NODE_STRING_IS_RAW(node))
       r = compile_string_raw_node(STR_(node), reg);
     else
       r = compile_string_node(node, reg);
@@ -1744,7 +1907,7 @@ compile_tree(Node* node, regex_t* reg, ScanEnv* env)
 
       switch (CTYPE_(node)->ctype) {
       case CTYPE_ANYCHAR:
-        if (IS_MULTILINE(reg->options))
+        if (IS_MULTILINE(CTYPE_OPTION(node, reg)))
           r = add_opcode(reg, OP_ANYCHAR_ML);
         else
           r = add_opcode(reg, OP_ANYCHAR);
@@ -1764,69 +1927,86 @@ compile_tree(Node* node, regex_t* reg, ScanEnv* env)
     }
     break;
 
-  case NODE_BREF:
+  case NODE_BACKREF:
     {
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
 
+      if (NODE_IS_CHECKER(node)) {
 #ifdef USE_BACKREF_WITH_LEVEL
-      if (NODE_IS_NEST_LEVEL(node)) {
-        r = add_opcode(reg, OP_BACKREF_WITH_LEVEL);
-        if (r != 0) return r;
-        r = add_option(reg, (reg->options & ONIG_OPTION_IGNORECASE));
-        if (r != 0) return r;
-        r = add_length(reg, br->nest_level);
-        if (r != 0) return r;
+        if (NODE_IS_NEST_LEVEL(node)) {
+          r = add_opcode(reg, OP_BACKREF_CHECK_WITH_LEVEL);
+          if (r != 0) return r;
+          r = add_length(reg, br->nest_level);
+          if (r != 0) return r;
+        }
+        else
+#endif
+          {
+            r = add_opcode(reg, OP_BACKREF_CHECK);
+            if (r != 0) return r;
+          }
 
         goto add_bacref_mems;
       }
-      else
-#endif
-      if (br->back_num == 1) {
-        n = br->back_static[0];
-        if (IS_IGNORECASE(reg->options)) {
-          r = add_opcode(reg, OP_BACKREFN_IC);
+      else {
+#ifdef USE_BACKREF_WITH_LEVEL
+        if (NODE_IS_NEST_LEVEL(node)) {
+          r = add_opcode(reg, OP_BACKREF_WITH_LEVEL);
+          if (r != 0) return r;
+          r = add_option(reg, (reg->options & ONIG_OPTION_IGNORECASE));
+          if (r != 0) return r;
+          r = add_length(reg, br->nest_level);
           if (r != 0) return r;
-          r = add_mem_num(reg, n);
+
+          goto add_bacref_mems;
         }
-        else {
-          switch (n) {
-          case 1:  r = add_opcode(reg, OP_BACKREF1); break;
-          case 2:  r = add_opcode(reg, OP_BACKREF2); break;
-          default:
-            r = add_opcode(reg, OP_BACKREFN);
+        else
+#endif
+        if (br->back_num == 1) {
+          n = br->back_static[0];
+          if (IS_IGNORECASE(reg->options)) {
+            r = add_opcode(reg, OP_BACKREF_N_IC);
             if (r != 0) return r;
             r = add_mem_num(reg, n);
-            break;
           }
-        }
-      }
-      else {
-        int i;
-        int* p;
-
-        if (IS_IGNORECASE(reg->options)) {
-          r = add_opcode(reg, OP_BACKREF_MULTI_IC);
+          else {
+            switch (n) {
+            case 1:  r = add_opcode(reg, OP_BACKREF1); break;
+            case 2:  r = add_opcode(reg, OP_BACKREF2); break;
+            default:
+              r = add_opcode(reg, OP_BACKREF_N);
+              if (r != 0) return r;
+              r = add_mem_num(reg, n);
+              break;
+            }
+          }
         }
         else {
-          r = add_opcode(reg, OP_BACKREF_MULTI);
-        }
-        if (r != 0) return r;
+          int i;
+          int* p;
 
-#ifdef USE_BACKREF_WITH_LEVEL
-      add_bacref_mems:
-#endif
-        r = add_length(reg, br->back_num);
-        if (r != 0) return r;
-        p = BACKREFS_P(br);
-        for (i = br->back_num - 1; i >= 0; i--) {
-          r = add_mem_num(reg, p[i]);
+          if (IS_IGNORECASE(reg->options)) {
+            r = add_opcode(reg, OP_BACKREF_MULTI_IC);
+          }
+          else {
+            r = add_opcode(reg, OP_BACKREF_MULTI);
+          }
           if (r != 0) return r;
+
+        add_bacref_mems:
+          r = add_length(reg, br->back_num);
+          if (r != 0) return r;
+          p = BACKREFS_P(br);
+          for (i = br->back_num - 1; i >= 0; i--) {
+            r = add_mem_num(reg, p[i]);
+            if (r != 0) return r;
+          }
         }
       }
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     r = compile_call(CALL_(node), reg, env);
     break;
@@ -1844,6 +2024,10 @@ compile_tree(Node* node, regex_t* reg, ScanEnv* env)
     r = compile_anchor_node(ANCHOR_(node), reg, env);
     break;
 
+  case NODE_GIMMICK:
+    r = compile_gimmick_node(GIMMICK_(node), reg);
+    break;
+
   default:
 #ifdef ONIG_DEBUG
     fprintf(stderr, "compile_tree: undefined node type %d\n", NODE_TYPE(node));
@@ -1898,6 +2082,18 @@ noname_disable_map(Node** plink, GroupNumRemap* map, int* counter)
           r = noname_disable_map(plink, map, counter);
         }
       }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        r = noname_disable_map(&(NODE_ENCLOSURE_BODY(en)), map, counter);
+        if (r != 0) return r;
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = noname_disable_map(&(en->te.Then), map, counter);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r = noname_disable_map(&(en->te.Else), map, counter);
+          if (r != 0) return r;
+        }
+      }
       else
         r = noname_disable_map(&(NODE_BODY(node)), map, counter);
     }
@@ -1920,7 +2116,7 @@ renumber_node_backref(Node* node, GroupNumRemap* map)
 {
   int i, pos, n, old_num;
   int *backs;
-  BRefNode* bn = BREF_(node);
+  BackRefNode* bn = BACKREF_(node);
 
   if (! NODE_IS_BY_NAME(node))
     return ONIGERR_NUMBERED_BACKREF_OR_CALL_NOT_ALLOWED;
@@ -1957,11 +2153,29 @@ renumber_by_map(Node* node, GroupNumRemap* map)
     break;
 
   case NODE_QUANT:
-  case NODE_ENCLOSURE:
     r = renumber_by_map(NODE_BODY(node), map);
     break;
 
-  case NODE_BREF:
+  case NODE_ENCLOSURE:
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+      r = renumber_by_map(NODE_BODY(node), map);
+      if (r != 0) return r;
+
+      if (en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = renumber_by_map(en->te.Then, map);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r = renumber_by_map(en->te.Else, map);
+          if (r != 0) return r;
+        }
+      }
+    }
+    break;
+
+  case NODE_BACKREF:
     r = renumber_node_backref(node, map);
     break;
 
@@ -1995,11 +2209,30 @@ numbered_ref_check(Node* node)
       break;
     /* fall */
   case NODE_QUANT:
-  case NODE_ENCLOSURE:
     r = numbered_ref_check(NODE_BODY(node));
     break;
 
-  case NODE_BREF:
+  case NODE_ENCLOSURE:
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+      r = numbered_ref_check(NODE_BODY(node));
+      if (r != 0) return r;
+
+      if (en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = numbered_ref_check(en->te.Then);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r = numbered_ref_check(en->te.Else);
+          if (r != 0) return r;
+        }
+      }
+    }
+
+    break;
+
+  case NODE_BACKREF:
     if (! NODE_IS_BY_NAME(node))
       return ONIGERR_NUMBERED_BACKREF_OR_CALL_NOT_ALLOWED;
     break;
@@ -2052,7 +2285,7 @@ disable_noname_group_capture(Node** root, regex_t* reg, ScanEnv* env)
 }
 #endif /* USE_NAMED_GROUP */
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 static int
 unset_addr_list_fix(UnsetAddrList* uslist, regex_t* reg)
 {
@@ -2061,9 +2294,11 @@ unset_addr_list_fix(UnsetAddrList* uslist, regex_t* reg)
   AbsAddrType addr;
 
   for (i = 0; i < uslist->num; i++) {
+    if (! NODE_IS_ADDR_FIXED(uslist->us[i].target))
+      return ONIGERR_PARSER_BUG;
+
     en = ENCLOSURE_(uslist->us[i].target);
-    if (! NODE_IS_ADDR_FIXED(en)) return ONIGERR_PARSER_BUG;
-    addr = en->m.called_addr;
+    addr   = en->m.called_addr;
     offset = uslist->us[i].offset;
 
     BBUF_WRITE(reg, offset, &addr, SIZE_ABSADDR);
@@ -2120,7 +2355,7 @@ get_char_length_tree1(Node* node, regex_t* reg, int* len, int level)
     }
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     {
       StrNode* sn = STR_(node);
       UChar *s = sn->s;
@@ -2135,16 +2370,21 @@ get_char_length_tree1(Node* node, regex_t* reg, int* len, int level)
     {
       QuantNode* qn = QUANT_(node);
       if (qn->lower == qn->upper) {
-        r = get_char_length_tree1(NODE_BODY(node), reg, &tlen, level);
-        if (r == 0)
-          *len = distance_multiply(tlen, qn->lower);
+        if (qn->upper == 0) {
+          *len = 0;
+        }
+        else {
+          r = get_char_length_tree1(NODE_BODY(node), reg, &tlen, level);
+          if (r == 0)
+            *len = distance_multiply(tlen, qn->lower);
+        }
       }
       else
         r = GET_CHAR_LEN_VARLEN;
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     if (! NODE_IS_RECURSION(node))
       r = get_char_length_tree1(NODE_BODY(node), reg, len, level);
@@ -2166,7 +2406,7 @@ get_char_length_tree1(Node* node, regex_t* reg, int* len, int level)
       EnclosureNode* en = ENCLOSURE_(node);
       switch (en->type) {
       case ENCLOSURE_MEMORY:
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
         if (NODE_IS_CLEN_FIXED(node))
           *len = en->char_len;
         else {
@@ -2182,6 +2422,31 @@ get_char_length_tree1(Node* node, regex_t* reg, int* len, int level)
       case ENCLOSURE_STOP_BACKTRACK:
         r = get_char_length_tree1(NODE_BODY(node), reg, len, level);
         break;
+      case ENCLOSURE_IF_ELSE:
+        {
+          int clen, elen;
+          r = get_char_length_tree1(NODE_BODY(node), reg, &clen, level);
+          if (r == 0) {
+            if (IS_NOT_NULL(en->te.Then)) {
+              r = get_char_length_tree1(en->te.Then, reg, &tlen, level);
+              if (r != 0) break;
+            }
+            else tlen = 0;
+            if (IS_NOT_NULL(en->te.Else)) {
+              r = get_char_length_tree1(en->te.Else, reg, &elen, level);
+              if (r != 0) break;
+            }
+            else elen = 0;
+
+            if (clen + tlen != elen) {
+              r = GET_CHAR_LEN_VARLEN;
+            }
+            else {
+              *len = elen;
+            }
+          }
+        }
+        break;
       default:
         break;
       }
@@ -2189,8 +2454,13 @@ get_char_length_tree1(Node* node, regex_t* reg, int* len, int level)
     break;
 
   case NODE_ANCHOR:
+  case NODE_GIMMICK:
     break;
 
+  case NODE_BACKREF:
+    if (NODE_IS_CHECKER(node))
+      break;
+    /* fall */
   default:
     r = GET_CHAR_LEN_VARLEN;
     break;
@@ -2241,7 +2511,7 @@ is_exclusive(Node* x, Node* y, regex_t* reg)
         }
         break;
 
-      case NODE_STR:
+      case NODE_STRING:
         goto swap;
         break;
 
@@ -2318,7 +2588,7 @@ is_exclusive(Node* x, Node* y, regex_t* reg)
         }
         break;
 
-      case NODE_STR:
+      case NODE_STRING:
         goto swap;
         break;
 
@@ -2328,10 +2598,10 @@ is_exclusive(Node* x, Node* y, regex_t* reg)
     }
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     {
       StrNode* xs = STR_(x);
-      if (NSTRING_LEN(x) == 0)
+      if (NODE_STRING_LEN(x) == 0)
         break;
 
       //c = *(xs->s);
@@ -2362,13 +2632,13 @@ is_exclusive(Node* x, Node* y, regex_t* reg)
         }
         break;
 
-      case NODE_STR:
+      case NODE_STRING:
         {
           UChar *q;
           StrNode* ys = STR_(y);
-          len = NSTRING_LEN(x);
-          if (len > NSTRING_LEN(y)) len = NSTRING_LEN(y);
-          if (NSTRING_IS_AMBIG(x) || NSTRING_IS_AMBIG(y)) {
+          len = NODE_STRING_LEN(x);
+          if (len > NODE_STRING_LEN(y)) len = NODE_STRING_LEN(y);
+          if (NODE_STRING_IS_AMBIG(x) || NODE_STRING_IS_AMBIG(y)) {
             /* tiny version */
             return 0;
           }
@@ -2399,9 +2669,9 @@ get_head_value_node(Node* node, int exact, regex_t* reg)
   Node* n = NULL_NODE;
 
   switch (NODE_TYPE(node)) {
-  case NODE_BREF:
+  case NODE_BACKREF:
   case NODE_ALT:
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
 #endif
     break;
@@ -2420,7 +2690,7 @@ get_head_value_node(Node* node, int exact, regex_t* reg)
     n = get_head_value_node(NODE_CAR(node), exact, reg);
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     {
       StrNode* sn = STR_(node);
 
@@ -2428,7 +2698,7 @@ get_head_value_node(Node* node, int exact, regex_t* reg)
         break;
 
       if (exact != 0 &&
-          !NSTRING_IS_RAW(node) && IS_IGNORECASE(reg->options)) {
+          !NODE_STRING_IS_RAW(node) && IS_IGNORECASE(reg->options)) {
       }
       else {
         n = node;
@@ -2456,7 +2726,7 @@ get_head_value_node(Node* node, int exact, regex_t* reg)
         {
           OnigOptionType options = reg->options;
 
-          reg->options = ENCLOSURE_(node)->o.option;
+          reg->options = ENCLOSURE_(node)->o.options;
           n = get_head_value_node(NODE_BODY(node), exact, reg);
           reg->options = options;
         }
@@ -2464,6 +2734,7 @@ get_head_value_node(Node* node, int exact, regex_t* reg)
 
       case ENCLOSURE_MEMORY:
       case ENCLOSURE_STOP_BACKTRACK:
+      case ENCLOSURE_IF_ELSE:
         n = get_head_value_node(NODE_BODY(node), exact, reg);
         break;
       }
@@ -2475,6 +2746,7 @@ get_head_value_node(Node* node, int exact, regex_t* reg)
       n = get_head_value_node(NODE_BODY(node), exact, reg);
     break;
 
+  case NODE_GIMMICK:
   default:
     break;
   }
@@ -2512,6 +2784,15 @@ check_type_tree(Node* node, int type_mask, int enclosure_mask, int anchor_mask)
         return 1;
 
       r = check_type_tree(NODE_BODY(node), type_mask, enclosure_mask, anchor_mask);
+      if (r == 0 && en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = check_type_tree(en->te.Then, type_mask, enclosure_mask, anchor_mask);
+          if (r != 0) break;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r = check_type_tree(en->te.Else, type_mask, enclosure_mask, anchor_mask);
+        }
+      }
     }
     break;
 
@@ -2524,6 +2805,7 @@ check_type_tree(Node* node, int type_mask, int enclosure_mask, int anchor_mask)
       r = check_type_tree(NODE_BODY(node), type_mask, enclosure_mask, anchor_mask);
     break;
 
+  case NODE_GIMMICK:
   default:
     break;
   }
@@ -2531,31 +2813,31 @@ check_type_tree(Node* node, int type_mask, int enclosure_mask, int anchor_mask)
 }
 
 static OnigLen
-get_min_len(Node* node, ScanEnv* env)
+tree_min_len(Node* node, ScanEnv* env)
 {
   OnigLen len;
   OnigLen tmin;
 
   len = 0;
   switch (NODE_TYPE(node)) {
-  case NODE_BREF:
-    {
+  case NODE_BACKREF:
+    if (! NODE_IS_CHECKER(node)) {
       int i;
       int* backs;
       MemEnv* mem_env = SCANENV_MEMENV(env);
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
       if (NODE_IS_RECURSION(node)) break;
 
       backs = BACKREFS_P(br);
-      len = get_min_len(mem_env[backs[0]].node, env);
+      len = tree_min_len(mem_env[backs[0]].node, env);
       for (i = 1; i < br->back_num; i++) {
-        tmin = get_min_len(mem_env[backs[i]].node, env);
+        tmin = tree_min_len(mem_env[backs[i]].node, env);
         if (len > tmin) len = tmin;
       }
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     {
       Node* t = NODE_BODY(node);
@@ -2564,15 +2846,15 @@ get_min_len(Node* node, ScanEnv* env)
           len = ENCLOSURE_(t)->min_len;
       }
       else
-        len = get_min_len(t, env);
+        len = tree_min_len(t, env);
     }
     break;
 #endif
 
   case NODE_LIST:
     do {
-      tmin = get_min_len(NODE_CAR(node), env);
-      len += tmin;
+      tmin = tree_min_len(NODE_CAR(node), env);
+      len = distance_add(len, tmin);
     } while (IS_NOT_NULL(node = NODE_CDR(node)));
     break;
 
@@ -2582,14 +2864,14 @@ get_min_len(Node* node, ScanEnv* env)
       y = node;
       do {
         x = NODE_CAR(y);
-        tmin = get_min_len(x, env);
+        tmin = tree_min_len(x, env);
         if (y == node) len = tmin;
         else if (len > tmin) len = tmin;
       } while (IS_NOT_NULL(y = NODE_CDR(y)));
     }
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     {
       StrNode* sn = STR_(node);
       len = sn->end - sn->s;
@@ -2598,7 +2880,7 @@ get_min_len(Node* node, ScanEnv* env)
 
   case NODE_CTYPE:
   case NODE_CCLASS:
-    len = 1;
+    len = ONIGENC_MBC_MINLEN(env->enc);
     break;
 
   case NODE_QUANT:
@@ -2606,7 +2888,7 @@ get_min_len(Node* node, ScanEnv* env)
       QuantNode* qn = QUANT_(node);
 
       if (qn->lower > 0) {
-        len = get_min_len(NODE_BODY(node), env);
+        len = tree_min_len(NODE_BODY(node), env);
         len = distance_multiply(len, qn->lower);
       }
     }
@@ -2624,7 +2906,7 @@ get_min_len(Node* node, ScanEnv* env)
             len = 0;  // recursive
           else {
             NODE_STATUS_ADD(node, NST_MARK1);
-            len = get_min_len(NODE_BODY(node), env);
+            len = tree_min_len(NODE_BODY(node), env);
             NODE_STATUS_REMOVE(node, NST_MARK1);
 
             en->min_len = len;
@@ -2635,12 +2917,34 @@ get_min_len(Node* node, ScanEnv* env)
 
       case ENCLOSURE_OPTION:
       case ENCLOSURE_STOP_BACKTRACK:
-        len = get_min_len(NODE_BODY(node), env);
+        len = tree_min_len(NODE_BODY(node), env);
+        break;
+      case ENCLOSURE_IF_ELSE:
+        {
+          int elen;
+          len = tree_min_len(NODE_BODY(node), env);
+          if (IS_NOT_NULL(en->te.Then))
+            len += tree_min_len(en->te.Then, env);
+          if (IS_NOT_NULL(en->te.Else))
+            elen = tree_min_len(en->te.Else, env);
+          else elen = 0;
+
+          if (elen < len) len = elen;
+        }
         break;
       }
     }
     break;
 
+  case NODE_GIMMICK:
+    {
+      GimmickNode* g = GIMMICK_(node);
+      if (g->type == GIMMICK_FAIL) {
+        len = INFINITE_LEN;
+        break;
+      }
+    }
+    /* fall */
   case NODE_ANCHOR:
   default:
     break;
@@ -2650,7 +2954,7 @@ get_min_len(Node* node, ScanEnv* env)
 }
 
 static OnigLen
-get_max_len(Node* node, ScanEnv* env)
+tree_max_len(Node* node, ScanEnv* env)
 {
   OnigLen len;
   OnigLen tmax;
@@ -2659,19 +2963,19 @@ get_max_len(Node* node, ScanEnv* env)
   switch (NODE_TYPE(node)) {
   case NODE_LIST:
     do {
-      tmax = get_max_len(NODE_CAR(node), env);
+      tmax = tree_max_len(NODE_CAR(node), env);
       len = distance_add(len, tmax);
     } while (IS_NOT_NULL(node = NODE_CDR(node)));
     break;
 
   case NODE_ALT:
     do {
-      tmax = get_max_len(NODE_CAR(node), env);
+      tmax = tree_max_len(NODE_CAR(node), env);
       if (len < tmax) len = tmax;
     } while (IS_NOT_NULL(node = NODE_CDR(node)));
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     {
       StrNode* sn = STR_(node);
       len = sn->end - sn->s;
@@ -2683,30 +2987,30 @@ get_max_len(Node* node, ScanEnv* env)
     len = ONIGENC_MBC_MAXLEN_DIST(env->enc);
     break;
 
-  case NODE_BREF:
-    {
+  case NODE_BACKREF:
+    if (! NODE_IS_CHECKER(node)) {
       int i;
       int* backs;
       MemEnv* mem_env = SCANENV_MEMENV(env);
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
       if (NODE_IS_RECURSION(node)) {
-        len = ONIG_INFINITE_DISTANCE;
+        len = INFINITE_LEN;
         break;
       }
       backs = BACKREFS_P(br);
       for (i = 0; i < br->back_num; i++) {
-        tmax = get_max_len(mem_env[backs[i]].node, env);
+        tmax = tree_max_len(mem_env[backs[i]].node, env);
         if (len < tmax) len = tmax;
       }
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     if (! NODE_IS_RECURSION(node))
-      len = get_max_len(NODE_BODY(node), env);
+      len = tree_max_len(NODE_BODY(node), env);
     else
-      len = ONIG_INFINITE_DISTANCE;
+      len = INFINITE_LEN;
     break;
 #endif
 
@@ -2715,12 +3019,12 @@ get_max_len(Node* node, ScanEnv* env)
       QuantNode* qn = QUANT_(node);
 
       if (qn->upper != 0) {
-        len = get_max_len(NODE_BODY(node), env);
+        len = tree_max_len(NODE_BODY(node), env);
         if (len != 0) {
           if (! IS_REPEAT_INFINITE(qn->upper))
             len = distance_multiply(len, qn->upper);
           else
-            len = ONIG_INFINITE_DISTANCE;
+            len = INFINITE_LEN;
         }
       }
     }
@@ -2735,10 +3039,10 @@ get_max_len(Node* node, ScanEnv* env)
           len = en->max_len;
         else {
           if (NODE_IS_MARK1(node))
-            len = ONIG_INFINITE_DISTANCE;
+            len = INFINITE_LEN;
           else {
             NODE_STATUS_ADD(node, NST_MARK1);
-            len = get_max_len(NODE_BODY(node), env);
+            len = tree_max_len(NODE_BODY(node), env);
             NODE_STATUS_REMOVE(node, NST_MARK1);
 
             en->max_len = len;
@@ -2749,13 +3053,29 @@ get_max_len(Node* node, ScanEnv* env)
 
       case ENCLOSURE_OPTION:
       case ENCLOSURE_STOP_BACKTRACK:
-        len = get_max_len(NODE_BODY(node), env);
+        len = tree_max_len(NODE_BODY(node), env);
+        break;
+      case ENCLOSURE_IF_ELSE:
+        {
+          int tlen, elen;
+          len = tree_max_len(NODE_BODY(node), env);
+          if (IS_NOT_NULL(en->te.Then)) {
+            tlen = tree_max_len(en->te.Then, env);
+            len = distance_add(len, tlen);
+          }
+          if (IS_NOT_NULL(en->te.Else))
+            elen = tree_max_len(en->te.Else, env);
+          else elen = 0;
+
+          if (elen > len) len = elen;
+        }
         break;
       }
     }
     break;
 
   case NODE_ANCHOR:
+  case NODE_GIMMICK:
   default:
     break;
   }
@@ -2783,14 +3103,31 @@ check_backrefs(Node* node, ScanEnv* env)
     }
     /* fall */
   case NODE_QUANT:
+    r = check_backrefs(NODE_BODY(node), env);
+    break;
+
   case NODE_ENCLOSURE:
     r = check_backrefs(NODE_BODY(node), env);
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+
+      if (en->type == ENCLOSURE_IF_ELSE) {
+        if (r != 0) return r;
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = check_backrefs(en->te.Then, env);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r = check_backrefs(en->te.Else, env);
+        }
+      }
+    }
     break;
 
-  case NODE_BREF:
+  case NODE_BACKREF:
     {
       int i;
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
       int* backs = BACKREFS_P(br);
       MemEnv* mem_env = SCANENV_MEMENV(env);
 
@@ -2813,7 +3150,7 @@ check_backrefs(Node* node, ScanEnv* env)
 }
 
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 
 #define RECURSION_EXIST        (1<<0)
 #define RECURSION_MUST         (1<<1)
@@ -2822,6 +3159,7 @@ check_backrefs(Node* node, ScanEnv* env)
 static int
 infinite_recursive_call_check(Node* node, ScanEnv* env, int head)
 {
+  int ret;
   int r = 0;
 
   switch (NODE_TYPE(node)) {
@@ -2829,15 +3167,14 @@ infinite_recursive_call_check(Node* node, ScanEnv* env, int head)
     {
       Node *x;
       OnigLen min;
-      int ret;
 
       x = node;
       do {
         ret = infinite_recursive_call_check(NODE_CAR(x), env, head);
         if (ret < 0 || (ret & RECURSION_INFINITE) != 0) return ret;
         r |= ret;
-        if (head) {
-          min = get_min_len(NODE_CAR(x), env);
+        if (head != 0) {
+          min = tree_min_len(NODE_CAR(x), env);
           if (min != 0) head = 0;
         }
       } while (IS_NOT_NULL(x = NODE_CDR(x)));
@@ -2846,7 +3183,6 @@ infinite_recursive_call_check(Node* node, ScanEnv* env, int head)
 
   case NODE_ALT:
     {
-      int ret;
       int must;
 
       must = RECURSION_MUST;
@@ -2894,6 +3230,31 @@ infinite_recursive_call_check(Node* node, ScanEnv* env, int head)
           NODE_STATUS_REMOVE(node, NST_MARK2);
         }
       }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        int eret;
+
+        ret = infinite_recursive_call_check(NODE_BODY(node), env, head);
+        if (ret < 0 || (ret & RECURSION_INFINITE) != 0) return ret;
+        r |= ret;
+        if (IS_NOT_NULL(en->te.Then)) {
+          OnigLen min;
+          if (head != 0) {
+            min = tree_min_len(NODE_BODY(node), env);
+          }
+          else min = 0;
+
+          ret = infinite_recursive_call_check(en->te.Then, env, min != 0 ? 0:head);
+          if (ret < 0 || (ret & RECURSION_INFINITE) != 0) return ret;
+          r |= ret;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          eret = infinite_recursive_call_check(en->te.Else, env, head);
+          if (eret < 0 || (eret & RECURSION_INFINITE) != 0) return eret;
+          r |= (eret & RECURSION_EXIST);
+          if ((eret & RECURSION_MUST) == 0)
+            r &= ~RECURSION_MUST;
+        }
+      }
       else {
         r = infinite_recursive_call_check(NODE_BODY(node), env, head);
       }
@@ -2948,6 +3309,16 @@ infinite_recursive_call_check_trav(Node* node, ScanEnv* env)
           NODE_STATUS_REMOVE(node, NST_MARK1);
         }
       }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = infinite_recursive_call_check_trav(en->te.Then, env);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r = infinite_recursive_call_check_trav(en->te.Else, env);
+          if (r != 0) return r;
+        }
+      }
     }
 
     r = infinite_recursive_call_check_trav(NODE_BODY(node), env);
@@ -2987,7 +3358,10 @@ recursive_call_check(Node* node)
 
   case NODE_CALL:
     r = recursive_call_check(NODE_BODY(node));
-    if (r != 0) NODE_STATUS_ADD(node, NST_RECURSION);
+    if (r != 0) {
+      if (NODE_IS_MARK1(NODE_BODY(node)))
+        NODE_STATUS_ADD(node, NST_RECURSION);
+    }
     break;
 
   case NODE_ENCLOSURE:
@@ -3005,6 +3379,16 @@ recursive_call_check(Node* node)
           NODE_STATUS_REMOVE(node, NST_MARK2);
         }
       }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        r = 0;
+        if (IS_NOT_NULL(en->te.Then)) {
+          r |= recursive_call_check(en->te.Then);
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          r |= recursive_call_check(en->te.Else);
+        }
+        r |= recursive_call_check(NODE_BODY(node));
+      }
       else {
         r = recursive_call_check(NODE_BODY(node));
       }
@@ -3058,6 +3442,8 @@ recursive_call_check_trav(Node* node, ScanEnv* env, int state)
 
   case NODE_ENCLOSURE:
     {
+      int ret;
+      int state1;
       EnclosureNode* en = ENCLOSURE_(node);
 
       if (en->type == ENCLOSURE_MEMORY) {
@@ -3075,16 +3461,25 @@ recursive_call_check_trav(Node* node, ScanEnv* env, int state)
         }
       }
 
-      {
-        int ret;
-        int state1 = state;
+      state1 = state;
+      if (NODE_IS_RECURSION(node))
+        state1 |= IN_RECURSION;
 
-        if (NODE_IS_RECURSION(node))
-          state1 |= IN_RECURSION;
+      ret = recursive_call_check_trav(NODE_BODY(node), env, state1);
+      if (ret == FOUND_CALLED_NODE)
+        r = FOUND_CALLED_NODE;
 
-        ret = recursive_call_check_trav(NODE_BODY(node), env, state1);
-        if (ret == FOUND_CALLED_NODE)
-          r = FOUND_CALLED_NODE;
+      if (en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          ret = recursive_call_check_trav(en->te.Then, env, state1);
+          if (ret == FOUND_CALLED_NODE)
+            r = FOUND_CALLED_NODE;
+        }
+        if (IS_NOT_NULL(en->te.Else)) {
+          ret = recursive_call_check_trav(en->te.Else, env, state1);
+          if (ret == FOUND_CALLED_NODE)
+            r = FOUND_CALLED_NODE;
+        }
       }
     }
     break;
@@ -3126,7 +3521,7 @@ divide_look_behind_alternatives(Node* node)
   if (anc_type == ANCHOR_LOOK_BEHIND_NOT) {
     np = node;
     do {
-      SET_NODE_TYPE(np, NODE_LIST);  /* alt -> list */
+      NODE_SET_TYPE(np, NODE_LIST);  /* alt -> list */
     } while (IS_NOT_NULL(np = NODE_CDR(np)));
   }
   return 0;
@@ -3257,8 +3652,8 @@ expand_case_fold_make_rem_string(Node** rnode, UChar *s, UChar *end,
     return r;
   }
 
-  NSTRING_SET_AMBIG(node);
-  NSTRING_SET_DONT_GET_OPT_INFO(node);
+  NODE_STRING_SET_AMBIG(node);
+  NODE_STRING_SET_DONT_GET_OPT_INFO(node);
   *rnode = node;
   return 0;
 }
@@ -3386,7 +3781,7 @@ expand_case_fold_string(Node* node, regex_t* reg)
   OnigCaseFoldCodeItem items[ONIGENC_GET_CASE_FOLD_CODES_MAX_NUM];
   StrNode* sn = STR_(node);
 
-  if (NSTRING_IS_AMBIG(node)) return 0;
+  if (NODE_STRING_IS_AMBIG(node)) return 0;
 
   start = sn->s;
   end   = sn->end;
@@ -3529,10 +3924,8 @@ setup_comb_exp_check(Node* node, int state, ScanEnv* env)
   switch (NODE_TYPE(node)) {
   case NODE_LIST:
     {
-      Node* prev = NULL_NODE;
       do {
         r = setup_comb_exp_check(NODE_CAR(node), r, env);
-        prev = NODE_CAR(node);
       } while (r >= 0 && IS_NOT_NULL(node = NODE_CDR(node)));
     }
     break;
@@ -3619,8 +4012,8 @@ setup_comb_exp_check(Node* node, int state, ScanEnv* env)
       switch (en->type) {
       case ENCLOSURE_MEMORY:
         {
-          if (env->curr_max_regnum < en->regnum)
-            env->curr_max_regnum = en->regnum;
+          if (env->curr_max_regnum < en->m.regnum)
+            env->curr_max_regnum = en->m.regnum;
 
           r = setup_comb_exp_check(NODE_ENCLOSURE_BODY(en), state, env);
         }
@@ -3633,7 +4026,7 @@ setup_comb_exp_check(Node* node, int state, ScanEnv* env)
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     if (NODE_IS_RECURSION(node))
       env->has_recursion = 1;
@@ -3668,7 +4061,7 @@ quantifiers_memory_node_info(Node* node)
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     if (NODE_IS_RECURSION(node)) {
       return QUANT_BODY_IS_EMPTY_REC; /* tiny version */
@@ -3702,17 +4095,32 @@ quantifiers_memory_node_info(Node* node)
       case ENCLOSURE_STOP_BACKTRACK:
         r = quantifiers_memory_node_info(NODE_BODY(node));
         break;
+      case ENCLOSURE_IF_ELSE:
+        {
+          int v;
+          r = quantifiers_memory_node_info(NODE_BODY(node));
+          if (IS_NOT_NULL(en->te.Then)) {
+            v = quantifiers_memory_node_info(en->te.Then);
+            if (v > r) r = v;
+          }
+          if (IS_NOT_NULL(en->te.Else)) {
+            v = quantifiers_memory_node_info(en->te.Else);
+            if (v > r) r = v;
+          }
+        }
+        break;
       default:
         break;
       }
     }
     break;
 
-  case NODE_BREF:
-  case NODE_STR:
+  case NODE_BACKREF:
+  case NODE_STRING:
   case NODE_CTYPE:
   case NODE_CCLASS:
   case NODE_ANCHOR:
+  case NODE_GIMMICK:
   default:
     break;
   }
@@ -3729,7 +4137,7 @@ quantifiers_memory_node_info(Node* node)
 #define IN_ZERO_REPEAT  (1<<4)
 #define IN_MULTI_ENTRY  (1<<5)
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 
 #ifdef __GNUC__
 __inline
@@ -3745,7 +4153,7 @@ setup_call_node_call(CallNode* cn, ScanEnv* env, int state)
 #ifdef USE_NAMED_GROUP
     if (env->num_named > 0 &&
         IS_SYNTAX_BV(env->syntax, ONIG_SYN_CAPTURE_ONLY_NAMED_GROUP) &&
-        !ONIG_IS_OPTION_ON(env->option, ONIG_OPTION_CAPTURE_GROUP)) {
+        !ONIG_IS_OPTION_ON(env->options, ONIG_OPTION_CAPTURE_GROUP)) {
       return ONIGERR_NUMBERED_BACKREF_OR_CALL_NOT_ALLOWED;
     }
 #endif
@@ -3811,10 +4219,26 @@ setup_call2_call(Node* node)
     break;
 
   case NODE_ENCLOSURE:
-    if (! NODE_IS_MARK1(node)) {
-      NODE_STATUS_ADD(node, NST_MARK1);
-      setup_call2_call(NODE_BODY(node));
-      NODE_STATUS_REMOVE(node, NST_MARK1);
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+
+      if (en->type == ENCLOSURE_MEMORY) {
+        if (! NODE_IS_MARK1(node)) {
+          NODE_STATUS_ADD(node, NST_MARK1);
+          setup_call2_call(NODE_BODY(node));
+          NODE_STATUS_REMOVE(node, NST_MARK1);
+        }
+      }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        setup_call2_call(NODE_BODY(node));
+        if (IS_NOT_NULL(en->te.Then))
+          setup_call2_call(en->te.Then);
+        if (IS_NOT_NULL(en->te.Else))
+          setup_call2_call(en->te.Else);
+      }
+      else {
+        setup_call2_call(NODE_BODY(node));
+      }
     }
     break;
 
@@ -3868,11 +4292,29 @@ setup_call(Node* node, ScanEnv* env, int state)
     break;
 
   case NODE_ENCLOSURE:
-    if ((state & IN_ZERO_REPEAT) != 0) {
-      NODE_STATUS_ADD(node, NST_IN_ZERO_REPEAT);
-      ENCLOSURE_(node)->m.entry_count--;
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+
+      if (en->type == ENCLOSURE_MEMORY) {
+        if ((state & IN_ZERO_REPEAT) != 0) {
+          NODE_STATUS_ADD(node, NST_IN_ZERO_REPEAT);
+          ENCLOSURE_(node)->m.entry_count--;
+        }
+        r = setup_call(NODE_BODY(node), env, state);
+      }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        r = setup_call(NODE_BODY(node), env, state);
+        if (r != 0) return r;
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = setup_call(en->te.Then, env, state);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else))
+          r = setup_call(en->te.Else, env, state);
+      }
+      else
+        r = setup_call(NODE_BODY(node), env, state);
     }
-    r = setup_call(NODE_BODY(node), env, state);
     break;
 
   case NODE_CALL:
@@ -3918,6 +4360,20 @@ setup_call2(Node* node)
   case NODE_ENCLOSURE:
     if (! NODE_IS_IN_ZERO_REPEAT(node))
       r = setup_call2(NODE_BODY(node));
+
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+
+      if (r != 0) return r;
+      if (en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = setup_call2(en->te.Then);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else))
+          r = setup_call2(en->te.Else);
+      }
+    }
     break;
 
   case NODE_CALL:
@@ -3997,6 +4453,13 @@ setup_called_state_call(Node* node, int state)
           NODE_STATUS_REMOVE(node, NST_MARK1);
         }
       }
+      else if (en->type == ENCLOSURE_IF_ELSE) {
+        if (IS_NOT_NULL(en->te.Then)) {
+          setup_called_state_call(en->te.Then, state);
+        }
+        if (IS_NOT_NULL(en->te.Else))
+          setup_called_state_call(en->te.Else, state);
+      }
       else {
         setup_called_state_call(NODE_BODY(node), state);
       }
@@ -4025,7 +4488,7 @@ setup_called_state(Node* node, int state)
     } while (IS_NOT_NULL(node = NODE_CDR(node)));
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     setup_called_state_call(node, state);
     break;
@@ -4046,6 +4509,13 @@ setup_called_state(Node* node, int state)
       case ENCLOSURE_STOP_BACKTRACK:
         setup_called_state(NODE_BODY(node), state);
         break;
+      case ENCLOSURE_IF_ELSE:
+        setup_called_state(NODE_BODY(node), state);
+        if (IS_NOT_NULL(en->te.Then))
+          setup_called_state(en->te.Then, state);
+        if (IS_NOT_NULL(en->te.Else))
+          setup_called_state(en->te.Else, state);
+        break;
       }
     }
     break;
@@ -4082,16 +4552,17 @@ setup_called_state(Node* node, int state)
     }
     break;
 
-  case NODE_BREF:
-  case NODE_STR:
+  case NODE_BACKREF:
+  case NODE_STRING:
   case NODE_CTYPE:
   case NODE_CCLASS:
+  case NODE_GIMMICK:
   default:
     break;
   }
 }
 
-#endif  /* USE_SUBEXP_CALL */
+#endif  /* USE_CALL */
 
 
 static int setup_tree(Node* node, regex_t* reg, int state, ScanEnv* env);
@@ -4104,8 +4575,9 @@ setup_anchor(Node* node, regex_t* reg, int state, ScanEnv* env)
 {
 /* allowed node types in look-behind */
 #define ALLOWED_TYPE_IN_LB \
-  ( BIT_NODE_LIST | BIT_NODE_ALT | BIT_NODE_STR | BIT_NODE_CCLASS | BIT_NODE_CTYPE \
-  | BIT_NODE_ANCHOR | BIT_NODE_ENCLOSURE | BIT_NODE_QUANT | BIT_NODE_CALL )
+  ( BIT_NODE_LIST | BIT_NODE_ALT | BIT_NODE_STRING | BIT_NODE_CCLASS \
+  | BIT_NODE_CTYPE | BIT_NODE_ANCHOR | BIT_NODE_ENCLOSURE | BIT_NODE_QUANT \
+  | BIT_NODE_CALL )
 
 #define ALLOWED_ENCLOSURE_IN_LB       ( ENCLOSURE_MEMORY | ENCLOSURE_OPTION )
 #define ALLOWED_ENCLOSURE_IN_LB_NOT   ENCLOSURE_OPTION
@@ -4182,7 +4654,7 @@ setup_quant(Node* node, regex_t* reg, int state, ScanEnv* env)
   }
 
   if (IS_REPEAT_INFINITE(qn->upper) || qn->upper >= 1) {
-    d = get_min_len(body, env);
+    d = tree_min_len(body, env);
     if (d == 0) {
 #ifdef USE_INSISTENT_CHECK_CAPTURES_STATUS_IN_ENDLESS_REPEAT
       qn->body_empty_info = quantifiers_memory_node_info(body);
@@ -4208,10 +4680,10 @@ setup_quant(Node* node, regex_t* reg, int state, ScanEnv* env)
 
   /* expand string */
 #define EXPAND_STRING_MAX_LENGTH  100
-  if (NODE_TYPE(body) == NODE_STR) {
+  if (NODE_TYPE(body) == NODE_STRING) {
     if (!IS_REPEAT_INFINITE(qn->lower) && qn->lower == qn->upper &&
         qn->lower > 1 && qn->lower <= EXPAND_STRING_MAX_LENGTH) {
-      int len = NSTRING_LEN(body);
+      int len = NODE_STRING_LEN(body);
       StrNode* sn = STR_(body);
 
       if (len * qn->lower <= EXPAND_STRING_MAX_LENGTH) {
@@ -4278,17 +4750,17 @@ setup_tree(Node* node, regex_t* reg, int state, ScanEnv* env)
     } while (r == 0 && IS_NOT_NULL(node = NODE_CDR(node)));
     break;
 
-  case NODE_STR:
-    if (IS_IGNORECASE(reg->options) && !NSTRING_IS_RAW(node)) {
+  case NODE_STRING:
+    if (IS_IGNORECASE(reg->options) && !NODE_STRING_IS_RAW(node)) {
       r = expand_case_fold_string(node, reg);
     }
     break;
 
-  case NODE_BREF:
+  case NODE_BACKREF:
     {
       int i;
       int* p;
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
       p = BACKREFS_P(br);
       for (i = 0; i < br->back_num; i++) {
         if (p[i] > env->num_mem)  return ONIGERR_INVALID_BACKREF;
@@ -4311,14 +4783,14 @@ setup_tree(Node* node, regex_t* reg, int state, ScanEnv* env)
       case ENCLOSURE_OPTION:
         {
           OnigOptionType options = reg->options;
-          reg->options = ENCLOSURE_(node)->o.option;
+          reg->options = ENCLOSURE_(node)->o.options;
           r = setup_tree(NODE_BODY(node), reg, state, env);
           reg->options = options;
         }
         break;
 
       case ENCLOSURE_MEMORY:
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
         state |= en->m.called_state;
 #endif
 
@@ -4343,6 +4815,17 @@ setup_tree(Node* node, regex_t* reg, int state, ScanEnv* env)
           }
         }
         break;
+
+      case ENCLOSURE_IF_ELSE:
+        r = setup_tree(NODE_BODY(node), reg, (state | IN_ALT), env);
+        if (r != 0) return r;
+        if (IS_NOT_NULL(en->te.Then)) {
+          r = setup_tree(en->te.Then, reg, (state | IN_ALT), env);
+          if (r != 0) return r;
+        }
+        if (IS_NOT_NULL(en->te.Else))
+          r = setup_tree(en->te.Else, reg, (state | IN_ALT), env);
+        break;
       }
     }
     break;
@@ -4355,11 +4838,12 @@ setup_tree(Node* node, regex_t* reg, int state, ScanEnv* env)
     r = setup_anchor(node, reg, state, env);
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
 #endif
   case NODE_CTYPE:
   case NODE_CCLASS:
+  case NODE_GIMMICK:
   default:
     break;
   }
@@ -4487,7 +4971,7 @@ distance_value(MinMaxLen* mm)
 
   OnigLen d;
 
-  if (mm->max == ONIG_INFINITE_DISTANCE) return 0;
+  if (mm->max == INFINITE_LEN) return 0;
 
   d = mm->max - mm->min;
   if (d < (OnigLen )(sizeof(dist_vals)/sizeof(dist_vals[0])))
@@ -5048,15 +5532,15 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
     }
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     {
       StrNode* sn = STR_(node);
       int slen = sn->end - sn->s;
-      int is_raw = NSTRING_IS_RAW(node);
+      int is_raw = NODE_STRING_IS_RAW(node);
 
-      if (! NSTRING_IS_AMBIG(node)) {
+      if (! NODE_STRING_IS_AMBIG(node)) {
         concat_opt_exact_info_str(&opt->exb, sn->s, sn->end,
-                                  NSTRING_IS_RAW(node), env->enc);
+                                  NODE_STRING_IS_RAW(node), env->enc);
         if (slen > 0) {
           add_char_opt_map_info(&opt->map, *(sn->s), env->enc);
         }
@@ -5065,7 +5549,7 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
       else {
         int max;
 
-        if (NSTRING_IS_DONT_GET_OPT_INFO(node)) {
+        if (NODE_STRING_IS_DONT_GET_OPT_INFO(node)) {
           int n = onigenc_strlen(env->enc, sn->s, sn->end);
           max = ONIGENC_MBC_MAXLEN_DIST(env->enc) * n;
         }
@@ -5191,24 +5675,24 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
     }
     break;
 
-  case NODE_BREF:
-    {
+  case NODE_BACKREF:
+    if (! NODE_IS_CHECKER(node)) {
       int i;
       int* backs;
       OnigLen min, max, tmin, tmax;
       MemEnv* mem_env = SCANENV_MEMENV(env->scan_env);
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
 
       if (NODE_IS_RECURSION(node)) {
-        set_mml(&opt->len, 0, ONIG_INFINITE_DISTANCE);
+        set_mml(&opt->len, 0, INFINITE_LEN);
         break;
       }
       backs = BACKREFS_P(br);
-      min = get_min_len(mem_env[backs[0]].node, env->scan_env);
-      max = get_max_len(mem_env[backs[0]].node, env->scan_env);
+      min = tree_min_len(mem_env[backs[0]].node, env->scan_env);
+      max = tree_max_len(mem_env[backs[0]].node, env->scan_env);
       for (i = 1; i < br->back_num; i++) {
-        tmin = get_min_len(mem_env[backs[i]].node, env->scan_env);
-        tmax = get_max_len(mem_env[backs[i]].node, env->scan_env);
+        tmin = tree_min_len(mem_env[backs[i]].node, env->scan_env);
+        tmax = tree_max_len(mem_env[backs[i]].node, env->scan_env);
         if (min > tmin) min = tmin;
         if (max < tmax) max = tmax;
       }
@@ -5216,13 +5700,13 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     if (NODE_IS_RECURSION(node))
-      set_mml(&opt->len, 0, ONIG_INFINITE_DISTANCE);
+      set_mml(&opt->len, 0, INFINITE_LEN);
     else {
       OnigOptionType save = env->options;
-      env->options = ENCLOSURE_(NODE_BODY(node))->o.option;
+      env->options = ENCLOSURE_(NODE_BODY(node))->o.options;
       r = optimize_node_left(NODE_BODY(node), opt, env);
       env->options = save;
     }
@@ -5242,7 +5726,7 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
       if (qn->lower == 0 && IS_REPEAT_INFINITE(qn->upper)) {
         if (env->mmd.max == 0 &&
             NODE_IS_ANYCHAR(NODE_BODY(node)) && qn->greedy != 0) {
-          if (IS_MULTILINE(env->options))
+          if (IS_MULTILINE(CTYPE_OPTION(NODE_QUANT_BODY(qn), env)))
             add_opt_anc_info(&opt->anc, ANCHOR_ANYCHAR_STAR_ML);
           else
             add_opt_anc_info(&opt->anc, ANCHOR_ANYCHAR_STAR);
@@ -5274,7 +5758,7 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
 
       min = distance_multiply(nopt.len.min, qn->lower);
       if (IS_REPEAT_INFINITE(qn->upper))
-        max = (nopt.len.max > 0 ? ONIG_INFINITE_DISTANCE : 0);
+        max = (nopt.len.max > 0 ? INFINITE_LEN : 0);
       else
         max = distance_multiply(nopt.len.max, qn->upper);
 
@@ -5291,20 +5775,20 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
         {
           OnigOptionType save = env->options;
 
-          env->options = en->o.option;
+          env->options = en->o.options;
           r = optimize_node_left(NODE_BODY(node), opt, env);
           env->options = save;
         }
         break;
 
       case ENCLOSURE_MEMORY:
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
         en->opt_count++;
         if (en->opt_count > MAX_NODE_OPT_INFO_REF_COUNT) {
           OnigLen min, max;
 
           min = 0;
-          max = ONIG_INFINITE_DISTANCE;
+          max = INFINITE_LEN;
           if (NODE_IS_MIN_FIXED(node)) min = en->min_len;
           if (NODE_IS_MAX_FIXED(node)) max = en->max_len;
           set_mml(&opt->len, min, max);
@@ -5324,10 +5808,39 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
       case ENCLOSURE_STOP_BACKTRACK:
         r = optimize_node_left(NODE_BODY(node), opt, env);
         break;
+
+      case ENCLOSURE_IF_ELSE:
+        {
+          OptEnv nenv;
+          NodeOptInfo nopt;
+
+          copy_opt_env(&nenv, env);
+          r = optimize_node_left(NODE_ENCLOSURE_BODY(en), &nopt, &nenv);
+          if (r == 0) {
+            add_mml(&nenv.mmd, &nopt.len);
+            concat_left_node_opt_info(env->enc, opt, &nopt);
+            if (IS_NOT_NULL(en->te.Then)) {
+              r = optimize_node_left(en->te.Then, &nopt, &nenv);
+              if (r == 0) {
+                concat_left_node_opt_info(env->enc, opt, &nopt);
+              }
+            }
+
+            if (IS_NOT_NULL(en->te.Else)) {
+              r = optimize_node_left(en->te.Else, &nopt, env);
+              if (r == 0)
+                alt_merge_node_opt_info(opt, &nopt, env);
+            }
+          }
+        }
+        break;
       }
     }
     break;
 
+  case NODE_GIMMICK:
+    break;
+
   default:
 #ifdef ONIG_DEBUG
     fprintf(stderr, "optimize_node_left: undefined node type %d\n", NODE_TYPE(node));
@@ -5379,7 +5892,7 @@ set_optimize_exact_info(regex_t* reg, OptExactInfo* e)
   reg->dmin = e->mmd.min;
   reg->dmax = e->mmd.max;
 
-  if (reg->dmin != ONIG_INFINITE_DISTANCE) {
+  if (reg->dmin != INFINITE_LEN) {
     reg->threshold_len = reg->dmin + (reg->exact_end - reg->exact);
   }
 
@@ -5398,7 +5911,7 @@ set_optimize_map_info(regex_t* reg, OptMapInfo* m)
   reg->dmin       = m->mmd.min;
   reg->dmax       = m->mmd.max;
 
-  if (reg->dmin != ONIG_INFINITE_DISTANCE) {
+  if (reg->dmin != INFINITE_LEN) {
     reg->threshold_len = reg->dmin + 1;
   }
 }
@@ -5531,14 +6044,14 @@ static void print_enc_string(FILE* fp, OnigEncoding enc,
 static void
 print_distance_range(FILE* f, OnigLen a, OnigLen b)
 {
-  if (a == ONIG_INFINITE_DISTANCE)
+  if (a == INFINITE_LEN)
     fputs("inf", f);
   else
     fprintf(f, "(%u)", a);
 
   fputs("-", f);
 
-  if (b == ONIG_INFINITE_DISTANCE)
+  if (b == INFINITE_LEN)
     fputs("inf", f);
   else
     fprintf(f, "(%u)", b);
@@ -5656,7 +6169,7 @@ onig_free_body(regex_t* reg)
     if (IS_NOT_NULL(reg->int_map))          xfree(reg->int_map);
     if (IS_NOT_NULL(reg->int_map_backward)) xfree(reg->int_map_backward);
     if (IS_NOT_NULL(reg->repeat_range))     xfree(reg->repeat_range);
-    if (IS_NOT_NULL(reg->chain))            onig_free(reg->chain);
+    if (IS_NOT_NULL(REG_EXTP(reg)))         xfree(REG_EXTP(reg));
 
 #ifdef USE_NAMED_GROUP
     onig_names_free(reg);
@@ -5702,7 +6215,7 @@ onig_compile(regex_t* reg, const UChar* pattern, const UChar* pattern_end,
   int r, init_size;
   Node*  root;
   ScanEnv  scan_env;
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   UnsetAddrList  uslist;
 #endif
 
@@ -5751,7 +6264,7 @@ onig_compile(regex_t* reg, const UChar* pattern, const UChar* pattern_end,
   r = check_backrefs(root, &scan_env);
   if (r != 0) goto err;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   if (scan_env.num_call > 0) {
     r = unset_addr_list_init(&uslist, scan_env.num_call);
     if (r != 0) goto err;
@@ -5791,12 +6304,12 @@ onig_compile(regex_t* reg, const UChar* pattern, const UChar* pattern_end,
 
 #ifdef USE_COMBINATION_EXPLOSION_CHECK
   if (scan_env.backrefed_mem == 0
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
       || scan_env.num_call == 0
 #endif
       ) {
     setup_comb_exp_check(root, 0, &scan_env);
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     if (scan_env.has_recursion != 0) {
       scan_env.num_comb_exp_check = 0;
     }
@@ -5829,8 +6342,17 @@ onig_compile(regex_t* reg, const UChar* pattern, const UChar* pattern_end,
 
   r = compile_tree(root, reg, &scan_env);
   if (r == 0) {
+    if (scan_env.keep_num > 0) {
+      r = add_opcode(reg, OP_UPDATE_VAR);
+      if (r != 0) goto err;
+      r = add_update_var_type(reg, UPDATE_VAR_KEEP_FROM_STACK_LAST);
+      if (r != 0) goto err;
+      r = add_mem_num(reg, 0 /* not used */);
+      if (r != 0) goto err;
+    }
+
     r = add_opcode(reg, OP_END);
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     if (scan_env.num_call > 0) {
       r = unset_addr_list_fix(&uslist, reg);
       unset_addr_list_end(&uslist);
@@ -5847,7 +6369,7 @@ onig_compile(regex_t* reg, const UChar* pattern, const UChar* pattern_end,
         reg->stack_pop_level = STACK_POP_LEVEL_FREE;
     }
   }
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   else if (scan_env.num_call > 0) {
     unset_addr_list_end(&uslist);
   }
@@ -5865,7 +6387,7 @@ onig_compile(regex_t* reg, const UChar* pattern, const UChar* pattern_end,
   return r;
 
  err_unset:
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   if (scan_env.num_call > 0) {
     unset_addr_list_end(&uslist);
   }
@@ -5890,8 +6412,8 @@ static int onig_inited = 0;
 
 extern int
 onig_reg_init(regex_t* reg, OnigOptionType option,
-	      OnigCaseFoldType case_fold_flag,
-	      OnigEncoding enc, OnigSyntaxType* syntax)
+              OnigCaseFoldType case_fold_flag,
+              OnigEncoding enc, OnigSyntaxType* syntax)
 {
   int r;
 
@@ -5938,7 +6460,7 @@ onig_reg_init(regex_t* reg, OnigOptionType option,
   (reg)->exact            = (UChar* )NULL;
   (reg)->int_map          = (int* )NULL;
   (reg)->int_map_backward = (int* )NULL;
-  (reg)->chain            = (regex_t* )NULL;
+  REG_EXTPL(reg) = NULL;
 
   (reg)->p                = (UChar* )NULL;
   (reg)->alloc            = 0;
@@ -6165,11 +6687,13 @@ OnigOpInfoType OnigOpInfo[] = {
   { OP_BEGIN_POSITION,      "begin-position",  ARG_NON },
   { OP_BACKREF1,            "backref1",             ARG_NON },
   { OP_BACKREF2,            "backref2",             ARG_NON },
-  { OP_BACKREFN,            "backrefn",             ARG_MEMNUM  },
-  { OP_BACKREFN_IC,         "backrefn-ic",          ARG_SPECIAL },
+  { OP_BACKREF_N,            "backref-n",           ARG_MEMNUM  },
+  { OP_BACKREF_N_IC,         "backref-n-ic",        ARG_SPECIAL },
   { OP_BACKREF_MULTI,       "backref_multi",        ARG_SPECIAL },
   { OP_BACKREF_MULTI_IC,    "backref_multi-ic",     ARG_SPECIAL },
-  { OP_BACKREF_WITH_LEVEL,    "backref_at_level",     ARG_SPECIAL },
+  { OP_BACKREF_WITH_LEVEL,  "backref_with_level",   ARG_SPECIAL },
+  { OP_BACKREF_CHECK,       "backref_check",        ARG_SPECIAL },
+  { OP_BACKREF_CHECK_WITH_LEVEL, "backref_check_with_level", ARG_SPECIAL },
   { OP_MEMORY_START_PUSH,   "mem-start-push",       ARG_MEMNUM  },
   { OP_MEMORY_START,        "mem-start",            ARG_MEMNUM  },
   { OP_MEMORY_END_PUSH,     "mem-end-push",         ARG_MEMNUM  },
@@ -6181,6 +6705,7 @@ OnigOpInfoType OnigOpInfo[] = {
   { OP_FAIL,                "fail",                 ARG_NON },
   { OP_JUMP,                "jump",                 ARG_RELADDR },
   { OP_PUSH,                "push",                 ARG_RELADDR },
+  { OP_PUSH_SUPER,          "push_SUPER",           ARG_RELADDR },
   { OP_POP,                 "pop",                  ARG_NON },
   { OP_PUSH_OR_JUMP_EXACT1, "push-or-jump-e1",      ARG_SPECIAL },
   { OP_PUSH_IF_PEEK_NEXT,   "push-if-peek-next",    ARG_SPECIAL },
@@ -6194,10 +6719,10 @@ OnigOpInfoType OnigOpInfo[] = {
   { OP_EMPTY_CHECK_END,     "empty-check-end",      ARG_MEMNUM  },
   { OP_EMPTY_CHECK_END_MEMST,"empty-check-end-memst", ARG_MEMNUM  },
   { OP_EMPTY_CHECK_END_MEMST_PUSH,"empty-check-end-memst-push", ARG_MEMNUM  },
-  { OP_PUSH_POS,             "push-pos",             ARG_NON },
-  { OP_POP_POS,              "pop-pos",              ARG_NON },
-  { OP_PUSH_POS_NOT,         "push-pos-not",         ARG_RELADDR },
-  { OP_FAIL_POS,             "fail-pos",             ARG_NON },
+  { OP_PREC_READ_START,      "push-pos",             ARG_NON },
+  { OP_PREC_READ_END,        "pop-pos",              ARG_NON },
+  { OP_PUSH_PREC_READ_NOT,   "push-prec-read-not",   ARG_RELADDR },
+  { OP_FAIL_PREC_READ_NOT,   "fail-prec-read-not",   ARG_NON },
   { OP_PUSH_STOP_BT,         "push-stop-bt",         ARG_NON },
   { OP_POP_STOP_BT,          "pop-stop-bt",          ARG_NON },
   { OP_LOOK_BEHIND,          "look-behind",          ARG_SPECIAL },
@@ -6205,6 +6730,8 @@ OnigOpInfoType OnigOpInfo[] = {
   { OP_FAIL_LOOK_BEHIND_NOT, "fail-look-behind-not", ARG_NON },
   { OP_CALL,                 "call",                 ARG_ABSADDR },
   { OP_RETURN,               "return",               ARG_NON },
+  { OP_PUSH_SAVE_VAL,        "push-save-val",        ARG_SPECIAL },
+  { OP_UPDATE_VAR,           "update-var",           ARG_SPECIAL },
   { OP_STATE_CHECK_PUSH,         "state-check-push",         ARG_SPECIAL },
   { OP_STATE_CHECK_PUSH_OR_JUMP, "state-check-push-or-jump", ARG_SPECIAL },
   { OP_STATE_CHECK,              "state-check",              ARG_STATE_CHECK },
@@ -6272,6 +6799,7 @@ onig_print_compiled_byte_code(FILE* f, UChar* bp, UChar** nextp, UChar* start,
   MemNumType mem;
   StateCheckNumType scn;
   OnigCodePoint code;
+  OnigOptionType option;
   UChar *q;
 
   fprintf(f, "%s", op2name(*bp));
@@ -6421,7 +6949,7 @@ onig_print_compiled_byte_code(FILE* f, UChar* bp, UChar** nextp, UChar* start,
       }
       break;
 
-    case OP_BACKREFN_IC:
+    case OP_BACKREF_N_IC:
       mem = *((MemNumType* )bp);
       bp += SIZE_MEMNUM;
       fprintf(f, ":%d", mem);
@@ -6429,6 +6957,7 @@ onig_print_compiled_byte_code(FILE* f, UChar* bp, UChar** nextp, UChar* start,
 
     case OP_BACKREF_MULTI_IC:
     case OP_BACKREF_MULTI:
+    case OP_BACKREF_CHECK:
       fputs(" ", f);
       GET_LENGTH_INC(len, bp);
       for (i = 0; i < len; i++) {
@@ -6439,12 +6968,13 @@ onig_print_compiled_byte_code(FILE* f, UChar* bp, UChar** nextp, UChar* start,
       break;
 
     case OP_BACKREF_WITH_LEVEL:
+      GET_OPTION_INC(option, bp);
+      fprintf(f, ":%d", option);
+      /* fall */
+    case OP_BACKREF_CHECK_WITH_LEVEL:
       {
-        OnigOptionType option;
         LengthType level;
 
-        GET_OPTION_INC(option, bp);
-        fprintf(f, ":%d", option);
         GET_LENGTH_INC(level, bp);
         fprintf(f, ":%d", level);
 
@@ -6501,6 +7031,24 @@ onig_print_compiled_byte_code(FILE* f, UChar* bp, UChar** nextp, UChar* start,
       p_rel_addr(f, addr, bp, start);
       break;
 
+    case OP_PUSH_SAVE_VAL:
+      {
+        SaveType type;
+        GET_SAVE_TYPE_INC(type, bp);
+        GET_MEMNUM_INC(mem, bp);
+        fprintf(f, ":%d:%d", type, mem);
+      }
+      break;
+
+    case OP_UPDATE_VAR:
+      {
+        UpdateVarType type;
+        GET_UPDATE_VAR_TYPE_INC(type, bp);
+        GET_MEMNUM_INC(mem, bp);
+        fprintf(f, ":%d:%d", type, mem);
+      }
+      break;
+
     default:
       fprintf(stderr, "onig_print_compiled_byte_code: undefined code %d\n",
 	      *--bp);
@@ -6576,9 +7124,9 @@ print_indent_tree(FILE* f, Node* node, int indent)
     }
     break;
 
-  case NODE_STR:
+  case NODE_STRING:
     fprintf(f, "<string%s:%p>",
-	    (NSTRING_IS_RAW(node) ? "-raw" : ""), node);
+	    (NODE_STRING_IS_RAW(node) ? "-raw" : ""), node);
     for (p = STR_(node)->s; p < STR_(node)->end; p++) {
       if (*p >= 0x20 && *p < 0x7f)
         fputc(*p, f);
@@ -6659,12 +7207,12 @@ print_indent_tree(FILE* f, Node* node, int indent)
     }
     break;
 
-  case NODE_BREF:
+  case NODE_BACKREF:
     {
       int* p;
-      BRefNode* br = BREF_(node);
+      BackRefNode* br = BACKREF_(node);
       p = BACKREFS_P(br);
-      fprintf(f, "<backref:%p>", node);
+      fprintf(f, "<backref%s:%p>", NODE_IS_CHECKER(node) ? "-checker" : "", node);
       for (i = 0; i < br->back_num; i++) {
         if (i > 0) fputs(", ", f);
         fprintf(f, "%d", p[i]);
@@ -6672,7 +7220,7 @@ print_indent_tree(FILE* f, Node* node, int indent)
     }
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case NODE_CALL:
     {
       CallNode* cn = CALL_(node);
@@ -6693,10 +7241,10 @@ print_indent_tree(FILE* f, Node* node, int indent)
     fprintf(f, "<enclosure:%p> ", node);
     switch (ENCLOSURE_(node)->type) {
     case ENCLOSURE_OPTION:
-      fprintf(f, "option:%d", ENCLOSURE_(node)->option);
+      fprintf(f, "option:%d", ENCLOSURE_(node)->o.options);
       break;
     case ENCLOSURE_MEMORY:
-      fprintf(f, "memory:%d", ENCLOSURE_(node)->regnum);
+      fprintf(f, "memory:%d", ENCLOSURE_(node)->m.regnum);
       break;
     case ENCLOSURE_STOP_BACKTRACK:
       fprintf(f, "stop-bt");
@@ -6709,6 +7257,24 @@ print_indent_tree(FILE* f, Node* node, int indent)
     print_indent_tree(f, NODE_BODY(node), indent + add);
     break;
 
+  case NODE_GIMMICK:
+    fprintf(f, "<gimmick:%p> ", node);
+    switch (GIMMICK_(node)->type) {
+    case GIMMICK_FAIL:
+      fprintf(f, "fail");
+      break;
+    case GIMMICK_KEEP:
+      fprintf(f, "keep:%d", GIMMICK_(node)->id);
+      break;
+    case GIMMICK_SAVE:
+      fprintf(f, "save:%d:%d", GIMMICK_(node)->detail_type, GIMMICK_(node)->id);
+      break;
+    case GIMMICK_UPDATE_VAR:
+      fprintf(f, "update_var:%d:%d", GIMMICK_(node)->detail_type, GIMMICK_(node)->id);
+      break;
+    }
+    break;
+
   default:
     fprintf(f, "print_indent_tree: undefined node type %d\n", NODE_TYPE(node));
     break;
diff --git a/src/regenc.h b/src/regenc.h
index 897c704..abc26be 100644
--- a/src/regenc.h
+++ b/src/regenc.h
@@ -239,5 +239,7 @@ ONIG_EXTERN const unsigned short OnigEncAsciiCtypeTable[];
  (ONIGENC_IS_ASCII_CODE_CTYPE(code, ONIGENC_CTYPE_UPPER) ||\
   ONIGENC_IS_ASCII_CODE_CTYPE(code, ONIGENC_CTYPE_LOWER))
    
+#define ONIGENC_IS_UNICODE_ENCODING(enc) \
+  ((enc)->is_code_ctype == onigenc_unicode_is_code_ctype)
 
 #endif /* REGENC_H */
diff --git a/src/regerror.c b/src/regerror.c
index 0285272..a430e60 100644
--- a/src/regerror.c
+++ b/src/regerror.c
@@ -174,6 +174,12 @@ onig_error_code_to_format(int code)
     p = "group number is too big for capture history"; break;
   case ONIGERR_INVALID_CHAR_PROPERTY_NAME:
     p = "invalid character property name {%n}"; break;
+  case ONIGERR_INVALID_IF_ELSE_SYNTAX:
+    p = "invalid if-else syntax"; break;
+  case ONIGERR_INVALID_ABSENT_GROUP_PATTERN:
+    p = "invalid absent group pattern"; break;
+  case ONIGERR_INVALID_ABSENT_GROUP_GENERATOR_PATTERN:
+    p = "invalid absent group generator pattern"; break;
   case ONIGERR_NOT_SUPPORTED_ENCODING_COMBINATION:
     p = "not supported encoding combination"; break;
   case ONIGERR_INVALID_COMBINATION_OF_OPTIONS:
diff --git a/src/regexec.c b/src/regexec.c
index f66da1f..e7dfb96 100644
--- a/src/regexec.c
+++ b/src/regexec.c
@@ -305,32 +305,85 @@ onig_region_copy(OnigRegion* to, OnigRegion* from)
 /** stack **/
 #define INVALID_STACK_INDEX   -1
 
+#define STK_ALT_FLAG               0x0001
+
 /* stack type */
 /* used by normal-POP */
-#define STK_ALT                    0x0001
-#define STK_LOOK_BEHIND_NOT        0x0002
-#define STK_POS_NOT                0x0003
+#define STK_SUPER_ALT             STK_ALT_FLAG
+#define STK_ALT                   (0x0002 | STK_ALT_FLAG)
+#define STK_ALT_PREC_READ_NOT     (0x0004 | STK_ALT_FLAG)
+#define STK_ALT_LOOK_BEHIND_NOT   (0x0006 | STK_ALT_FLAG)
 /* handled by normal-POP */
 #define STK_MEM_START              0x0100
 #define STK_MEM_END                0x8200
 #define STK_REPEAT_INC             0x0300
 #define STK_STATE_CHECK_MARK       0x1000
 /* avoided by normal-POP */
+#define STK_VOID                   0x0000  /* for fill a blank */
 #define STK_EMPTY_CHECK_START      0x3000
 #define STK_EMPTY_CHECK_END        0x5000  /* for recursive call */
 #define STK_MEM_END_MARK           0x8400
 #define STK_POS                    0x0500  /* used when POP-POS */
-#define STK_STOP_BT                0x0600  /* mark for "(?>...)" */
+#define STK_STOP_BACKTRACK         0x0600  /* mark for "(?>...)" */
 #define STK_REPEAT                 0x0700
 #define STK_CALL_FRAME             0x0800
 #define STK_RETURN                 0x0900
-#define STK_VOID                   0x0a00  /* for fill a blank */
+#define STK_SAVE_VAL               0x0a00
 
 /* stack type check mask */
-#define STK_MASK_POP_USED          0x00ff
-#define STK_MASK_TO_VOID_TARGET    0x10ff
+#define STK_MASK_POP_USED          STK_ALT_FLAG
+#define STK_MASK_TO_VOID_TARGET    0x10fe
 #define STK_MASK_MEM_END_OR_MARK   0x8000  /* MEM_END or MEM_END_MARK */
 
+typedef intptr_t StackIndex;
+
+typedef struct _StackType {
+  unsigned int type;
+  union {
+    struct {
+      UChar *pcode;      /* byte code position */
+      UChar *pstr;       /* string position */
+      UChar *pstr_prev;  /* previous char position of pstr */
+#ifdef USE_COMBINATION_EXPLOSION_CHECK
+      unsigned int state_check;
+#endif
+    } state;
+    struct {
+      int   count;       /* for OP_REPEAT_INC, OP_REPEAT_INC_NG */
+      UChar *pcode;      /* byte code position (head of repeated target) */
+      int   num;         /* repeat id */
+    } repeat;
+    struct {
+      StackIndex si;     /* index of stack */
+    } repeat_inc;
+    struct {
+      int num;           /* memory num */
+      UChar *pstr;       /* start/end position */
+      /* Following information is set, if this stack type is MEM-START */
+      StackIndex start;  /* prev. info (for backtrack  "(...)*" ) */
+      StackIndex end;    /* prev. info (for backtrack  "(...)*" ) */
+    } mem;
+    struct {
+      int num;           /* null check id */
+      UChar *pstr;       /* start position */
+    } empty_check;
+#ifdef USE_CALL
+    struct {
+      UChar *ret_addr;   /* byte code position */
+      int    num;        /* null check id */
+      UChar *pstr;       /* string position */
+    } call_frame;
+#endif
+    struct {
+      int id;
+      enum SaveType type;
+      UChar* v;
+      UChar* v2;
+    } val;
+  } u;
+} StackType;
+
+
 #ifdef USE_FIND_LONGEST_SEARCH_ALL_OF_RANGE
 #define MATCH_ARG_INIT(msa, reg, arg_option, arg_region, arg_start) do {\
   (msa).stack_p  = (void* )0;\
@@ -396,28 +449,28 @@ onig_region_copy(OnigRegion* to, OnigRegion* from)
   if (msa->stack_p) {\
     is_alloca  = 0;\
     alloc_base = msa->stack_p;\
-    stk_base   = (OnigStackType* )(alloc_base\
-                 + (sizeof(OnigStackIndex) * msa->ptr_num));\
+    stk_base   = (StackType* )(alloc_base\
+                 + (sizeof(StackIndex) * msa->ptr_num));\
     stk        = stk_base;\
     stk_end    = stk_base + msa->stack_n;\
   }\
   else if (msa->ptr_num > ALLOCA_PTR_NUM_LIMIT) {\
     is_alloca  = 0;\
-    alloc_base = (char* )xmalloc(sizeof(OnigStackIndex) * msa->ptr_num\
-                  + sizeof(OnigStackType) * (stack_num));\
+    alloc_base = (char* )xmalloc(sizeof(StackIndex) * msa->ptr_num\
+                  + sizeof(StackType) * (stack_num));\
     CHECK_NULL_RETURN_MEMERR(alloc_base);\
-    stk_base   = (OnigStackType* )(alloc_base\
-                 + (sizeof(OnigStackIndex) * msa->ptr_num));\
+    stk_base   = (StackType* )(alloc_base\
+                 + (sizeof(StackIndex) * msa->ptr_num));\
     stk        = stk_base;\
     stk_end    = stk_base + (stack_num);\
   }\
   else {\
     is_alloca  = 1;\
-    alloc_base = (char* )xalloca(sizeof(OnigStackIndex) * msa->ptr_num\
-                 + sizeof(OnigStackType) * (stack_num));\
+    alloc_base = (char* )xalloca(sizeof(StackIndex) * msa->ptr_num\
+                 + sizeof(StackType) * (stack_num));\
     CHECK_NULL_RETURN_MEMERR(alloc_base);\
-    stk_base   = (OnigStackType* )(alloc_base\
-                 + (sizeof(OnigStackIndex) * msa->ptr_num));\
+    stk_base   = (StackType* )(alloc_base\
+                 + (sizeof(StackIndex) * msa->ptr_num));\
     stk        = stk_base;\
     stk_end    = stk_base + (stack_num);\
   }\
@@ -427,8 +480,8 @@ onig_region_copy(OnigRegion* to, OnigRegion* from)
 #define STACK_SAVE do{\
   msa->stack_n = stk_end - stk_base;\
   if (is_alloca != 0) {\
-    size_t size = sizeof(OnigStackIndex) * msa->ptr_num \
-                + sizeof(OnigStackType) * msa->stack_n;\
+    size_t size = sizeof(StackIndex) * msa->ptr_num \
+                + sizeof(StackType) * msa->stack_n;\
     msa->stack_p = xmalloc(size);\
     CHECK_NULL_RETURN_MEMERR(msa->stack_p);\
     xmemcpy(msa->stack_p, alloc_base, size);\
@@ -439,8 +492,8 @@ onig_region_copy(OnigRegion* to, OnigRegion* from)
 } while(0)
 
 #define UPDATE_FOR_STACK_REALLOC do{\
-  repeat_stk    = (OnigStackIndex* )alloc_base;\
-  mem_start_stk = (OnigStackIndex* )(repeat_stk + reg->num_repeat);\
+  repeat_stk    = (StackIndex* )alloc_base;\
+  mem_start_stk = (StackIndex* )(repeat_stk + reg->num_repeat);\
   mem_end_stk   = mem_start_stk + num_mem + 1;\
 } while(0)
 
@@ -461,8 +514,8 @@ onig_set_match_stack_limit_size(unsigned int size)
 
 static int
 stack_double(int is_alloca, char** arg_alloc_base,
-	     OnigStackType** arg_stk_base,
-	     OnigStackType** arg_stk_end, OnigStackType** arg_stk,
+	     StackType** arg_stk_base,
+	     StackType** arg_stk_end, StackType** arg_stk,
 	     OnigMatchArg* msa)
 {
   unsigned int n;
@@ -471,7 +524,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
   size_t new_size;
   char* alloc_base;
   char* new_alloc_base;
-  OnigStackType *stk_base, *stk_end, *stk;
+  StackType *stk_base, *stk_end, *stk;
 
   alloc_base = *arg_alloc_base;
   stk_base = *arg_stk_base;
@@ -479,9 +532,9 @@ stack_double(int is_alloca, char** arg_alloc_base,
   stk      = *arg_stk;
 
   n = stk_end - stk_base;
-  size = sizeof(OnigStackIndex) * msa->ptr_num + sizeof(OnigStackType) * n;
+  size = sizeof(StackIndex) * msa->ptr_num + sizeof(StackType) * n;
   n *= 2;
-  new_size = sizeof(OnigStackIndex) * msa->ptr_num + sizeof(OnigStackType) * n;
+  new_size = sizeof(StackIndex) * msa->ptr_num + sizeof(StackType) * n;
   if (is_alloca != 0) {
     new_alloc_base = (char* )xmalloc(new_size);
     if (IS_NULL(new_alloc_base)) {
@@ -507,8 +560,8 @@ stack_double(int is_alloca, char** arg_alloc_base,
   alloc_base = new_alloc_base;
   used = stk - stk_base;
   *arg_alloc_base = alloc_base;
-  *arg_stk_base   = (OnigStackType* )(alloc_base
-		       + (sizeof(OnigStackIndex) * msa->ptr_num));
+  *arg_stk_base   = (StackType* )(alloc_base
+		       + (sizeof(StackIndex) * msa->ptr_num));
   *arg_stk      = *arg_stk_base + used;
   *arg_stk_end  = *arg_stk_base + n;
   return 0;
@@ -516,8 +569,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
 
 #define STACK_ENSURE(n)	do {\
   if (stk_end - stk < (n)) {\
-    int r = stack_double(is_alloca, &alloc_base, &stk_base, &stk_end, &stk,\
-                         msa);\
+    int r = stack_double(is_alloca, &alloc_base, &stk_base, &stk_end, &stk, msa);\
     if (r != 0) { STACK_SAVE; return r; } \
     is_alloca = 0;\
     UPDATE_FOR_STACK_REALLOC;\
@@ -610,12 +662,14 @@ stack_double(int is_alloca, char** arg_alloc_base,
 } while(0)
 #endif /* USE_COMBINATION_EXPLOSION_CHECK */
 
-#define STACK_PUSH_ALT(pat,s,sprev)     STACK_PUSH(STK_ALT,pat,s,sprev)
+#define STACK_PUSH_ALT(pat,s,sprev)       STACK_PUSH(STK_ALT,pat,s,sprev)
+#define STACK_PUSH_SUPER_ALT(pat,s,sprev) STACK_PUSH(STK_SUPER_ALT,pat,s,sprev)
 #define STACK_PUSH_POS(s,sprev)         STACK_PUSH(STK_POS,NULL_UCHARP,s,sprev)
-#define STACK_PUSH_POS_NOT(pat,s,sprev) STACK_PUSH(STK_POS_NOT,pat,s,sprev)
-#define STACK_PUSH_STOP_BT              STACK_PUSH_TYPE(STK_STOP_BT)
-#define STACK_PUSH_LOOK_BEHIND_NOT(pat,s,sprev) \
-        STACK_PUSH(STK_LOOK_BEHIND_NOT,pat,s,sprev)
+#define STACK_PUSH_ALT_PREC_READ_NOT(pat,s,sprev) \
+  STACK_PUSH(STK_ALT_PREC_READ_NOT,pat,s,sprev)
+#define STACK_PUSH_STOP_BACKTRACK        STACK_PUSH_TYPE(STK_STOP_BACKTRACK)
+#define STACK_PUSH_ALT_LOOK_BEHIND_NOT(pat,s,sprev) \
+  STACK_PUSH(STK_ALT_LOOK_BEHIND_NOT,pat,s,sprev)
 
 #define STACK_PUSH_REPEAT(id, pat) do {\
   STACK_ENSURE(1);\
@@ -725,6 +779,97 @@ stack_double(int is_alloca, char** arg_alloc_base,
   STACK_INC;\
 } while(0)
 
+#define STACK_PUSH_SAVE_VAL(sid, stype, sval) do {\
+  STACK_ENSURE(1);\
+  stk->type = STK_SAVE_VAL;\
+  stk->u.val.id   = (sid);\
+  stk->u.val.type = (stype);\
+  stk->u.val.v    = (UChar* )(sval);\
+  STACK_INC;\
+} while(0)
+
+#define STACK_PUSH_SAVE_VAL_WITH_SPREV(sid, stype, sval) do {\
+  STACK_ENSURE(1);\
+  stk->type = STK_SAVE_VAL;\
+  stk->u.val.id   = (sid);\
+  stk->u.val.type = (stype);\
+  stk->u.val.v    = (UChar* )(sval);\
+  stk->u.val.v2   = sprev;\
+  STACK_INC;\
+} while(0)
+
+#define STACK_GET_SAVE_VAL_TYPE_LAST(stype, sval) do {\
+  StackType *k = stk;\
+  while (k > stk_base) {\
+    k--;\
+    STACK_BASE_CHECK(k, "STACK_GET_SAVE_VAL_TYPE_LAST"); \
+    if (k->type == STK_SAVE_VAL && k->u.val.type == (stype)) {\
+      (sval) = k->u.val.v;\
+      break;\
+    }\
+  }\
+} while (0)
+
+#define STACK_GET_SAVE_VAL_TYPE_LAST_ID(stype, sid, sval) do { \
+  int level = 0;\
+  StackType *k = stk;\
+  while (k > stk_base) {\
+    k--;\
+    STACK_BASE_CHECK(k, "STACK_GET_SAVE_VAL_TYPE_LAST_ID"); \
+    if (k->type == STK_SAVE_VAL && k->u.val.type == (stype)\
+        && k->u.val.id == (sid)) {\
+      if (level == 0) {\
+        (sval) = k->u.val.v;\
+        break;\
+      }\
+    }\
+    else if (k->type == STK_CALL_FRAME)\
+      level--;\
+    else if (k->type == STK_RETURN)\
+      level++;\
+  }\
+} while (0)
+
+#define STACK_GET_SAVE_VAL_TYPE_LAST_ID_WITH_SPREV(stype, sid, sval) do { \
+  int level = 0;\
+  StackType *k = stk;\
+  while (k > stk_base) {\
+    k--;\
+    STACK_BASE_CHECK(k, "STACK_GET_SAVE_VAL_TYPE_LAST_ID"); \
+    if (k->type == STK_SAVE_VAL && k->u.val.type == (stype)\
+        && k->u.val.id == (sid)) {\
+      if (level == 0) {\
+        (sval) = k->u.val.v;\
+        sprev  = k->u.val.v2;\
+        break;\
+      }\
+    }\
+    else if (k->type == STK_CALL_FRAME)\
+      level--;\
+    else if (k->type == STK_RETURN)\
+      level++;\
+  }\
+} while (0)
+
+#define STACK_GET_SAVE_VAL_TYPE_LAST_ID_FROM(stype, sid, sval, stk_from) do { \
+  int level = 0;\
+  StackType *k = (stk_from);\
+  while (k > stk_base) {\
+    STACK_BASE_CHECK(k, "STACK_GET_SAVE_VAL_TYPE_LAST_ID_FROM"); \
+    if (k->type == STK_SAVE_VAL && k->u.val.type == (stype)\
+        && k->u.val.id == (sid)) {\
+      if (level == 0) {\
+        (sval) = k->u.val.v;\
+        break;\
+      }\
+    }\
+    else if (k->type == STK_CALL_FRAME)\
+      level--;\
+    else if (k->type == STK_RETURN)\
+      level++;\
+    k--;\
+  }\
+} while (0)
 
 #ifdef ONIG_DEBUG
 #define STACK_BASE_CHECK(p, at) \
@@ -785,11 +930,11 @@ stack_double(int is_alloca, char** arg_alloc_base,
   }\
 } while(0)
 
-#define STACK_POP_TIL_POS_NOT  do {\
+#define STACK_POP_TIL_ALT_PREC_READ_NOT  do {\
   while (1) {\
     stk--;\
-    STACK_BASE_CHECK(stk, "STACK_POP_TIL_POS_NOT"); \
-    if (stk->type == STK_POS_NOT) break;\
+    STACK_BASE_CHECK(stk, "STACK_POP_TIL_ALT_PREC_READ_NOT"); \
+    if (stk->type == STK_ALT_PREC_READ_NOT) break;\
     else if (stk->type == STK_MEM_START) {\
       mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
       mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
@@ -805,11 +950,11 @@ stack_double(int is_alloca, char** arg_alloc_base,
   }\
 } while(0)
 
-#define STACK_POP_TIL_LOOK_BEHIND_NOT  do {\
+#define STACK_POP_TIL_ALT_LOOK_BEHIND_NOT  do {\
   while (1) {\
     stk--;\
-    STACK_BASE_CHECK(stk, "STACK_POP_TIL_LOOK_BEHIND_NOT"); \
-    if (stk->type == STK_LOOK_BEHIND_NOT) break;\
+    STACK_BASE_CHECK(stk, "STACK_POP_TIL_ALT_LOOK_BEHIND_NOT"); \
+    if (stk->type == STK_ALT_LOOK_BEHIND_NOT) break;\
     else if (stk->type == STK_MEM_START) {\
       mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
       mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
@@ -840,15 +985,15 @@ stack_double(int is_alloca, char** arg_alloc_base,
   }\
 } while(0)
 
-#define STACK_STOP_BT_END do {\
-  OnigStackType *k = stk;\
+#define STACK_STOP_BACKTRACK_END do {\
+  StackType *k = stk;\
   while (1) {\
     k--;\
-    STACK_BASE_CHECK(k, "STACK_STOP_BT_END"); \
+    STACK_BASE_CHECK(k, "STACK_STOP_BACKTRACK_END"); \
     if (IS_TO_VOID_TARGET(k)) {\
       k->type = STK_VOID;\
     }\
-    else if (k->type == STK_STOP_BT) {\
+    else if (k->type == STK_STOP_BACKTRACK) {\
       k->type = STK_VOID;\
       break;\
     }\
@@ -856,7 +1001,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
 } while(0)
 
 #define STACK_EMPTY_CHECK(isnull,id,s) do {\
-  OnigStackType* k = stk;\
+  StackType* k = stk;\
   while (1) {\
     k--;\
     STACK_BASE_CHECK(k, "STACK_EMPTY_CHECK"); \
@@ -871,7 +1016,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
 
 #ifdef USE_INSISTENT_CHECK_CAPTURES_STATUS_IN_ENDLESS_REPEAT
 #define STACK_EMPTY_CHECK_MEMST(isnull,id,s,reg) do {\
-  OnigStackType* k = stk;\
+  StackType* k = stk;\
   while (1) {\
     k--;\
     STACK_BASE_CHECK(k, "STACK_EMPTY_CHECK_MEMST"); \
@@ -912,7 +1057,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
 
 #define STACK_EMPTY_CHECK_MEMST_REC(isnull,id,s,reg) do {\
   int level = 0;\
-  OnigStackType* k = stk;\
+  StackType* k = stk;\
   while (1) {\
     k--;\
     STACK_BASE_CHECK(k, "STACK_EMPTY_CHECK_MEMST_REC"); \
@@ -960,7 +1105,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
 #else
 #define STACK_EMPTY_CHECK_REC(isnull,id,s) do {\
   int level = 0;\
-  OnigStackType* k = stk;\
+  StackType* k = stk;\
   while (1) {\
     k--;\
     STACK_BASE_CHECK(k, "STACK_EMPTY_CHECK_REC"); \
@@ -1000,7 +1145,7 @@ stack_double(int is_alloca, char** arg_alloc_base,
 
 #define STACK_RETURN(addr)  do {\
   int level = 0;\
-  OnigStackType* k = stk;\
+  StackType* k = stk;\
   while (1) {\
     k--;\
     STACK_BASE_CHECK(k, "STACK_RETURN"); \
@@ -1074,27 +1219,26 @@ static int string_cmp_ic(OnigEncoding enc, int case_fold_flag,
 
 
 #define IS_EMPTY_STR           (str == end)
-#define ON_STR_BEGIN(s)       ((s) == str)
-#define ON_STR_END(s)         ((s) == end)
-#ifdef USE_MATCH_RANGE_MUST_BE_INSIDE_OF_SPECIFIED_RANGE
+#define ON_STR_BEGIN(s)        ((s) == str)
+#define ON_STR_END(s)          ((s) == end)
 #define DATA_ENSURE_CHECK1     (s < right_range)
 #define DATA_ENSURE_CHECK(n)   (s + (n) <= right_range)
 #define DATA_ENSURE(n)         if (s + (n) > right_range) goto fail
-#else
-#define DATA_ENSURE_CHECK1     (s < end)
-#define DATA_ENSURE_CHECK(n)   (s + (n) <= end)
-#define DATA_ENSURE(n)         if (s + (n) > end) goto fail
-#endif /* USE_MATCH_RANGE_MUST_BE_INSIDE_OF_SPECIFIED_RANGE */
 
+#ifdef USE_MATCH_RANGE_MUST_BE_INSIDE_OF_SPECIFIED_RANGE
+#define INIT_RIGHT_RANGE    right_range = (UChar* )in_right_range
+#else
+#define INIT_RIGHT_RANGE    right_range = (UChar* )end
+#endif
 
 #ifdef USE_CAPTURE_HISTORY
 static int
-make_capture_history_tree(OnigCaptureTreeNode* node, OnigStackType** kp,
-                          OnigStackType* stk_top, UChar* str, regex_t* reg)
+make_capture_history_tree(OnigCaptureTreeNode* node, StackType** kp,
+                          StackType* stk_top, UChar* str, regex_t* reg)
 {
   int n, r;
   OnigCaptureTreeNode* child;
-  OnigStackType* k = *kp;
+  StackType* k = *kp;
 
   while (k < stk_top) {
     if (k->type == STK_MEM_START) {
@@ -1143,13 +1287,13 @@ static int mem_is_in_memp(int mem, int num, UChar* memp)
 }
 
 static int backref_match_at_nested_level(regex_t* reg
-	 , OnigStackType* top, OnigStackType* stk_base
+	 , StackType* top, StackType* stk_base
 	 , int ignore_case, int case_fold_flag
 	 , int nest, int mem_num, UChar* memp, UChar** s, const UChar* send)
 {
   UChar *ss, *p, *pstart, *pend = NULL_UCHARP;
   int level;
-  OnigStackType* k;
+  StackType* k;
 
   level = 0;
   k = top;
@@ -1197,6 +1341,37 @@ static int backref_match_at_nested_level(regex_t* reg
 
   return 0;
 }
+
+static int
+backref_check_at_nested_level(regex_t* reg,
+                              StackType* top, StackType* stk_base,
+                              int nest, int mem_num, UChar* memp)
+{
+  int level;
+  StackType* k;
+
+  level = 0;
+  k = top;
+  k--;
+  while (k >= stk_base) {
+    if (k->type == STK_CALL_FRAME) {
+      level--;
+    }
+    else if (k->type == STK_RETURN) {
+      level++;
+    }
+    else if (level == nest) {
+      if (k->type == STK_MEM_END) {
+        if (mem_is_in_memp(k->u.mem.num, mem_num, memp)) {
+          return 1;
+        }
+      }
+    }
+    k--;
+  }
+
+  return 0;
+}
 #endif /* USE_BACKREF_WITH_LEVEL */
 
 
@@ -1300,7 +1475,7 @@ typedef struct {
 static int
 match_at(regex_t* reg, const UChar* str, const UChar* end,
 #ifdef USE_MATCH_RANGE_MUST_BE_INSIDE_OF_SPECIFIED_RANGE
-	 const UChar* right_range,
+	 const UChar* in_right_range,
 #endif
 	 const UChar* sstart, UChar* sprev, OnigMatchArg* msa)
 {
@@ -1311,13 +1486,15 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
   MemNumType mem;
   RelAddrType addr;
   UChar *s, *q, *sbegin;
+  UChar *right_range;
   int is_alloca;
   char *alloc_base;
-  OnigStackType *stk_base, *stk, *stk_end;
-  OnigStackType *stkp; /* used as any purpose. */
-  OnigStackIndex si;
-  OnigStackIndex *repeat_stk;
-  OnigStackIndex *mem_start_stk, *mem_end_stk;
+  StackType *stk_base, *stk, *stk_end;
+  StackType *stkp; /* used as any purpose. */
+  StackIndex si;
+  StackIndex *repeat_stk;
+  StackIndex *mem_start_stk, *mem_end_stk;
+  UChar* keep;
 #ifdef USE_COMBINATION_EXPLOSION_CHECK
   int scv;
   unsigned char* state_check_buff = msa->state_check_buff;
@@ -1346,7 +1523,9 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
   STACK_PUSH_ENSURED(STK_ALT, FinishCode);  /* bottom stack */
   best_len = ONIG_MISMATCH;
-  s = (UChar* )sstart;
+  keep = s = (UChar* )sstart;
+  INIT_RIGHT_RANGE;
+
   while (1) {
 #ifdef ONIG_DEBUG_MATCH
     {
@@ -1394,12 +1573,14 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
         best_len = n;
         region = msa->region;
         if (region) {
+          if (keep > s) keep = s;
+
 #ifdef USE_POSIX_API_REGION_OPTION
           if (IS_POSIX_REGION(msa->options)) {
             posix_regmatch_t* rmt = (posix_regmatch_t* )region;
 
-            rmt[0].rm_so = sstart - str;
-            rmt[0].rm_eo = s      - str;
+            rmt[0].rm_so = keep - str;
+            rmt[0].rm_eo = s    - str;
             for (i = 1; i <= num_mem; i++) {
               if (mem_end_stk[i] != INVALID_STACK_INDEX) {
                 if (MEM_STATUS_AT(reg->bt_mem_start, i))
@@ -1418,8 +1599,8 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
           }
           else {
 #endif /* USE_POSIX_API_REGION_OPTION */
-            region->beg[0] = sstart - str;
-            region->end[0] = s      - str;
+            region->beg[0] = keep - str;
+            region->end[0] = s    - str;
             for (i = 1; i <= num_mem; i++) {
               if (mem_end_stk[i] != INVALID_STACK_INDEX) {
                 if (MEM_STATUS_AT(reg->bt_mem_start, i))
@@ -1451,8 +1632,8 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
               }
 
               node->group = 0;
-              node->beg   = sstart - str;
-              node->end   = s      - str;
+              node->beg   = keep - str;
+              node->end   = s    - str;
 
               stkp = stk_base;
               r = make_capture_history_tree(region->history_root, &stkp,
@@ -2138,7 +2319,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
     case OP_MEMORY_START:  MOP_IN(OP_MEMORY_START);
       GET_MEMNUM_INC(mem, p);
-      mem_start_stk[mem] = (OnigStackIndex )((void* )s);
+      mem_start_stk[mem] = (StackIndex )((void* )s);
       MOP_OUT;
       continue;
       break;
@@ -2152,12 +2333,12 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
     case OP_MEMORY_END:  MOP_IN(OP_MEMORY_END);
       GET_MEMNUM_INC(mem, p);
-      mem_end_stk[mem] = (OnigStackIndex )((void* )s);
+      mem_end_stk[mem] = (StackIndex )((void* )s);
       MOP_OUT;
       continue;
       break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     case OP_MEMORY_END_PUSH_REC:  MOP_IN(OP_MEMORY_END_PUSH_REC);
       GET_MEMNUM_INC(mem, p);
       STACK_GET_MEM_START(mem, stkp); /* should be before push mem-end. */
@@ -2169,13 +2350,13 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
     case OP_MEMORY_END_REC:  MOP_IN(OP_MEMORY_END_REC);
       GET_MEMNUM_INC(mem, p);
-      mem_end_stk[mem] = (OnigStackIndex )((void* )s);
+      mem_end_stk[mem] = (StackIndex )((void* )s);
       STACK_GET_MEM_START(mem, stkp);
 
       if (MEM_STATUS_AT(reg->bt_mem_start, mem))
         mem_start_stk[mem] = GET_STACK_INDEX(stkp);
       else
-        mem_start_stk[mem] = (OnigStackIndex )((void* )stkp->u.mem.pstr);
+        mem_start_stk[mem] = (StackIndex )((void* )stkp->u.mem.pstr);
 
       STACK_PUSH_MEM_END_MARK(mem);
       MOP_OUT;
@@ -2193,16 +2374,13 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       goto backref;
       break;
 
-    case OP_BACKREFN:  MOP_IN(OP_BACKREFN);
+    case OP_BACKREF_N:  MOP_IN(OP_BACKREF_N);
       GET_MEMNUM_INC(mem, p);
     backref:
       {
         int len;
         UChar *pstart, *pend;
 
-        /* if you want to remove following line, 
-           you should check in parse and compile time. */
-        if (mem > num_mem) goto fail;
         if (mem_end_stk[mem]   == INVALID_STACK_INDEX) goto fail;
         if (mem_start_stk[mem] == INVALID_STACK_INDEX) goto fail;
 
@@ -2226,15 +2404,12 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       }
       break;
 
-    case OP_BACKREFN_IC:  MOP_IN(OP_BACKREFN_IC);
+    case OP_BACKREF_N_IC:  MOP_IN(OP_BACKREF_N_IC);
       GET_MEMNUM_INC(mem, p);
       {
         int len;
         UChar *pstart, *pend;
 
-        /* if you want to remove following line, 
-           you should check in parse and compile time. */
-        if (mem > num_mem) goto fail;
         if (mem_end_stk[mem]   == INVALID_STACK_INDEX) goto fail;
         if (mem_start_stk[mem] == INVALID_STACK_INDEX) goto fail;
 
@@ -2364,6 +2539,45 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       break;
 #endif
 
+    case OP_BACKREF_CHECK:  MOP_IN(OP_BACKREF_CHECK);
+      {
+        GET_LENGTH_INC(tlen, p);
+        for (i = 0; i < tlen; i++) {
+          GET_MEMNUM_INC(mem, p);
+
+          if (mem_end_stk[mem]   == INVALID_STACK_INDEX) continue;
+          if (mem_start_stk[mem] == INVALID_STACK_INDEX) continue;
+
+          p += (SIZE_MEMNUM * (tlen - i - 1));
+          break; /* success */
+        }
+        if (i == tlen) goto fail;
+        MOP_OUT;
+        continue;
+      }
+      break;
+
+#ifdef USE_BACKREF_WITH_LEVEL
+    case OP_BACKREF_CHECK_WITH_LEVEL:
+      {
+        LengthType level;
+
+        GET_LENGTH_INC(level, p);
+        GET_LENGTH_INC(tlen,  p);
+
+        if (backref_check_at_nested_level(reg, stk, stk_base,
+                                          (int )level, (int )tlen, p) != 0) {
+          p += (SIZE_MEMNUM * tlen);
+        }
+        else
+          goto fail;
+
+        MOP_OUT;
+        continue;
+      }
+      break;
+#endif
+
 #if 0   /* no need: IS_DYNAMIC_OPTION() == 0 */
     case OP_SET_OPTION_PUSH:  MOP_IN(OP_SET_OPTION_PUSH);
       GET_OPTION_INC(option, p);
@@ -2440,7 +2654,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       break;
 #endif
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     case OP_EMPTY_CHECK_END_MEMST_PUSH:
       MOP_IN(OP_EMPTY_CHECK_END_MEMST_PUSH);
       {
@@ -2484,6 +2698,13 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       continue;
       break;
 
+    case OP_PUSH_SUPER:  MOP_IN(OP_PUSH_SUPER);
+      GET_RELADDR_INC(addr, p);
+      STACK_PUSH_SUPER_ALT(p + addr, s, sprev);
+      MOP_OUT;
+      continue;
+      break;
+
 #ifdef USE_COMBINATION_EXPLOSION_CHECK
     case OP_STATE_CHECK_PUSH:  MOP_IN(OP_STATE_CHECK_PUSH);
       GET_STATE_CHECK_NUM_INC(mem, p);
@@ -2652,13 +2873,13 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       goto repeat_inc_ng;
       break;
 
-    case OP_PUSH_POS:  MOP_IN(OP_PUSH_POS);
+    case OP_PREC_READ_START:  MOP_IN(OP_PREC_READ_START);
       STACK_PUSH_POS(s, sprev);
       MOP_OUT;
       continue;
       break;
 
-    case OP_POP_POS:  MOP_IN(OP_POP_POS);
+    case OP_PREC_READ_END:  MOP_IN(OP_PREC_READ_END);
       {
         STACK_POS_END(stkp);
         s     = stkp->u.state.pstr;
@@ -2668,26 +2889,26 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       continue;
       break;
 
-    case OP_PUSH_POS_NOT:  MOP_IN(OP_PUSH_POS_NOT);
+    case OP_PUSH_PREC_READ_NOT:  MOP_IN(OP_PUSH_PREC_READ_NOT);
       GET_RELADDR_INC(addr, p);
-      STACK_PUSH_POS_NOT(p + addr, s, sprev);
+      STACK_PUSH_ALT_PREC_READ_NOT(p + addr, s, sprev);
       MOP_OUT;
       continue;
       break;
 
-    case OP_FAIL_POS:  MOP_IN(OP_FAIL_POS);
-      STACK_POP_TIL_POS_NOT;
+    case OP_FAIL_PREC_READ_NOT:  MOP_IN(OP_FAIL_PREC_READ_NOT);
+      STACK_POP_TIL_ALT_PREC_READ_NOT;
       goto fail;
       break;
 
     case OP_PUSH_STOP_BT:  MOP_IN(OP_PUSH_STOP_BT);
-      STACK_PUSH_STOP_BT;
+      STACK_PUSH_STOP_BACKTRACK;
       MOP_OUT;
       continue;
       break;
 
     case OP_POP_STOP_BT:  MOP_IN(OP_POP_STOP_BT);
-      STACK_STOP_BT_END;
+      STACK_STOP_BACKTRACK_END;
       MOP_OUT;
       continue;
       break;
@@ -2712,7 +2933,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
         /* goto fail; */
       }
       else {
-        STACK_PUSH_LOOK_BEHIND_NOT(p + addr, s, sprev);
+        STACK_PUSH_ALT_LOOK_BEHIND_NOT(p + addr, s, sprev);
         s = q;
         sprev = (UChar* )onigenc_get_prev_char_head(encode, str, s);
       }
@@ -2721,11 +2942,11 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       break;
 
     case OP_FAIL_LOOK_BEHIND_NOT:  MOP_IN(OP_FAIL_LOOK_BEHIND_NOT);
-      STACK_POP_TIL_LOOK_BEHIND_NOT;
+      STACK_POP_TIL_ALT_LOOK_BEHIND_NOT;
       goto fail;
       break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     case OP_CALL:  MOP_IN(OP_CALL);
       GET_ABSADDR_INC(addr, p);
       STACK_PUSH_CALL_FRAME(p);
@@ -2742,6 +2963,56 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       break;
 #endif
 
+    case OP_PUSH_SAVE_VAL: MOP_IN(OP_PUSH_SAVE_VAL);
+      {
+        SaveType type;
+        GET_SAVE_TYPE_INC(type, p);
+        GET_MEMNUM_INC(mem, p); /* mem: save id */
+        switch ((enum SaveType )type) {
+        case SAVE_KEEP:
+          STACK_PUSH_SAVE_VAL(mem, type, s);
+          break;
+
+        case SAVE_S:
+          STACK_PUSH_SAVE_VAL_WITH_SPREV(mem, type, s);
+          break;
+
+        case SAVE_RIGHT_RANGE:
+          STACK_PUSH_SAVE_VAL(mem, SAVE_RIGHT_RANGE, right_range);
+          break;
+        }
+      }
+      MOP_OUT;
+      continue;
+      break;
+
+    case OP_UPDATE_VAR: MOP_IN(OP_UPDATE_VAR);
+      {
+        UpdateVarType type;
+        GET_UPDATE_VAR_TYPE_INC(type, p);
+        GET_MEMNUM_INC(mem, p); /* mem: save id */
+        switch ((enum UpdateVarType )type) {
+        case UPDATE_VAR_KEEP_FROM_STACK_LAST:
+          STACK_GET_SAVE_VAL_TYPE_LAST(SAVE_KEEP, keep);
+          break;
+        case UPDATE_VAR_S_FROM_STACK:
+          STACK_GET_SAVE_VAL_TYPE_LAST_ID_WITH_SPREV(SAVE_S, mem, s);
+          break;
+        case UPDATE_VAR_RIGHT_RANGE_FROM_S_STACK:
+          STACK_GET_SAVE_VAL_TYPE_LAST_ID(SAVE_S, mem, right_range);
+          break;
+        case UPDATE_VAR_RIGHT_RANGE_FROM_STACK:
+          STACK_GET_SAVE_VAL_TYPE_LAST_ID(SAVE_RIGHT_RANGE, mem, right_range);
+          break;
+        case UPDATE_VAR_RIGHT_RANGE_INIT:
+          INIT_RIGHT_RANGE;
+          break;
+        }
+      }
+      MOP_OUT;
+      continue;
+      break;
+
     case OP_FINISH:
       goto finish;
       break;
@@ -3248,7 +3519,7 @@ forward_search_range(regex_t* reg, const UChar* str, const UChar* end, UChar* s,
       }
     }
     else {
-      if (reg->dmax != ONIG_INFINITE_DISTANCE) {
+      if (reg->dmax != INFINITE_LEN) {
         if (p - str < reg->dmax) {
           *low = (UChar* )str;
           if (low_prev)
@@ -3377,7 +3648,7 @@ backward_search_range(regex_t* reg, const UChar* str, const UChar* end,
     }
 
     /* no needs to adjust *high, *high is used as range check only */
-    if (reg->dmax != ONIG_INFINITE_DISTANCE) {
+    if (reg->dmax != INFINITE_LEN) {
       *low  = p - reg->dmax;
       *high = p - reg->dmin;
       *high = onigenc_get_right_adjust_char_head(reg->enc, adjrange, *high);
@@ -3514,7 +3785,7 @@ onig_search(regex_t* reg, const UChar* str, const UChar* end,
 
     end_buf:
       if ((OnigLen )(max_semi_end - str) < reg->anchor_dmin)
-	goto mismatch_no_msa;
+        goto mismatch_no_msa;
 
       if (range > start) {
         if ((OnigLen )(min_semi_end - start) > reg->anchor_dmax) {
@@ -3616,7 +3887,7 @@ onig_search(regex_t* reg, const UChar* str, const UChar* end,
 
       sch_range = (UChar* )range;
       if (reg->dmax != 0) {
-        if (reg->dmax == ONIG_INFINITE_DISTANCE)
+        if (reg->dmax == INFINITE_LEN)
           sch_range = (UChar* )end;
         else {
           sch_range += reg->dmax;
@@ -3627,7 +3898,7 @@ onig_search(regex_t* reg, const UChar* str, const UChar* end,
       if ((end - start) < reg->threshold_len)
         goto mismatch;
 
-      if (reg->dmax != ONIG_INFINITE_DISTANCE) {
+      if (reg->dmax != INFINITE_LEN) {
         do {
           if (! forward_search_range(reg, str, end, s, sch_range,
                                      &low, &high, &low_prev)) goto mismatch;
@@ -3689,7 +3960,7 @@ onig_search(regex_t* reg, const UChar* str, const UChar* end,
       else
         adjrange = (UChar* )end;
 
-      if (reg->dmax != ONIG_INFINITE_DISTANCE &&
+      if (reg->dmax != INFINITE_LEN &&
           (end - range) >= reg->threshold_len) {
         do {
           sch_start = s + reg->dmax;
@@ -3714,7 +3985,7 @@ onig_search(regex_t* reg, const UChar* str, const UChar* end,
 
         sch_start = s;
         if (reg->dmax != 0) {
-          if (reg->dmax == ONIG_INFINITE_DISTANCE)
+          if (reg->dmax == INFINITE_LEN)
             sch_start = (UChar* )end;
           else {
             sch_start += reg->dmax;
diff --git a/src/regint.h b/src/regint.h
index 8da27d2..185f4b6 100644
--- a/src/regint.h
+++ b/src/regint.h
@@ -57,7 +57,7 @@
 /* config */
 /* spec. config */
 #define USE_NAMED_GROUP
-#define USE_SUBEXP_CALL
+#define USE_CALL
 #define USE_BACKREF_WITH_LEVEL        /* \k<name+n>, \k<name-n> */
 #define USE_INSISTENT_CHECK_CAPTURES_STATUS_IN_ENDLESS_REPEAT  /* /(?:()|())*\2/ */
 #define USE_NEWLINE_AT_END_OF_STRING_HAS_EMPTY_LINE     /* /\n$/ =~ "\n" */
@@ -196,6 +196,8 @@ typedef int intptr_t;
 #define CHECK_NULL_RETURN_MEMERR(p)   if (IS_NULL(p)) return ONIGERR_MEMORY
 #define NULL_UCHARP                   ((UChar* )0)
 
+#define INFINITE_LEN        ONIG_INFINITE_DISTANCE
+
 #ifdef PLATFORM_UNALIGNED_WORD_ACCESS
 
 #define PLATFORM_GET_INC(val,p,type) do{\
@@ -211,7 +213,11 @@ typedef int intptr_t;
 } while(0)
 
 /* sizeof(OnigCodePoint) */
-#define WORD_ALIGNMENT_SIZE     SIZEOF_LONG
+#ifdef SIZEOF_SIZE_T
+# define WORD_ALIGNMENT_SIZE     SIZEOF_SIZE_T
+#else
+# define WORD_ALIGNMENT_SIZE     SIZEOF_LONG
+#endif
 
 #define GET_ALIGNMENT_PAD_SIZE(addr,pad_size) do {\
   (pad_size) = WORD_ALIGNMENT_SIZE \
@@ -226,10 +232,20 @@ typedef int intptr_t;
 
 #endif /* PLATFORM_UNALIGNED_WORD_ACCESS */
 
+typedef struct {
+  int num_keeper;
+  int* keepers;
+} RegExt;
+
+#define REG_EXTP(reg)      (RegExt* )((reg)->chain)
+#define REG_EXTPL(reg)     ((reg)->chain)
+
 /* stack pop level */
-#define STACK_POP_LEVEL_FREE        0
-#define STACK_POP_LEVEL_MEM_START   1
-#define STACK_POP_LEVEL_ALL         2
+enum StackPopLevel {
+  STACK_POP_LEVEL_FREE = 0,
+  STACK_POP_LEVEL_MEM_START = 1,
+  STACK_POP_LEVEL_ALL =2
+};
 
 /* optimize flags */
 #define ONIG_OPTIMIZE_NONE              0
@@ -482,11 +498,13 @@ enum OpCode {
 
   OP_BACKREF1,
   OP_BACKREF2,
-  OP_BACKREFN,
-  OP_BACKREFN_IC,
+  OP_BACKREF_N,
+  OP_BACKREF_N_IC,
   OP_BACKREF_MULTI,
   OP_BACKREF_MULTI_IC,
-  OP_BACKREF_WITH_LEVEL,    /* \k<xxx+n>, \k<xxx-n> */
+  OP_BACKREF_WITH_LEVEL,        /* \k<xxx+n>, \k<xxx-n> */
+  OP_BACKREF_CHECK,             /* (?(n)), (?('name')) */
+  OP_BACKREF_CHECK_WITH_LEVEL,  /* (?(n)), (?('name')) */
 
   OP_MEMORY_START,
   OP_MEMORY_START_PUSH,   /* push back-tracker to stack */
@@ -498,6 +516,7 @@ enum OpCode {
   OP_FAIL,               /* pop stack and move */
   OP_JUMP,
   OP_PUSH,
+  OP_PUSH_SUPER,
   OP_POP,
   OP_PUSH_OR_JUMP_EXACT1,  /* if match exact then push, else jump. */
   OP_PUSH_IF_PEEK_NEXT,    /* if match exact then push, else none. */
@@ -512,10 +531,10 @@ enum OpCode {
   OP_EMPTY_CHECK_END_MEMST, /* null loop checker end (with capture status) */
   OP_EMPTY_CHECK_END_MEMST_PUSH, /* with capture status and push check-end */
 
-  OP_PUSH_POS,             /* (?=...)  start */
-  OP_POP_POS,              /* (?=...)  end   */
-  OP_PUSH_POS_NOT,         /* (?!...)  start */
-  OP_FAIL_POS,             /* (?!...)  end   */
+  OP_PREC_READ_START,             /* (?=...)  start */
+  OP_PREC_READ_END,              /* (?=...)  end   */
+  OP_PUSH_PREC_READ_NOT,   /* (?!...)  start */
+  OP_FAIL_PREC_READ_NOT,   /* (?!...)  end   */
   OP_PUSH_STOP_BT,         /* (?>...)  start */
   OP_POP_STOP_BT,          /* (?>...)  end   */
   OP_LOOK_BEHIND,          /* (?<=...) start (no needs end opcode) */
@@ -524,6 +543,8 @@ enum OpCode {
 
   OP_CALL,                 /* \g<name> */
   OP_RETURN,
+  OP_PUSH_SAVE_VAL,
+  OP_UPDATE_VAR,
 
   OP_STATE_CHECK_PUSH,         /* combination explosion check and push */
   OP_STATE_CHECK_PUSH_OR_JUMP, /* check ok -> push, else jump  */
@@ -536,6 +557,20 @@ enum OpCode {
   OP_SET_OPTION          /* set option */
 };
 
+enum SaveType {
+  SAVE_KEEP = 0, /* SAVE S */
+  SAVE_S = 1,
+  SAVE_RIGHT_RANGE = 2,
+};
+
+enum UpdateVarType {
+  UPDATE_VAR_KEEP_FROM_STACK_LAST     = 0,
+  UPDATE_VAR_S_FROM_STACK             = 1,
+  UPDATE_VAR_RIGHT_RANGE_FROM_STACK   = 2,
+  UPDATE_VAR_RIGHT_RANGE_FROM_S_STACK = 3,
+  UPDATE_VAR_RIGHT_RANGE_INIT         = 4,
+};
+
 typedef int RelAddrType;
 typedef int AbsAddrType;
 typedef int LengthType;
@@ -543,6 +578,8 @@ typedef int RepeatNumType;
 typedef int MemNumType;
 typedef short int StateCheckNumType;
 typedef void* PointerType;
+typedef int SaveType;
+typedef int UpdateVarType;
 
 #define SIZE_OPCODE           1
 #define SIZE_RELADDR          sizeof(RelAddrType)
@@ -554,7 +591,8 @@ typedef void* PointerType;
 #define SIZE_OPTION           sizeof(OnigOptionType)
 #define SIZE_CODE_POINT       sizeof(OnigCodePoint)
 #define SIZE_POINTER          sizeof(PointerType)
-
+#define SIZE_SAVE_TYPE        sizeof(SaveType)
+#define SIZE_UPDATE_VAR_TYPE  sizeof(UpdateVarType)
 
 #define GET_RELADDR_INC(addr,p)    PLATFORM_GET_INC(addr,   p, RelAddrType)
 #define GET_ABSADDR_INC(addr,p)    PLATFORM_GET_INC(addr,   p, AbsAddrType)
@@ -564,6 +602,8 @@ typedef void* PointerType;
 #define GET_OPTION_INC(option,p)   PLATFORM_GET_INC(option, p, OnigOptionType)
 #define GET_POINTER_INC(ptr,p)     PLATFORM_GET_INC(ptr,    p, PointerType)
 #define GET_STATE_CHECK_NUM_INC(num,p)  PLATFORM_GET_INC(num, p, StateCheckNumType)
+#define GET_SAVE_TYPE_INC(type,p)       PLATFORM_GET_INC(type, p, SaveType)
+#define GET_UPDATE_VAR_TYPE_INC(type,p) PLATFORM_GET_INC(type, p, UpdateVarType)
 
 /* code point's address must be aligned address. */
 #define GET_CODE_POINT(code,p)   code = *((OnigCodePoint* )(p))
@@ -578,15 +618,16 @@ typedef void* PointerType;
 #define SIZE_OP_ANYCHAR_STAR_PEEK_NEXT (SIZE_OPCODE + 1)
 #define SIZE_OP_JUMP                   (SIZE_OPCODE + SIZE_RELADDR)
 #define SIZE_OP_PUSH                   (SIZE_OPCODE + SIZE_RELADDR)
+#define SIZE_OP_PUSH_SUPER             (SIZE_OPCODE + SIZE_RELADDR)
 #define SIZE_OP_POP                     SIZE_OPCODE
 #define SIZE_OP_PUSH_OR_JUMP_EXACT1    (SIZE_OPCODE + SIZE_RELADDR + 1)
 #define SIZE_OP_PUSH_IF_PEEK_NEXT      (SIZE_OPCODE + SIZE_RELADDR + 1)
 #define SIZE_OP_REPEAT_INC             (SIZE_OPCODE + SIZE_MEMNUM)
 #define SIZE_OP_REPEAT_INC_NG          (SIZE_OPCODE + SIZE_MEMNUM)
-#define SIZE_OP_PUSH_POS                SIZE_OPCODE
-#define SIZE_OP_PUSH_POS_NOT           (SIZE_OPCODE + SIZE_RELADDR)
-#define SIZE_OP_POP_POS                 SIZE_OPCODE
-#define SIZE_OP_FAIL_POS                SIZE_OPCODE
+#define SIZE_OP_PREC_READ_START         SIZE_OPCODE
+#define SIZE_OP_PUSH_PREC_READ_NOT     (SIZE_OPCODE + SIZE_RELADDR)
+#define SIZE_OP_PREC_READ_END           SIZE_OPCODE
+#define SIZE_OP_FAIL_PREC_READ_NOT      SIZE_OPCODE
 #define SIZE_OP_SET_OPTION             (SIZE_OPCODE + SIZE_OPTION)
 #define SIZE_OP_SET_OPTION_PUSH        (SIZE_OPCODE + SIZE_OPTION)
 #define SIZE_OP_FAIL                    SIZE_OPCODE
@@ -605,6 +646,8 @@ typedef void* PointerType;
 #define SIZE_OP_FAIL_LOOK_BEHIND_NOT    SIZE_OPCODE
 #define SIZE_OP_CALL                   (SIZE_OPCODE + SIZE_ABSADDR)
 #define SIZE_OP_RETURN                  SIZE_OPCODE
+#define SIZE_OP_PUSH_SAVE_VAL          (SIZE_OPCODE + SIZE_SAVE_TYPE + SIZE_MEMNUM)
+#define SIZE_OP_UPDATE_VAR             (SIZE_OPCODE + SIZE_UPDATE_VAR_TYPE + SIZE_MEMNUM)
 
 #ifdef USE_COMBINATION_EXPLOSION_CHECK
 #define SIZE_OP_STATE_CHECK            (SIZE_OPCODE + SIZE_STATE_CHECK_NUM)
@@ -664,48 +707,6 @@ typedef void* PointerType;
 #define NCCLASS_CLEAR_NOT(nd)   NCCLASS_FLAG_CLEAR(nd, FLAG_NCCLASS_NOT)
 #define IS_NCCLASS_NOT(nd)      IS_NCCLASS_FLAG_ON(nd, FLAG_NCCLASS_NOT)
 
-typedef intptr_t OnigStackIndex;
-
-typedef struct _OnigStackType {
-  unsigned int type;
-  union {
-    struct {
-      UChar *pcode;      /* byte code position */
-      UChar *pstr;       /* string position */
-      UChar *pstr_prev;  /* previous char position of pstr */
-#ifdef USE_COMBINATION_EXPLOSION_CHECK
-      unsigned int state_check;
-#endif
-    } state;
-    struct {
-      int   count;       /* for OP_REPEAT_INC, OP_REPEAT_INC_NG */
-      UChar *pcode;      /* byte code position (head of repeated target) */
-      int   num;         /* repeat id */
-    } repeat;
-    struct {
-      OnigStackIndex si;     /* index of stack */
-    } repeat_inc;
-    struct {
-      int num;           /* memory num */
-      UChar *pstr;       /* start/end position */
-      /* Following information is set, if this stack type is MEM-START */
-      OnigStackIndex start;  /* prev. info (for backtrack  "(...)*" ) */
-      OnigStackIndex end;    /* prev. info (for backtrack  "(...)*" ) */
-    } mem;
-    struct {
-      int num;           /* null check id */
-      UChar *pstr;       /* start position */
-    } empty_check;
-#ifdef USE_SUBEXP_CALL
-    struct {
-      UChar *ret_addr;   /* byte code position */
-      int    num;        /* null check id */
-      UChar *pstr;       /* string position */
-    } call_frame;
-#endif
-  } u;
-} OnigStackType;
-
 typedef struct {
   void* stack_p;
   int   stack_n;
diff --git a/src/regparse.c b/src/regparse.c
index a5f8e5b..25291c5 100644
--- a/src/regparse.c
+++ b/src/regparse.c
@@ -48,6 +48,11 @@ OnigSyntaxType OnigSyntaxRuby = {
   , ( ONIG_SYN_OP2_QMARK_GROUP_EFFECT |
       ONIG_SYN_OP2_OPTION_RUBY |
       ONIG_SYN_OP2_QMARK_LT_NAMED_GROUP | ONIG_SYN_OP2_ESC_K_NAMED_BACKREF |
+      ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE |
+      ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP |
+      ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE |
+      ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT |
+      ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP |
       ONIG_SYN_OP2_ESC_G_SUBEXP_CALL |
       ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY  |
       ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT |
@@ -179,7 +184,10 @@ static int backref_rel_to_abs(int rel_no, ScanEnv* env)
   }
 }
 
-#define ONOFF(v,f,negative)    (negative) ? ((v) &= ~(f)) : ((v) |= (f))
+#define OPTION_ON(v,f)     ((v) |= (f))
+#define OPTION_OFF(v,f)    ((v) &= ~(f))
+
+#define OPTION_NEGATE(v,f,negative)    (negative) ? ((v) &= ~(f)) : ((v) |= (f))
 
 #define MBCODE_START_POS(enc) \
   (OnigCodePoint )(ONIGENC_MBC_MINLEN(enc) > 1 ? 0 : 0x80)
@@ -301,6 +309,34 @@ strdup_with_null(OnigEncoding enc, UChar* s, UChar* end)
 }
 #endif
 
+static int
+save_entry(ScanEnv* env, enum SaveType type, int* id)
+{
+  int nid = env->save_num;
+
+#if 0
+  if (IS_NULL(env->saves)) {
+    int n = 10;
+    env->saves = (SaveItem* )xmalloc(sizeof(SaveItem) * n);
+    CHECK_NULL_RETURN_MEMERR(env->saves);
+    env->save_alloc_num = n;
+  }
+  else if (env->save_alloc_num <= nid) {
+    int n = env->save_alloc_num * 2;
+    SaveItem* p = (SaveItem* )xrealloc(env->saves, sizeof(SaveItem) * n);
+    CHECK_NULL_RETURN_MEMERR(p);
+    env->saves = p;
+    env->save_alloc_num = n;
+  }
+
+  env->saves[nid].type = type;
+#endif
+
+  env->save_num++;
+  *id = nid;
+  return 0;
+}
+
 /* scan pattern methods */
 #define PEND_VALUE   0
 
@@ -990,7 +1026,7 @@ scan_env_clear(ScanEnv* env)
   env->error_end  = (UChar* )NULL;
   env->num_call   = 0;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   env->unset_addr_list = NULL;
   env->has_call_zero   = 0;
 #endif
@@ -1011,6 +1047,10 @@ scan_env_clear(ScanEnv* env)
   env->has_recursion       = 0;
 #endif
   env->parse_depth         = 0;
+  env->keep_num            = 0;
+  env->save_num            = 0;
+  env->save_alloc_num      = 0;
+  env->saves               = 0;
 }
 
 static int
@@ -1075,7 +1115,7 @@ onig_node_free(Node* node)
 #endif
 
   switch (NODE_TYPE(node)) {
-  case NODE_STR:
+  case NODE_STRING:
     if (STR_(node)->capa != 0 &&
         IS_NOT_NULL(STR_(node)->s) && STR_(node)->s != STR_(node)->buf) {
       xfree(STR_(node)->s);
@@ -1103,13 +1143,25 @@ onig_node_free(Node* node)
     }
     break;
 
-  case NODE_BREF:
-    if (IS_NOT_NULL(BREF_(node)->back_dynamic))
-      xfree(BREF_(node)->back_dynamic);
+  case NODE_BACKREF:
+    if (IS_NOT_NULL(BACKREF_(node)->back_dynamic))
+      xfree(BACKREF_(node)->back_dynamic);
     break;
 
-  case NODE_QUANT:
   case NODE_ENCLOSURE:
+    if (NODE_BODY(node))
+      onig_node_free(NODE_BODY(node));
+
+    {
+      EnclosureNode* en = ENCLOSURE_(node);
+      if (en->type == ENCLOSURE_IF_ELSE) {
+        onig_node_free(en->te.Then);
+        onig_node_free(en->te.Else);
+      }
+    }
+    break;
+
+  case NODE_QUANT:
   case NODE_ANCHOR:
     if (NODE_BODY(node))
       onig_node_free(NODE_BODY(node));
@@ -1117,12 +1169,35 @@ onig_node_free(Node* node)
 
   case NODE_CTYPE:
   case NODE_CALL:
+  case NODE_GIMMICK:
     break;
   }
 
   xfree(node);
 }
 
+static void
+cons_node_free_alone(Node* node)
+{
+  NODE_CAR(node) = 0;
+  NODE_CDR(node) = 0;
+  onig_node_free(node);
+}
+
+extern void
+list_node_free_not_car(Node* node)
+{
+  Node* next_node;
+
+ start:
+  if (IS_NULL(node)) return;
+
+  next_node = NODE_CDR(node);
+  xfree(node);
+  node = next_node;
+  goto start;
+}
+
 static Node*
 node_new(void)
 {
@@ -1154,7 +1229,7 @@ node_new_cclass(void)
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_CCLASS);
+  NODE_SET_TYPE(node, NODE_CCLASS);
   initialize_cclass(CCLASS_(node));
   return node;
 }
@@ -1165,19 +1240,61 @@ node_new_ctype(int type, int not)
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_CTYPE);
+  NODE_SET_TYPE(node, NODE_CTYPE);
   CTYPE_(node)->ctype = type;
   CTYPE_(node)->not   = not;
   return node;
 }
 
 static Node*
+node_new_anychar(void)
+{
+  Node* node = node_new_ctype(CTYPE_ANYCHAR, 0);
+  return node;
+}
+
+static Node*
+node_new_anychar_with_fixed_option(OnigOptionType option)
+{
+  CtypeNode* ct;
+  Node* node;
+
+  node = node_new_anychar();
+  ct = CTYPE_(node);
+  ct->options = option;
+  NODE_STATUS_ADD(node, NST_FIXED_OPTION);
+  return node;
+}
+
+static int
+node_new_no_newline(Node** node, ScanEnv* env)
+{
+  Node* n;
+
+  n = node_new_anychar_with_fixed_option(ONIG_OPTION_NONE);
+  CHECK_NULL_RETURN_MEMERR(n);
+  *node = n;
+  return 0;
+}
+
+static int
+node_new_true_anychar(Node** node, ScanEnv* env)
+{
+  Node* n;
+
+  n = node_new_anychar_with_fixed_option(ONIG_OPTION_MULTILINE);
+  CHECK_NULL_RETURN_MEMERR(n);
+  *node = n;
+  return 0;
+}
+
+static Node*
 node_new_list(Node* left, Node* right)
 {
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_LIST);
+  NODE_SET_TYPE(node, NODE_LIST);
   NODE_CAR(node)  = left;
   NODE_CDR(node) = right;
   return node;
@@ -1213,19 +1330,65 @@ onig_node_new_alt(Node* left, Node* right)
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_ALT);
+  NODE_SET_TYPE(node, NODE_ALT);
   NODE_CAR(node)  = left;
   NODE_CDR(node) = right;
   return node;
 }
 
+static Node*
+make_list_or_alt(NodeType type, int n, Node* ns[])
+{
+  Node* r;
+
+  if (n <= 0) return NULL_NODE;
+
+  if (n == 1) {
+    r = node_new();
+    CHECK_NULL_RETURN(r);
+    NODE_SET_TYPE(r, type);
+    NODE_CAR(r) = ns[0];
+    NODE_CDR(r) = NULL_NODE;
+  }
+  else {
+    Node* right;
+
+    r = node_new();
+    CHECK_NULL_RETURN(r);
+
+    right = make_list_or_alt(type, n - 1, ns + 1);
+    if (IS_NULL(right)) {
+      onig_node_free(r);
+      return NULL_NODE;
+    }
+
+    NODE_SET_TYPE(r, type);
+    NODE_CAR(r) = ns[0];
+    NODE_CDR(r) = right;
+  }
+
+  return r;
+}
+
+static Node*
+make_list(int n, Node* ns[])
+{
+  return make_list_or_alt(NODE_LIST, n, ns);
+}
+
+static Node*
+make_alt(int n, Node* ns[])
+{
+  return make_list_or_alt(NODE_ALT, n, ns);
+}
+
 extern Node*
 onig_node_new_anchor(int type)
 {
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_ANCHOR);
+  NODE_SET_TYPE(node, NODE_ANCHOR);
   ANCHOR_(node)->type     = type;
   ANCHOR_(node)->char_len = -1;
   return node;
@@ -1243,16 +1406,16 @@ node_new_backref(int back_num, int* backrefs, int by_name,
 
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_BREF);
-  BREF_(node)->back_num = back_num;
-  BREF_(node)->back_dynamic = (int* )NULL;
+  NODE_SET_TYPE(node, NODE_BACKREF);
+  BACKREF_(node)->back_num = back_num;
+  BACKREF_(node)->back_dynamic = (int* )NULL;
   if (by_name != 0)
     NODE_STATUS_ADD(node, NST_BY_NAME);
 
 #ifdef USE_BACKREF_WITH_LEVEL
   if (exist_level != 0) {
     NODE_STATUS_ADD(node, NST_NEST_LEVEL);
-    BREF_(node)->nest_level  = nest_level;
+    BACKREF_(node)->nest_level  = nest_level;
   }
 #endif
 
@@ -1266,7 +1429,7 @@ node_new_backref(int back_num, int* backrefs, int by_name,
 
   if (back_num <= NODE_BACKREFS_SIZE) {
     for (i = 0; i < back_num; i++)
-      BREF_(node)->back_static[i] = backrefs[i];
+      BACKREF_(node)->back_static[i] = backrefs[i];
   }
   else {
     int* p = (int* )xmalloc(sizeof(int) * back_num);
@@ -1274,21 +1437,41 @@ node_new_backref(int back_num, int* backrefs, int by_name,
       onig_node_free(node);
       return NULL;
     }
-    BREF_(node)->back_dynamic = p;
+    BACKREF_(node)->back_dynamic = p;
     for (i = 0; i < back_num; i++)
       p[i] = backrefs[i];
   }
   return node;
 }
 
-#ifdef USE_SUBEXP_CALL
+static Node*
+node_new_backref_checker(int back_num, int* backrefs, int by_name,
+#ifdef USE_BACKREF_WITH_LEVEL
+		 int exist_level, int nest_level,
+#endif
+		 ScanEnv* env)
+{
+  Node* node;
+
+  node = node_new_backref(back_num, backrefs, by_name,
+#ifdef USE_BACKREF_WITH_LEVEL
+                          exist_level, nest_level,
+#endif
+                          env);
+  CHECK_NULL_RETURN(node);
+
+  NODE_STATUS_ADD(node, NST_CHECKER);
+  return node;
+}
+
+#ifdef USE_CALL
 static Node*
 node_new_call(UChar* name, UChar* name_end, int gnum, int by_number)
 {
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_CALL);
+  NODE_SET_TYPE(node, NODE_CALL);
   CALL_(node)->by_number   = by_number;
   CALL_(node)->name        = name;
   CALL_(node)->name_end    = name_end;
@@ -1304,7 +1487,7 @@ node_new_quantifier(int lower, int upper, int by_number)
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_QUANT);
+  NODE_SET_TYPE(node, NODE_QUANT);
   QUANT_(node)->lower  = lower;
   QUANT_(node)->upper  = upper;
   QUANT_(node)->greedy = 1;
@@ -1328,7 +1511,7 @@ node_new_enclosure(int type)
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_ENCLOSURE);
+  NODE_SET_TYPE(node, NODE_ENCLOSURE);
   ENCLOSURE_(node)->type = type;
 
   switch (type) {
@@ -1340,11 +1523,16 @@ node_new_enclosure(int type)
     break;
 
   case ENCLOSURE_OPTION:
-    ENCLOSURE_(node)->o.option =  0;
+    ENCLOSURE_(node)->o.options =  0;
     break;
 
   case ENCLOSURE_STOP_BACKTRACK:
     break;
+
+  case ENCLOSURE_IF_ELSE:
+    ENCLOSURE_(node)->te.Then = 0;
+    ENCLOSURE_(node)->te.Else = 0;
+    break;
   }
 
   ENCLOSURE_(node)->opt_count = 0;
@@ -1358,7 +1546,20 @@ onig_node_new_enclosure(int type)
 }
 
 static Node*
-node_new_enclosure_memory(int is_named)
+node_new_enclosure_if_else(Node* cond, Node* Then, Node* Else)
+{
+  Node* n;
+  n = node_new_enclosure(ENCLOSURE_IF_ELSE);
+  CHECK_NULL_RETURN(n);
+
+  NODE_BODY(n) = cond;
+  ENCLOSURE_(n)->te.Then = Then;
+  ENCLOSURE_(n)->te.Else = Else;
+  return n;
+}
+
+static Node*
+node_new_memory(int is_named)
 {
   Node* node = node_new_enclosure(ENCLOSURE_MEMORY);
   CHECK_NULL_RETURN(node);
@@ -1373,10 +1574,395 @@ node_new_option(OnigOptionType option)
 {
   Node* node = node_new_enclosure(ENCLOSURE_OPTION);
   CHECK_NULL_RETURN(node);
-  ENCLOSURE_(node)->o.option = option;
+  ENCLOSURE_(node)->o.options = option;
   return node;
 }
 
+static int
+node_new_fail(Node** node, ScanEnv* env)
+{
+  *node = node_new();
+  CHECK_NULL_RETURN_MEMERR(*node);
+
+  NODE_SET_TYPE(*node, NODE_GIMMICK);
+  GIMMICK_(*node)->type = GIMMICK_FAIL;
+  return ONIG_NORMAL;
+}
+
+static int
+node_new_save_gimmick(Node** node, enum SaveType save_type, ScanEnv* env)
+{
+  int id;
+  int r;
+
+  r = save_entry(env, save_type, &id);
+  if (r != ONIG_NORMAL) return r;
+
+  *node = node_new();
+  CHECK_NULL_RETURN_MEMERR(*node);
+
+  NODE_SET_TYPE(*node, NODE_GIMMICK);
+  GIMMICK_(*node)->id   = id;
+  GIMMICK_(*node)->type = GIMMICK_SAVE;
+  GIMMICK_(*node)->detail_type = (int )save_type;
+
+  return ONIG_NORMAL;
+}
+
+static int
+node_new_update_var_gimmick(Node** node, enum UpdateVarType update_var_type,
+                            int id, ScanEnv* env)
+{
+  *node = node_new();
+  CHECK_NULL_RETURN_MEMERR(*node);
+
+  NODE_SET_TYPE(*node, NODE_GIMMICK);
+  GIMMICK_(*node)->id   = id;
+  GIMMICK_(*node)->type = GIMMICK_UPDATE_VAR;
+  GIMMICK_(*node)->detail_type = (int )update_var_type;
+
+  return ONIG_NORMAL;
+}
+
+static int
+node_new_keep(Node** node, ScanEnv* env)
+{
+  int r;
+
+  r = node_new_save_gimmick(node, SAVE_KEEP, env);
+  if (r != 0) return r;
+
+  env->keep_num++;
+  return ONIG_NORMAL;
+}
+
+static int
+make_absent_engine(Node** node, int pre_save_right_id, Node* absent,
+                   Node* step_one, int lower, int upper, int possessive,
+                   int is_range_cutter, ScanEnv* env)
+{
+  int r;
+  int i;
+  int id;
+  Node* x;
+  Node* ns[4];
+
+  for (i = 0; i < 4; i++) ns[i] = NULL_NODE;
+
+  ns[1] = absent;
+  ns[3] = step_one; // for err
+  r = node_new_save_gimmick(&ns[0], SAVE_S, env);
+  if (r != 0) goto err;
+
+  id = GIMMICK_(ns[0])->id;
+  r = node_new_update_var_gimmick(&ns[2], UPDATE_VAR_RIGHT_RANGE_FROM_S_STACK,
+                                  id, env);
+  if (r != 0) goto err;
+
+  r = node_new_fail(&ns[3], env);
+  if (r != 0) goto err;
+
+  x = make_list(4, ns);
+  if (IS_NULL(x)) goto err;
+
+  ns[0] = x;
+  ns[1] = step_one;
+  ns[2] = ns[3] = NULL_NODE;
+
+  x = make_alt(2, ns);
+  if (IS_NULL(x)) goto err;
+
+  ns[0] = x;
+
+  x = node_new_quantifier(lower, upper, 0);
+  if (IS_NULL(x)) goto err;
+
+  NODE_BODY(x) = ns[0];
+  ns[0] = x;
+
+  if (possessive != 0) {
+    x = node_new_enclosure(ENCLOSURE_STOP_BACKTRACK);
+    if (IS_NULL(x)) goto err;
+
+    NODE_BODY(x) = ns[0];
+    ns[0] = x;
+  }
+
+  r = node_new_update_var_gimmick(&ns[1], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
+                                  pre_save_right_id, env);
+  if (r != 0) goto err;
+
+  r = node_new_fail(&ns[2], env);
+  if (r != 0) goto err;
+
+  x = make_list(2, ns + 1);
+  if (IS_NULL(x)) goto err;
+
+  ns[1] = x; ns[2] = NULL_NODE;
+
+  x = make_alt(2, ns);
+  if (IS_NULL(x)) goto err;
+
+  if (is_range_cutter != 0)
+    NODE_STATUS_ADD(x, NST_SUPER);
+
+  *node = x;
+  return ONIG_NORMAL;
+
+ err:
+  for (i = 0; i < 4; i++) onig_node_free(ns[i]);
+  return r;
+}
+
+static int
+make_absent_tail(Node** node1, Node** node2, int pre_save_right_id,
+                 ScanEnv* env)
+{
+  int r;
+  int id;
+  Node* save;
+  Node* x;
+  Node* ns[2];
+
+  *node1 = *node2 = NULL_NODE;
+  save = ns[0] = ns[1] = NULL_NODE;
+
+  r = node_new_save_gimmick(&save, SAVE_RIGHT_RANGE, env);
+  if (r != 0) goto err;
+
+  id = GIMMICK_(save)->id;
+  r = node_new_update_var_gimmick(&ns[0], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
+                                  id, env);
+  if (r != 0) goto err;
+
+  r = node_new_fail(&ns[1], env);
+  if (r != 0) goto err;
+
+  x = make_list(2, ns);
+  if (IS_NULL(x)) goto err;
+
+  ns[0] = NULL_NODE; ns[1] = x;
+
+  r = node_new_update_var_gimmick(&ns[0], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
+                                  pre_save_right_id, env);
+  if (r != 0) goto err;
+
+  x = make_alt(2, ns);
+  if (IS_NULL(x)) goto err;
+
+  *node1 = save;
+  *node2 = x;
+  return ONIG_NORMAL;
+
+ err:
+  onig_node_free(save);
+  onig_node_free(ns[0]);
+  onig_node_free(ns[1]);
+  return r;
+}
+
+static int
+is_simple_one_char_repeat(Node* node, Node** rquant, Node** rbody,
+                          int* is_possessive, ScanEnv* env)
+{
+  Node* quant;
+  Node* body;
+
+  *rquant = *rbody = 0;
+  *is_possessive = 0;
+
+  if (NODE_TYPE(node) == NODE_QUANT) {
+    quant = node;
+  }
+  else {
+    if (NODE_TYPE(node) == NODE_ENCLOSURE) {
+      EnclosureNode* en = ENCLOSURE_(node);
+      if (en->type == ENCLOSURE_STOP_BACKTRACK) {
+        *is_possessive = 1;
+        quant = NODE_ENCLOSURE_BODY(en);
+        if (NODE_TYPE(quant) != NODE_QUANT)
+          return 0;
+      }
+      else
+        return 0;
+    }
+    else
+      return 0;
+  }
+
+  body = NODE_BODY(quant);
+  switch (NODE_TYPE(body)) {
+  case NODE_STRING:
+    {
+      int len;
+      StrNode* sn = STR_(body);
+      UChar *s = sn->s;
+
+      len = 0;
+      while (s < sn->end) {
+        s += enclen(env->enc, s);
+        len++;
+      }
+      if (len != 1)
+        return 0;
+    }
+
+  case NODE_CCLASS:
+    break;
+
+  default:
+    return 0;
+    break;
+  }
+
+  if (node != quant) {
+    NODE_BODY(node) = 0;
+    onig_node_free(node);
+  }
+  NODE_BODY(quant) = NULL_NODE;
+  *rquant = quant;
+  *rbody  = body;
+  return 1;
+}
+
+static int
+make_absent_tree_for_simple_one_char_repeat(Node** node, Node* absent, Node* quant,
+                                            Node* body, int possessive, ScanEnv* env)
+{
+  int r;
+  int i;
+  int id1;
+  int lower, upper;
+  Node* x;
+  Node* ns[4];
+
+  *node = NULL_NODE;
+  r = ONIGERR_MEMORY;
+  ns[0] = ns[1] = NULL_NODE;
+  ns[2] = body, ns[3] = absent;
+
+  lower = QUANT_(quant)->lower;
+  upper = QUANT_(quant)->upper;
+  onig_node_free(quant);
+
+  r = node_new_save_gimmick(&ns[0], SAVE_RIGHT_RANGE, env);
+  if (r != 0) goto err;
+
+  id1 = GIMMICK_(ns[0])->id;
+
+  r = make_absent_engine(&ns[1], id1, absent, body, lower, upper, possessive,
+                         0, env);
+  if (r != 0) goto err;
+
+  ns[2] = ns[3] = NULL_NODE;
+
+  r = make_absent_tail(&ns[2], &ns[3], id1, env);
+  if (r != 0) goto err;
+
+  x = make_list(4, ns);
+  if (IS_NULL(x)) goto err;
+
+  *node = x;
+  return ONIG_NORMAL;
+
+ err:
+  for (i = 0; i < 4; i++) onig_node_free(ns[i]);
+  return r;
+}
+
+static int
+make_absent_tree(Node** node, Node* absent, Node* expr, int is_range_cutter,
+                 ScanEnv* env)
+{
+  int r;
+  int i;
+  int id1, id2;
+  int possessive;
+  Node* x;
+  Node* ns[7];
+
+  r = ONIGERR_MEMORY;
+  for (i = 0; i < 7; i++) ns[i] = NULL_NODE;
+  ns[4] = expr; ns[5] = absent;
+
+  if (is_range_cutter == 0) {
+    Node* quant;
+    Node* body;
+
+    if (expr == NULL_NODE) {
+      /* default expr \O* */
+      quant = node_new_quantifier(0, REPEAT_INFINITE, 0);
+      if (IS_NULL(quant)) goto err;
+
+      r = node_new_true_anychar(&body, env);
+      if (r != 0) {
+        onig_node_free(quant);
+        goto err;
+      }
+      possessive = 0;
+      goto simple;
+    }
+    else {
+      if (is_simple_one_char_repeat(expr, &quant, &body, &possessive, env)) {
+      simple:
+        r = make_absent_tree_for_simple_one_char_repeat(node, absent, quant,
+                                                        body, possessive, env);
+        if (r != 0) {
+          ns[4] = NULL_NODE;
+          onig_node_free(quant);
+          onig_node_free(body);
+          goto err;
+        }
+
+        return ONIG_NORMAL;
+      }
+    }
+  }
+
+  r = node_new_save_gimmick(&ns[0], SAVE_RIGHT_RANGE, env);
+  if (r != 0) goto err;
+
+  id1 = GIMMICK_(ns[0])->id;
+
+  r = node_new_save_gimmick(&ns[1], SAVE_S, env);
+  if (r != 0) goto err;
+
+  id2 = GIMMICK_(ns[1])->id;
+
+  r = node_new_true_anychar(&ns[3], env);
+  if (r != 0) goto err;
+
+  possessive = 1;
+  r = make_absent_engine(&ns[2], id1, absent, ns[3], 0, REPEAT_INFINITE,
+                         possessive, is_range_cutter, env);
+  if (r != 0) goto err;
+
+  ns[3] = NULL_NODE;
+  ns[5] = NULL_NODE;
+
+  r = node_new_update_var_gimmick(&ns[3], UPDATE_VAR_S_FROM_STACK, id2, env);
+  if (r != 0) goto err;
+
+  if (is_range_cutter != 0) {
+    x = make_list(4, ns);
+    if (IS_NULL(x)) goto err;
+  }
+  else {
+    r = make_absent_tail(&ns[5], &ns[6], id1, env);
+    if (r != 0) goto err;
+  
+    x = make_list(7, ns);
+    if (IS_NULL(x)) goto err;
+  }
+
+  *node = x;
+  return ONIG_NORMAL;
+
+ err:
+  for (i = 0; i < 7; i++) onig_node_free(ns[i]);
+  return r;  
+}
+
 extern int
 onig_node_str_cat(Node* node, const UChar* s, const UChar* end)
 {
@@ -1385,9 +1971,9 @@ onig_node_str_cat(Node* node, const UChar* s, const UChar* end)
   if (addlen > 0) {
     int len  = STR_(node)->end - STR_(node)->s;
 
-    if (STR_(node)->capa > 0 || (len + addlen > NODE_STR_BUF_SIZE - 1)) {
+    if (STR_(node)->capa > 0 || (len + addlen > NODE_STRING_BUF_SIZE - 1)) {
       UChar* p;
-      int capa = len + addlen + NODE_STR_MARGIN;
+      int capa = len + addlen + NODE_STRING_MARGIN;
 
       if (capa <= STR_(node)->capa) {
         onig_strcpy(STR_(node)->s + len, s, end);
@@ -1432,7 +2018,7 @@ node_str_cat_char(Node* node, UChar c)
 extern void
 onig_node_conv_to_str_node(Node* node, int flag)
 {
-  SET_NODE_TYPE(node, NODE_STR);
+  NODE_SET_TYPE(node, NODE_STRING);
   STR_(node)->flag = flag;
   STR_(node)->capa = 0;
   STR_(node)->s    = STR_(node)->buf;
@@ -1459,7 +2045,7 @@ node_new_str(const UChar* s, const UChar* end)
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
-  SET_NODE_TYPE(node, NODE_STR);
+  NODE_SET_TYPE(node, NODE_STRING);
   STR_(node)->capa = 0;
   STR_(node)->flag = 0;
   STR_(node)->s    = STR_(node)->buf;
@@ -1481,7 +2067,7 @@ static Node*
 node_new_str_raw(UChar* s, UChar* end)
 {
   Node* node = node_new_str(s, end);
-  NSTRING_SET_RAW(node);
+  NODE_STRING_SET_RAW(node);
   return node;
 }
 
@@ -1511,7 +2097,7 @@ str_node_split_last_char(StrNode* sn, OnigEncoding enc)
     if (p && p > sn->s) { /* can be split. */
       n = node_new_str(p, sn->end);
       if ((sn->flag & STRING_RAW) != 0)
-        NSTRING_SET_RAW(n);
+        NODE_STRING_SET_RAW(n);
 
       sn->end = (UChar* )p;
     }
@@ -1532,7 +2118,7 @@ str_node_can_be_split(StrNode* sn, OnigEncoding enc)
 static int
 node_str_head_pad(StrNode* sn, int num, UChar val)
 {
-  UChar buf[NODE_STR_BUF_SIZE];
+  UChar buf[NODE_STRING_BUF_SIZE];
   int i, len;
 
   len = sn->end - sn->s;
@@ -2090,6 +2676,7 @@ is_invalid_quantifier_target(Node* node)
 {
   switch (NODE_TYPE(node)) {
   case NODE_ANCHOR:
+  case NODE_GIMMICK:
     return 1;
     break;
 
@@ -2212,6 +2799,56 @@ onig_reduce_nested_quantifier(Node* pnode, Node* cnode)
   onig_node_free(cnode);
 }
 
+static int
+node_new_general_newline(Node** node, ScanEnv* env)
+{
+  int r;
+  int dlen, alen;
+  UChar buf[ONIGENC_CODE_TO_MBC_MAXLEN * 2];
+  Node* crnl;
+  Node* ncc;
+  Node* x;
+  CClassNode* cc;
+
+  dlen = ONIGENC_CODE_TO_MBC(env->enc, 0x0d, buf);
+  if (dlen < 0) return dlen;
+  alen = ONIGENC_CODE_TO_MBC(env->enc, 0x0a, buf + dlen);
+  if (alen < 0) return alen;
+
+  crnl = node_new_str_raw(buf, buf + dlen + alen);
+  CHECK_NULL_RETURN_MEMERR(crnl);
+
+  ncc = node_new_cclass();
+  if (IS_NULL(ncc)) goto err2;
+
+  cc = CCLASS_(ncc);
+  if (dlen == 1) {
+    bitset_set_range(cc->bs, 0x0a, 0x0d);
+  }
+  else {
+    r = add_code_range(&(cc->mbuf), env, 0x0a, 0x0d);
+    if (r != 0) {
+    err1:
+      onig_node_free(ncc);
+    err2:
+      onig_node_free(crnl);
+      return ONIGERR_MEMORY;
+    }
+  }
+
+  if (ONIGENC_IS_UNICODE_ENCODING(env->enc)) {
+    r = add_code_range(&(cc->mbuf), env, 0x85, 0x85);
+    if (r != 0) goto err1;
+    r = add_code_range(&(cc->mbuf), env, 0x2028, 0x2029);
+    if (r != 0) goto err1;
+  }
+
+  x = node_new_enclosure_if_else(crnl, 0, ncc);
+  if (IS_NULL(x)) goto err1;
+
+  *node = x;
+  return 0;
+}
 
 enum TokenSyms {
   TK_EOT      = 0,   /* end of token */
@@ -2233,6 +2870,11 @@ enum TokenSyms {
   TK_CC_OPEN,
   TK_QUOTE_OPEN,
   TK_CHAR_PROPERTY,    /* \p{...}, \P{...} */
+  TK_KEEP,             /* \K */
+  TK_GENERAL_NEWLINE,  /* \R */
+  TK_NO_NEWLINE,       /* \N */
+  TK_TRUE_ANYCHAR,     /* \O */
+
   /* in cc */
   TK_CC_CLOSE,
   TK_CC_RANGE,
@@ -2452,8 +3094,9 @@ static OnigCodePoint
 get_name_end_code_point(OnigCodePoint start)
 {
   switch (start) {
-  case '<':  return (OnigCodePoint )'>'; break;
+  case '<':  return (OnigCodePoint )'>';  break;
   case '\'': return (OnigCodePoint )'\''; break;
+  case '(':  return (OnigCodePoint )')';  break;
   default:
     break;
   }
@@ -2706,7 +3349,7 @@ fetch_name(OnigCodePoint start_code, UChar** src, UChar* end,
 
     if (c != end_code) {
       r = ONIGERR_INVALID_GROUP_NAME;
-      name_end = end;
+      goto err;
     }
 
     if (*num_type != IS_NOT_NUM) {
@@ -3378,6 +4021,26 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
       tok->u.prop.not   = 1;
       break;
 
+    case 'K':
+      if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP)) break;
+      tok->type = TK_KEEP;
+      break;
+
+    case 'R':
+      if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE)) break;
+      tok->type = TK_GENERAL_NEWLINE;
+      break;
+
+    case 'N':
+      if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT)) break;
+      tok->type = TK_NO_NEWLINE;
+      break;
+
+    case 'O':
+      if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT)) break;
+      tok->type = TK_TRUE_ANYCHAR;
+      break;
+
     case 'A':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_AZ_BUF_ANCHOR)) break;
     begin_buf:
@@ -3561,7 +4224,7 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
           if (r == 1) tok->u.backref.exist_level = 1;
           else        tok->u.backref.exist_level = 0;
 #else
-          r = fetch_name(&p, end, &name_end, env, &back_num, &num_type, 1);
+          r = fetch_name(c, &p, end, &name_end, env, &back_num, &num_type, 1);
 #endif
           if (r < 0) return r;
 
@@ -3616,7 +4279,7 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
       break;
 #endif
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     case 'g':
       if (!PEND && IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_G_SUBEXP_CALL)) {
         PFETCH(c);
@@ -3815,14 +4478,14 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
     case '^':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_LINE_ANCHOR)) break;
       tok->type = TK_ANCHOR;
-      tok->u.subtype = (IS_SINGLELINE(env->option)
+      tok->u.subtype = (IS_SINGLELINE(env->options)
 			? ANCHOR_BEGIN_BUF : ANCHOR_BEGIN_LINE);
       break;
 
     case '$':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_LINE_ANCHOR)) break;
       tok->type = TK_ANCHOR;
-      tok->u.subtype = (IS_SINGLELINE(env->option)
+      tok->u.subtype = (IS_SINGLELINE(env->options)
 			? ANCHOR_SEMI_END_BUF : ANCHOR_END_LINE);
       break;
 
@@ -3837,7 +4500,7 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
       break;
 
     case '#':
-      if (IS_EXTEND(env->option)) {
+      if (IS_EXTEND(env->options)) {
         while (!PEND) {
           PFETCH(c);
           if (ONIGENC_IS_CODE_NEWLINE(enc, c))
@@ -3849,7 +4512,7 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
       break;
 
     case ' ': case '\t': case '\n': case '\r': case '\f':
-      if (IS_EXTEND(env->option))
+      if (IS_EXTEND(env->options))
         goto start;
       break;
 
@@ -4640,7 +5303,7 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
   *np = NULL;
   if (PEND) return ONIGERR_END_PATTERN_WITH_UNMATCHED_PARENTHESIS;
 
-  option = env->option;
+  option = env->options;
   if (PPEEK_IS('?') &&
       IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_GROUP_EFFECT)) {
     PINC;
@@ -4711,7 +5374,7 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
 
           r = name_add(env->reg, name, name_end, num, env);
           if (r != 0) return r;
-          *np = node_new_enclosure_memory(1);
+          *np = node_new_memory(1);
           CHECK_NULL_RETURN_MEMERR(*np);
           ENCLOSURE_(*np)->m.regnum = num;
           if (list_capture != 0)
@@ -4729,6 +5392,259 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
 #endif
       break;
 
+    case '~':
+      if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP)) {
+        Node* absent;
+        Node* expr;
+        int head_bar;
+        int is_range_cutter;
+
+        if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
+
+        if (PPEEK_IS('|')) { // (?~|generator|absent)
+          PINC;
+          if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
+
+          head_bar = 1;
+          if (PPEEK_IS(')')) { // (?~|)  : absent clear
+            PINC;
+            r = node_new_update_var_gimmick(np, UPDATE_VAR_RIGHT_RANGE_INIT,
+                                            0, env);
+            if (r != 0) return r;
+            goto end;
+          }
+        }
+        else
+          head_bar = 0;
+
+        r = fetch_token(tok, &p, end, env);
+        if (r < 0) return r;
+        r = parse_subexp(&absent, tok, term, &p, end, env);
+        if (r < 0) {
+          onig_node_free(absent);
+          return r;
+        }
+
+        expr = NULL_NODE;
+        is_range_cutter = 0;
+        if (head_bar != 0) {
+          Node* top = absent;
+          if (NODE_TYPE(top) != NODE_ALT || IS_NULL(NODE_CDR(top))) {
+            expr = NULL_NODE;
+            is_range_cutter = 1;
+            //return ONIGERR_INVALID_ABSENT_GROUP_GENERATOR_PATTERN;
+          }
+          else {
+            absent = NODE_CAR(top);
+            expr   = NODE_CDR(top);
+            NODE_CAR(top) = NULL_NODE;
+            NODE_CDR(top) = NULL_NODE;
+            onig_node_free(top);
+            if (IS_NULL(NODE_CDR(expr))) {
+              top = expr;
+              expr = NODE_CAR(top);
+              NODE_CAR(top) = NULL_NODE;
+              onig_node_free(top);
+            }
+          }
+        }
+
+        r = make_absent_tree(np, absent, expr, is_range_cutter, env);
+        if (r != 0) {
+          return r;
+        }
+        goto end;
+      }
+      else {
+        return ONIGERR_UNDEFINED_GROUP_OPTION;
+      }
+      break;
+
+    case '(':
+      /* (?()...) */
+      if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE)) {
+        UChar *prev;
+        Node* condition;
+        int condition_is_checker;
+
+        if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
+        PFETCH(c);
+        if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
+
+        if (ONIGENC_IS_CODE_DIGIT(enc, c)
+            || c == '-' || c == '+' || c == '<' || c == '\'') {
+          UChar* name_end;
+          int back_num;
+          int exist_level;
+          int level;
+          enum REF_NUM num_type;
+          int is_enclosed;
+
+          is_enclosed = (c == '<' || c == '\'') ? 1 : 0;
+          if (! is_enclosed)
+            PUNFETCH;
+          prev = p;
+          exist_level = 0;
+#ifdef USE_BACKREF_WITH_LEVEL
+          name_end = NULL_UCHARP; /* no need. escape gcc warning. */
+          r = fetch_name_with_level(
+                    (OnigCodePoint )(is_enclosed != 0 ? c : '('),
+                    &p, end, &name_end,
+                    env, &back_num, &level, &num_type);
+          if (r == 1) exist_level = 1;
+#else
+          r = fetch_name((OnigCodePoint )(is_enclosed != 0 ? c : '('),
+                         &p, end, &name_end, env, &back_num, &num_type, 1);
+#endif
+          if (r < 0) {
+            if (is_enclosed == 0) {
+              goto any_condition;
+            }
+            else
+              return r;
+          }
+
+          condition_is_checker = 1;
+          if (num_type != IS_NOT_NUM) {
+            if (num_type == IS_REL_NUM) {
+              back_num = backref_rel_to_abs(back_num, env);
+            }
+            if (back_num <= 0)
+              return ONIGERR_INVALID_BACKREF;
+
+            if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_STRICT_CHECK_BACKREF)) {
+              if (back_num > env->num_mem ||
+                  IS_NULL(SCANENV_MEMENV(env)[back_num].node))
+                return ONIGERR_INVALID_BACKREF;
+            }
+
+            condition = node_new_backref_checker(1, &back_num, 0,
+#ifdef USE_BACKREF_WITH_LEVEL
+                                                 exist_level, level,
+#endif
+                                                 env);
+          }
+          else {
+            int num;
+            int* backs;
+
+            num = onig_name_to_group_numbers(env->reg, prev, name_end, &backs);
+            if (num <= 0) {
+              onig_scan_env_set_error_string(env,
+                        ONIGERR_UNDEFINED_NAME_REFERENCE, prev, name_end);
+              return ONIGERR_UNDEFINED_NAME_REFERENCE;
+            }
+            if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_STRICT_CHECK_BACKREF)) {
+              int i;
+              for (i = 0; i < num; i++) {
+                if (backs[i] > env->num_mem ||
+                    IS_NULL(SCANENV_MEMENV(env)[backs[i]].node))
+                  return ONIGERR_INVALID_BACKREF;
+              }
+            }
+
+            condition = node_new_backref_checker(num, backs, 1,
+#ifdef USE_BACKREF_WITH_LEVEL
+                                                 exist_level, level,
+#endif
+                                                 env);
+          }
+
+          if (is_enclosed != 0) {
+            if (PEND) goto err_if_else;
+            PFETCH(c);
+            if (c != ')') goto err_if_else;
+          }
+        }
+        else {
+        any_condition:
+          PUNFETCH;
+          condition_is_checker = 0;
+          r = fetch_token(tok, &p, end, env);
+          if (r < 0) return r;
+          r = parse_subexp(&condition, tok, term, &p, end, env);
+          if (r < 0) {
+            onig_node_free(condition);
+            return r;
+          }
+        }
+
+        CHECK_NULL_RETURN_MEMERR(condition);
+
+        if (PEND) {
+        err_if_else:
+          onig_node_free(condition);
+          return ONIGERR_END_PATTERN_IN_GROUP;
+        }
+
+        if (PPEEK_IS(')')) { /* case: empty body: make backref checker */
+          if (condition_is_checker == 0) {
+            onig_node_free(condition);
+            return ONIGERR_INVALID_IF_ELSE_SYNTAX;
+          }
+          PFETCH(c);
+          *np = condition;
+        }
+        else { /* if-else */
+          int then_is_empty;
+          Node *Then, *Else;
+
+          if (PPEEK_IS('|')) {
+            PFETCH(c);
+            Then = 0;
+            then_is_empty = 1;
+          }
+          else
+            then_is_empty = 0;
+
+          r = fetch_token(tok, &p, end, env);
+          if (r < 0) {
+            onig_node_free(condition);
+            return r;
+          }
+          r = parse_subexp(&target, tok, term, &p, end, env);
+          if (r < 0) {
+            onig_node_free(condition);
+            onig_node_free(target);
+            return r;
+          }
+
+          if (then_is_empty != 0) {
+            Else = target;
+          }
+          else {
+            if (NODE_TYPE(target) == NODE_ALT) {
+              Then = NODE_CAR(target);
+              if (NODE_CDR(NODE_CDR(target)) == NULL_NODE) {
+                Else = NODE_CAR(NODE_CDR(target));
+                cons_node_free_alone(NODE_CDR(target));
+              }
+              else {
+                Else = NODE_CDR(target);
+              }
+              cons_node_free_alone(target);
+            }
+            else {
+              Then = target;
+              Else = 0;
+            }
+          }
+
+          *np = node_new_enclosure_if_else(condition, Then, Else);
+          if (IS_NULL(*np)) {
+            onig_node_free(condition);
+            onig_node_free(Then);
+            onig_node_free(Else);
+            return ONIGERR_MEMORY;
+          }
+        }
+        goto end;
+      }
+      else {
+        return ONIGERR_UNDEFINED_GROUP_OPTION;
+      }
+      break;
+
     case '@':
       if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_ATMARK_CAPTURE_HISTORY)) {
 #ifdef USE_NAMED_GROUP
@@ -4741,7 +5657,7 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
           PUNFETCH;
         }
 #endif
-        *np = node_new_enclosure_memory(0);
+        *np = node_new_memory(0);
         CHECK_NULL_RETURN_MEMERR(*np);
         num = scan_env_add_mem_entry(env);
         if (num < 0) {
@@ -4772,11 +5688,11 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
             break;
 
           case '-':  neg = 1; break;
-          case 'x':  ONOFF(option, ONIG_OPTION_EXTEND,     neg); break;
-          case 'i':  ONOFF(option, ONIG_OPTION_IGNORECASE, neg); break;
+          case 'x':  OPTION_NEGATE(option, ONIG_OPTION_EXTEND,     neg); break;
+          case 'i':  OPTION_NEGATE(option, ONIG_OPTION_IGNORECASE, neg); break;
           case 's':
             if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_OPTION_PERL)) {
-              ONOFF(option, ONIG_OPTION_MULTILINE,  neg);
+              OPTION_NEGATE(option, ONIG_OPTION_MULTILINE,  neg);
             }
             else
               return ONIGERR_UNDEFINED_GROUP_OPTION;
@@ -4784,17 +5700,17 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
 
           case 'm':
             if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_OPTION_PERL)) {
-              ONOFF(option, ONIG_OPTION_SINGLELINE, (neg == 0 ? 1 : 0));
+              OPTION_NEGATE(option, ONIG_OPTION_SINGLELINE, (neg == 0 ? 1 : 0));
             }
             else if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_OPTION_RUBY)) {
-              ONOFF(option, ONIG_OPTION_MULTILINE,  neg);
+              OPTION_NEGATE(option, ONIG_OPTION_MULTILINE,  neg);
             }
             else
               return ONIGERR_UNDEFINED_GROUP_OPTION;
             break;
 #ifdef USE_POSIXLINE_OPTION
           case 'p':
-            ONOFF(option, ONIG_OPTION_MULTILINE|ONIG_OPTION_SINGLELINE, neg);
+            OPTION_NEGATE(option, ONIG_OPTION_MULTILINE|ONIG_OPTION_SINGLELINE, neg);
             break;
 #endif
           default:
@@ -4808,13 +5724,13 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
             return 2; /* option only */
           }
           else if (c == ':') {
-            OnigOptionType prev = env->option;
+            OnigOptionType prev = env->options;
 
-            env->option     = option;
+            env->options = option;
             r = fetch_token(tok, &p, end, env);
             if (r < 0) return r;
             r = parse_subexp(&target, tok, term, &p, end, env);
-            env->option = prev;
+            env->options = prev;
             if (r < 0) {
               onig_node_free(target);
               return r;
@@ -4837,10 +5753,10 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
     }
   }
   else {
-    if (ONIG_IS_OPTION_ON(env->option, ONIG_OPTION_DONT_CAPTURE_GROUP))
+    if (ONIG_IS_OPTION_ON(env->options, ONIG_OPTION_DONT_CAPTURE_GROUP))
       goto group;
 
-    *np = node_new_enclosure_memory(0);
+    *np = node_new_memory(0);
     CHECK_NULL_RETURN_MEMERR(*np);
     num = scan_env_add_mem_entry(env);
     if (num < 0) return num;
@@ -4866,6 +5782,7 @@ parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
     }
   }
 
+ end:
   *src = p;
   return 0;
 }
@@ -4888,7 +5805,7 @@ set_quantifier(Node* qnode, Node* target, int group, ScanEnv* env)
     return 1;
 
   switch (NODE_TYPE(target)) {
-  case NODE_STR:
+  case NODE_STRING:
     if (! group) {
       StrNode* sn = STR_(target);
       if (str_node_can_be_split(sn, env->enc)) {
@@ -5060,7 +5977,7 @@ i_apply_case_fold(OnigCodePoint from, OnigCodePoint to[],
 
           /* char-class expanded multi-char only
              compare with string folded at match time. */
-          NSTRING_SET_AMBIG(snode);
+          NODE_STRING_SET_AMBIG(snode);
         }
         else {
           r = onig_node_str_cat(snode, buf, buf + len);
@@ -5106,13 +6023,13 @@ parse_exp(Node** np, OnigToken* tok, int term,
     if (r == 1) group = 1;
     else if (r == 2) { /* option only */
       Node* target;
-      OnigOptionType prev = env->option;
+      OnigOptionType prev = env->options;
 
-      env->option = ENCLOSURE_(*np)->o.option;
+      env->options = ENCLOSURE_(*np)->o.options;
       r = fetch_token(tok, src, end, env);
       if (r < 0) return r;
       r = parse_subexp(&target, tok, term, src, end, env);
-      env->option = prev;
+      env->options = prev;
       if (r < 0) {
         onig_node_free(target);
         return r;
@@ -5161,7 +6078,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
         if (len >= ONIGENC_MBC_MINLEN(env->enc)) {
           if (len == enclen(env->enc, STR_(*np)->s)) {//should not enclen_end()
             r = fetch_token(tok, src, end, env);
-            NSTRING_CLEAR_RAW(*np);
+            NODE_STRING_CLEAR_RAW(*np);
             goto string_end;
           }
         }
@@ -5176,7 +6093,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
             rem = ONIGENC_MBC_MINLEN(env->enc) - len;
             (void )node_str_head_pad(STR_(*np), rem, (UChar )0);
             if (len + rem == enclen(env->enc, STR_(*np)->s)) {
-              NSTRING_CLEAR_RAW(*np);
+              NODE_STRING_CLEAR_RAW(*np);
               goto string_end;
             }
           }
@@ -5266,7 +6183,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
       if (r != 0) return r;
 
       cc = CCLASS_(*np);
-      if (IS_IGNORECASE(env->option)) {
+      if (IS_IGNORECASE(env->options)) {
         IApplyCaseFoldArg iarg;
 
         iarg.env      = env;
@@ -5293,12 +6210,12 @@ parse_exp(Node** np, OnigToken* tok, int term,
     break;
 
   case TK_ANYCHAR:
-    *np = node_new_ctype(CTYPE_ANYCHAR, 0);
+    *np = node_new_anychar();
     CHECK_NULL_RETURN_MEMERR(*np);
     break;
 
   case TK_ANYCHAR_ANYTIME:
-    *np = node_new_ctype(CTYPE_ANYCHAR, 0);
+    *np = node_new_anychar();
     CHECK_NULL_RETURN_MEMERR(*np);
     qn = node_new_quantifier(0, REPEAT_INFINITE, 0);
     CHECK_NULL_RETURN_MEMERR(qn);
@@ -5319,7 +6236,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
     CHECK_NULL_RETURN_MEMERR(*np);
     break;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   case TK_CALL:
     {
       int gnum = tok->u.call.gnum;
@@ -5352,6 +6269,26 @@ parse_exp(Node** np, OnigToken* tok, int term,
     }
     break;
 
+  case TK_KEEP:
+    r = node_new_keep(np, env);
+    if (r < 0) return r;
+    break;
+
+  case TK_GENERAL_NEWLINE:
+    r = node_new_general_newline(np, env);
+    if (r < 0) return r;
+    break;
+
+  case TK_NO_NEWLINE:
+    r = node_new_no_newline(np, env);
+    if (r < 0) return r;
+    break;
+
+  case TK_TRUE_ANYCHAR:
+    r = node_new_true_anychar(np, env);
+    if (r < 0) return r;
+    break;
+
   default:
     return ONIGERR_PARSER_BUG;
     break;
@@ -5526,13 +6463,13 @@ parse_regexp(Node** top, UChar** src, UChar* end, ScanEnv* env)
   return 0;
 }
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 static int
 make_call_zero_body(Node* node, ScanEnv* env, Node** rnode)
 {
   int r;
 
-  Node* x = node_new_enclosure_memory(0 /* 0: is not named */);
+  Node* x = node_new_memory(0 /* 0: is not named */);
   CHECK_NULL_RETURN_MEMERR(x);
 
   NODE_BODY(x) = node;
@@ -5560,7 +6497,7 @@ onig_parse_tree(Node** root, const UChar* pattern, const UChar* end,
 #endif
 
   scan_env_clear(env);
-  env->option         = reg->options;
+  env->options        = reg->options;
   env->case_fold_flag = reg->case_fold_flag;
   env->enc            = reg->enc;
   env->syntax         = reg->syntax;
@@ -5576,7 +6513,7 @@ onig_parse_tree(Node** root, const UChar* pattern, const UChar* end,
   p = (UChar* )pattern;
   r = parse_regexp(root, &p, (UChar* )end, env);
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   if (r != 0) return r;
 
   if (env->has_call_zero != 0) {
diff --git a/src/regparse.h b/src/regparse.h
index 884f4d5..b7260ea 100644
--- a/src/regparse.h
+++ b/src/regparse.h
@@ -33,48 +33,58 @@
 
 /* node type */
 typedef enum {
-  NODE_STR       = 0,
-  NODE_CCLASS    = 1,
-  NODE_CTYPE     = 2,
-  NODE_BREF      = 3,
-  NODE_QUANT      = 4,
-  NODE_ENCLOSURE = 5,
-  NODE_ANCHOR    = 6,
-  NODE_LIST      = 7,
-  NODE_ALT       = 8,
-  NODE_CALL      = 9
+  NODE_STRING    =  0,
+  NODE_CCLASS    =  1,
+  NODE_CTYPE     =  2,
+  NODE_BACKREF   =  3,
+  NODE_QUANT     =  4,
+  NODE_ENCLOSURE =  5,
+  NODE_ANCHOR    =  6,
+  NODE_LIST      =  7,
+  NODE_ALT       =  8,
+  NODE_CALL      =  9,
+  NODE_GIMMICK   = 10
 } NodeType;
 
+enum GimmickType {
+  GIMMICK_FAIL = 0,
+  GIMMICK_KEEP = 1,
+  GIMMICK_SAVE = 2,
+  GIMMICK_UPDATE_VAR = 3,
+};
+
 /* node type bit */
 #define NODE_TYPE2BIT(type)      (1<<(type))
 
-#define BIT_NODE_STR        NODE_TYPE2BIT(NODE_STR)
+#define BIT_NODE_STRING     NODE_TYPE2BIT(NODE_STRING)
 #define BIT_NODE_CCLASS     NODE_TYPE2BIT(NODE_CCLASS)
 #define BIT_NODE_CTYPE      NODE_TYPE2BIT(NODE_CTYPE)
-#define BIT_NODE_BREF       NODE_TYPE2BIT(NODE_BREF)
-#define BIT_NODE_QUANT       NODE_TYPE2BIT(NODE_QUANT)
+#define BIT_NODE_BACKREF    NODE_TYPE2BIT(NODE_BACKREF)
+#define BIT_NODE_QUANT      NODE_TYPE2BIT(NODE_QUANT)
 #define BIT_NODE_ENCLOSURE  NODE_TYPE2BIT(NODE_ENCLOSURE)
 #define BIT_NODE_ANCHOR     NODE_TYPE2BIT(NODE_ANCHOR)
 #define BIT_NODE_LIST       NODE_TYPE2BIT(NODE_LIST)
 #define BIT_NODE_ALT        NODE_TYPE2BIT(NODE_ALT)
 #define BIT_NODE_CALL       NODE_TYPE2BIT(NODE_CALL)
+#define BIT_NODE_GIMMICK    NODE_TYPE2BIT(NODE_GIMMICK)
 
 #define NODE_IS_SIMPLE_TYPE(node) \
   ((NODE_TYPE2BIT(NODE_TYPE(node)) & \
-    (BIT_NODE_STR | BIT_NODE_CCLASS | BIT_NODE_CTYPE | BIT_NODE_BREF)) != 0)
+    (BIT_NODE_STRING | BIT_NODE_CCLASS | BIT_NODE_CTYPE | BIT_NODE_BACKREF)) != 0)
 
 #define NODE_TYPE(node)             ((node)->u.base.node_type)
-#define SET_NODE_TYPE(node, ntype)   (node)->u.base.node_type = (ntype)
+#define NODE_SET_TYPE(node, ntype)   (node)->u.base.node_type = (ntype)
 
 #define STR_(node)         (&((node)->u.str))
 #define CCLASS_(node)      (&((node)->u.cclass))
 #define CTYPE_(node)       (&((node)->u.ctype))
-#define BREF_(node)        (&((node)->u.bref))
-#define QUANT_(node)        (&((node)->u.quant))
-#define ENCLOSURE_(node)     (&((node)->u.enclosure))
+#define BACKREF_(node)     (&((node)->u.backref))
+#define QUANT_(node)       (&((node)->u.quant))
+#define ENCLOSURE_(node)   (&((node)->u.enclosure))
 #define ANCHOR_(node)      (&((node)->u.anchor))
 #define CONS_(node)        (&((node)->u.cons))
 #define CALL_(node)        (&((node)->u.call))
+#define GIMMICK_(node)     (&((node)->u.gimmick))
 
 #define NODE_CAR(node)         (CONS_(node)->car)
 #define NODE_CDR(node)         (CONS_(node)->cdr)
@@ -83,6 +93,9 @@ typedef enum {
 #define NODE_IS_ANYCHAR(node) \
   (NODE_TYPE(node) == NODE_CTYPE && CTYPE_(node)->ctype == CTYPE_ANYCHAR)
 
+#define CTYPE_OPTION(node, reg) \
+  (NODE_IS_FIXED_OPTION(node) ? CTYPE_(node)->options : reg->options)
+
 
 #define ANCHOR_ANYCHAR_STAR_MASK (ANCHOR_ANYCHAR_STAR | ANCHOR_ANYCHAR_STAR_ML)
 #define ANCHOR_END_BUF_MASK      (ANCHOR_END_BUF | ANCHOR_SEMI_END_BUF)
@@ -90,24 +103,25 @@ typedef enum {
 #define ENCLOSURE_MEMORY           (1<<0)
 #define ENCLOSURE_OPTION           (1<<1)
 #define ENCLOSURE_STOP_BACKTRACK   (1<<2)
+#define ENCLOSURE_IF_ELSE          (1<<3)
 
-#define NODE_STR_MARGIN         16
-#define NODE_STR_BUF_SIZE       24  /* sizeof(CClassNode) - sizeof(int)*4 */
+#define NODE_STRING_MARGIN         16
+#define NODE_STRING_BUF_SIZE       24  /* sizeof(CClassNode) - sizeof(int)*4 */
 #define NODE_BACKREFS_SIZE       6
 
 #define STRING_RAW                (1<<0) /* by backslashed number */
 #define STRING_AMBIG              (1<<1)
 #define STRING_DONT_GET_OPT_INFO  (1<<2)
 
-#define NSTRING_LEN(node)             ((node)->u.str.end - (node)->u.str.s)
-#define NSTRING_SET_RAW(node)          (node)->u.str.flag |= STRING_RAW
-#define NSTRING_CLEAR_RAW(node)        (node)->u.str.flag &= ~STRING_RAW
-#define NSTRING_SET_AMBIG(node)        (node)->u.str.flag |= STRING_AMBIG
-#define NSTRING_SET_DONT_GET_OPT_INFO(node) \
+#define NODE_STRING_LEN(node)             ((node)->u.str.end - (node)->u.str.s)
+#define NODE_STRING_SET_RAW(node)          (node)->u.str.flag |= STRING_RAW
+#define NODE_STRING_CLEAR_RAW(node)        (node)->u.str.flag &= ~STRING_RAW
+#define NODE_STRING_SET_AMBIG(node)        (node)->u.str.flag |= STRING_AMBIG
+#define NODE_STRING_SET_DONT_GET_OPT_INFO(node) \
   (node)->u.str.flag |= STRING_DONT_GET_OPT_INFO
-#define NSTRING_IS_RAW(node)          (((node)->u.str.flag & STRING_RAW)   != 0)
-#define NSTRING_IS_AMBIG(node)        (((node)->u.str.flag & STRING_AMBIG) != 0)
-#define NSTRING_IS_DONT_GET_OPT_INFO(node) \
+#define NODE_STRING_IS_RAW(node)          (((node)->u.str.flag & STRING_RAW)   != 0)
+#define NODE_STRING_IS_AMBIG(node)        (((node)->u.str.flag & STRING_AMBIG) != 0)
+#define NODE_STRING_IS_DONT_GET_OPT_INFO(node) \
   (((node)->u.str.flag & STRING_DONT_GET_OPT_INFO) != 0)
 
 #define BACKREFS_P(br) \
@@ -118,7 +132,7 @@ typedef enum {
 #define QUANT_BODY_IS_EMPTY_MEM    2
 #define QUANT_BODY_IS_EMPTY_REC    3
 
-/* status bits */
+/* node status bits */
 #define NST_MIN_FIXED             (1<<0)
 #define NST_MAX_FIXED             (1<<1)
 #define NST_CLEN_FIXED            (1<<2)
@@ -136,28 +150,37 @@ typedef enum {
 #define NST_BY_NUMBER             (1<<14) /* {n,m} */
 #define NST_BY_NAME               (1<<15) /* backref by name */
 #define NST_BACKREF               (1<<16)
+#define NST_CHECKER               (1<<17)
+#define NST_FIXED_OPTION          (1<<18)
+#define NST_PROHIBIT_RECURSION    (1<<19)
+#define NST_SUPER                 (1<<20)
 
 
 #define NODE_STATUS(node)           (((Node* )node)->u.base.status)
 #define NODE_STATUS_ADD(node,f)     (NODE_STATUS(node) |= (f))
 #define NODE_STATUS_REMOVE(node,f)  (NODE_STATUS(node) &= ~(f))
 
-#define NODE_IS_BY_NUMBER(node)       ((NODE_STATUS(node) & NST_BY_NUMBER) != 0)
+#define NODE_IS_BY_NUMBER(node)       ((NODE_STATUS(node) & NST_BY_NUMBER)      != 0)
 #define NODE_IS_IN_REAL_REPEAT(node)  ((NODE_STATUS(node) & NST_IN_REAL_REPEAT) != 0)
-#define NODE_IS_CALLED(node)          ((NODE_STATUS(node) & NST_CALLED)    != 0)
+#define NODE_IS_CALLED(node)          ((NODE_STATUS(node) & NST_CALLED)         != 0)
 #define NODE_IS_IN_MULTI_ENTRY(node)  ((NODE_STATUS(node) & NST_IN_MULTI_ENTRY) != 0)
-#define NODE_IS_RECURSION(node)       ((NODE_STATUS(node) & NST_RECURSION) != 0)
+#define NODE_IS_RECURSION(node)       ((NODE_STATUS(node) & NST_RECURSION)      != 0)
 #define NODE_IS_IN_ZERO_REPEAT(node)  ((NODE_STATUS(node) & NST_IN_ZERO_REPEAT) != 0)
-#define NODE_IS_NAMED_GROUP(node)     ((NODE_STATUS(node) & NST_NAMED_GROUP) != 0)
-#define NODE_IS_ADDR_FIXED(node)      ((NODE_STATUS(node) & NST_ADDR_FIXED)  != 0)
-#define NODE_IS_CLEN_FIXED(node)      ((NODE_STATUS(node) & NST_CLEN_FIXED)  != 0)
-#define NODE_IS_MIN_FIXED(node)       ((NODE_STATUS(node) & NST_MIN_FIXED)   != 0)
-#define NODE_IS_MAX_FIXED(node)       ((NODE_STATUS(node) & NST_MAX_FIXED)   != 0)
-#define NODE_IS_MARK1(node)           ((NODE_STATUS(node) & NST_MARK1)       != 0)
-#define NODE_IS_MARK2(node)           ((NODE_STATUS(node) & NST_MARK2)       != 0)
-#define NODE_IS_NEST_LEVEL(node)      ((NODE_STATUS(node) & NST_NEST_LEVEL)  != 0)
-#define NODE_IS_BY_NAME(node)         ((NODE_STATUS(node) & NST_BY_NAME)     != 0)
-#define NODE_IS_BACKREF(node)         ((NODE_STATUS(node) & NST_BACKREF)     != 0)
+#define NODE_IS_NAMED_GROUP(node)     ((NODE_STATUS(node) & NST_NAMED_GROUP)  != 0)
+#define NODE_IS_ADDR_FIXED(node)      ((NODE_STATUS(node) & NST_ADDR_FIXED)   != 0)
+#define NODE_IS_CLEN_FIXED(node)      ((NODE_STATUS(node) & NST_CLEN_FIXED)   != 0)
+#define NODE_IS_MIN_FIXED(node)       ((NODE_STATUS(node) & NST_MIN_FIXED)    != 0)
+#define NODE_IS_MAX_FIXED(node)       ((NODE_STATUS(node) & NST_MAX_FIXED)    != 0)
+#define NODE_IS_MARK1(node)           ((NODE_STATUS(node) & NST_MARK1)        != 0)
+#define NODE_IS_MARK2(node)           ((NODE_STATUS(node) & NST_MARK2)        != 0)
+#define NODE_IS_NEST_LEVEL(node)      ((NODE_STATUS(node) & NST_NEST_LEVEL)   != 0)
+#define NODE_IS_BY_NAME(node)         ((NODE_STATUS(node) & NST_BY_NAME)      != 0)
+#define NODE_IS_BACKREF(node)         ((NODE_STATUS(node) & NST_BACKREF)      != 0)
+#define NODE_IS_CHECKER(node)         ((NODE_STATUS(node) & NST_CHECKER)      != 0)
+#define NODE_IS_FIXED_OPTION(node)    ((NODE_STATUS(node) & NST_FIXED_OPTION) != 0)
+#define NODE_IS_SUPER(node)           ((NODE_STATUS(node) & NST_SUPER)        != 0)
+#define NODE_IS_PROHIBIT_RECURSION(node) \
+    ((NODE_STATUS(node) & NST_PROHIBIT_RECURSION) != 0)
 #define NODE_IS_STOP_BT_SIMPLE_REPEAT(node) \
     ((NODE_STATUS(node) & NST_STOP_BT_SIMPLE_REPEAT) != 0)
 
@@ -168,8 +191,6 @@ typedef enum {
 #define NODE_ANCHOR_BODY(node)    ((node)->body)
 
 
-#define CALLNODE_REFNUM_UNDEF  -1
-
 typedef struct {
   NodeType node_type;
   int status;
@@ -178,7 +199,7 @@ typedef struct {
   UChar* end;
   unsigned int flag;
   int    capa;    /* (allocated size - 1) or 0: use buf[] */
-  UChar  buf[NODE_STR_BUF_SIZE];
+  UChar  buf[NODE_STRING_BUF_SIZE];
 } StrNode;
 
 typedef struct {
@@ -221,17 +242,22 @@ typedef struct {
       int called_state;
     } m;
     struct {
-      OnigOptionType option;
+      OnigOptionType options;
     } o;
+    struct {
+      /* body is condition */
+      struct _Node* Then;
+      struct _Node* Else;
+    } te;
   };
   /* for multiple call reference */
-  OnigLen min_len; /* min length (byte) */
-  OnigLen max_len; /* max length (byte) */
-  int char_len;         /* character length  */
-  int opt_count;        /* referenced count in optimize_node_left() */
+  OnigLen min_len;   /* min length (byte) */
+  OnigLen max_len;   /* max length (byte) */
+  int char_len;      /* character length  */
+  int opt_count;     /* referenced count in optimize_node_left() */
 } EnclosureNode;
 
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
 
 typedef struct {
   int           offset;
@@ -266,7 +292,7 @@ typedef struct {
   int  back_static[NODE_BACKREFS_SIZE];
   int* back_dynamic;
   int  nest_level;
-} BRefNode;
+} BackRefNode;
 
 typedef struct {
   NodeType node_type;
@@ -291,8 +317,18 @@ typedef struct {
 
   int ctype;
   int not;
+  OnigOptionType options;
 } CtypeNode;
 
+typedef struct {
+  NodeType node_type;
+  int status;
+
+  enum GimmickType type;
+  int  detail_type;
+  int  id;
+} GimmickNode;
+
 typedef struct _Node {
   union {
     struct {
@@ -305,13 +341,14 @@ typedef struct _Node {
     CClassNode    cclass;
     QuantNode     quant;
     EnclosureNode enclosure;
-    BRefNode      bref;
+    BackRefNode   backref;
     AnchorNode    anchor;
     ConsAltNode   cons;
     CtypeNode     ctype;
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
     CallNode      call;
 #endif
+    GimmickNode   gimmick;
   } u;
 } Node;
 
@@ -332,7 +369,11 @@ typedef struct {
 } MemEnv;
 
 typedef struct {
-  OnigOptionType   option;
+  enum SaveType type;
+} SaveItem;
+
+typedef struct {
+  OnigOptionType   options;
   OnigCaseFoldType case_fold_flag;
   OnigEncoding     enc;
   OnigSyntaxType*  syntax;
@@ -346,7 +387,7 @@ typedef struct {
   UChar*           error_end;
   regex_t*         reg;       /* for reg->names only */
   int              num_call;
-#ifdef USE_SUBEXP_CALL
+#ifdef USE_CALL
   UnsetAddrList*   unset_addr_list;
   int              has_call_zero;
 #endif
@@ -364,6 +405,11 @@ typedef struct {
   int has_recursion;
 #endif
   unsigned int parse_depth;
+
+  int keep_num;
+  int save_num;
+  int save_alloc_num;
+  SaveItem* saves;
 } ScanEnv;
 
 
@@ -399,6 +445,7 @@ extern int    onig_names_free P_((regex_t* reg));
 extern int    onig_parse_tree P_((Node** root, const UChar* pattern, const UChar* end, regex_t* reg, ScanEnv* env));
 extern int    onig_free_shared_cclass_table P_((void));
 extern int    onig_is_code_in_cc P_((OnigEncoding enc, OnigCodePoint code, CClassNode* cc));
+extern OnigLen onig_get_tiny_min_len(Node* node, unsigned int inhibit_node_types, int* invalid_node);
 
 #ifdef ONIG_DEBUG
 #ifdef USE_NAMED_GROUP
diff --git a/src/regposix.c b/src/regposix.c
index bbe52dc..32b11b5 100644
--- a/src/regposix.c
+++ b/src/regposix.c
@@ -2,7 +2,7 @@
   regposix.c - Oniguruma (regular expression library)
 **********************************************************************/
 /*-
- * Copyright (c) 2002-2008  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+ * Copyright (c) 2002-2017  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -114,6 +114,9 @@ onig2posix_error_code(int code)
     { ONIGERR_NEVER_ENDING_RECURSION,                     REG_BADPAT },
     { ONIGERR_GROUP_NUMBER_OVER_FOR_CAPTURE_HISTORY,      REG_BADPAT },
     { ONIGERR_INVALID_CHAR_PROPERTY_NAME,                 REG_BADPAT },
+    { ONIGERR_INVALID_IF_ELSE_SYNTAX,                     REG_BADPAT },
+    { ONIGERR_INVALID_ABSENT_GROUP_PATTERN,               REG_BADPAT },
+    { ONIGERR_INVALID_ABSENT_GROUP_GENERATOR_PATTERN,     REG_BADPAT },
     { ONIGERR_NOT_SUPPORTED_ENCODING_COMBINATION,         REG_EONIG_BADARG },
     { ONIGERR_LIBRARY_IS_NOT_INITIALIZED,                 REG_EONIG_INTERNAL }
   };
diff --git a/src/regsyntax.c b/src/regsyntax.c
index e751e24..6833e1d 100644
--- a/src/regsyntax.c
+++ b/src/regsyntax.c
@@ -2,7 +2,7 @@
   regsyntax.c -  Oniguruma (regular expression library)
 **********************************************************************/
 /*-
- * Copyright (c) 2002-2006  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+ * Copyright (c) 2002-2017  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -174,8 +174,13 @@ OnigSyntaxType OnigSyntaxPerl = {
    & ~ONIG_SYN_OP_ESC_LTGT_WORD_BEGIN_END )
   , ( ONIG_SYN_OP2_ESC_CAPITAL_Q_QUOTE |
       ONIG_SYN_OP2_QMARK_GROUP_EFFECT | ONIG_SYN_OP2_OPTION_PERL |
+      ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE |
+      ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP |
       ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY |
-      ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT )
+      ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT |
+      ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP |
+      ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE |
+      ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT )
   , SYN_GNU_REGEX_BV
   , ONIG_OPTION_SINGLELINE
   ,
@@ -199,11 +204,16 @@ OnigSyntaxType OnigSyntaxPerl_NG = {
    & ~ONIG_SYN_OP_ESC_LTGT_WORD_BEGIN_END )
   , ( ONIG_SYN_OP2_ESC_CAPITAL_Q_QUOTE |
       ONIG_SYN_OP2_QMARK_GROUP_EFFECT | ONIG_SYN_OP2_OPTION_PERL |
+      ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE |
+      ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP |
       ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY  |
       ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT |
       ONIG_SYN_OP2_QMARK_LT_NAMED_GROUP       |
       ONIG_SYN_OP2_ESC_K_NAMED_BACKREF        |
-      ONIG_SYN_OP2_ESC_G_SUBEXP_CALL )
+      ONIG_SYN_OP2_ESC_G_SUBEXP_CALL |
+      ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP |
+      ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE |
+      ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT )
   , ( SYN_GNU_REGEX_BV |
       ONIG_SYN_CAPTURE_ONLY_NAMED_GROUP |
       ONIG_SYN_ALLOW_MULTIPLEX_DEFINITION_NAME )
diff --git a/src/utf8.c b/src/utf8.c
index 219b7ea..1ad9653 100644
--- a/src/utf8.c
+++ b/src/utf8.c
@@ -90,6 +90,7 @@ is_valid_mbc_string(const UChar* p, const UChar* end)
   return TRUE;
 }
 
+#if 0
 static int
 is_mbc_newline(const UChar* p, const UChar* end)
 {
@@ -114,6 +115,7 @@ is_mbc_newline(const UChar* p, const UChar* end)
 
   return 0;
 }
+#endif
 
 static OnigCodePoint
 mbc_to_code(const UChar* p, const UChar* end)
@@ -246,43 +248,6 @@ mbc_case_fold(OnigCaseFoldType flag, const UChar** pp,
   }
 }
 
-#if 0
-static int
-is_mbc_ambiguous(OnigCaseFoldType flag, const UChar** pp, const UChar* end)
-{
-  const UChar* p = *pp;
-
-  if (ONIGENC_IS_MBC_ASCII(p)) {
-    (*pp)++;
-    return ONIGENC_IS_ASCII_CODE_CASE_AMBIG(*p);
-  }
-  else {
-    (*pp) += enclen(ONIG_ENCODING_UTF8, p);
-
-    if (*p == 0xc3) {
-      int c = *(p + 1);
-      if (c >= 0x80) {
-        if (c <= (UChar )0x9e) { /* upper */
-          if (c == (UChar )0x97) return FALSE;
-          return TRUE;
-        }
-        else if (c >= (UChar )0xa0 && c <= (UChar )0xbe) { /* lower */
-          if (c == (UChar )'\267') return FALSE;
-          return TRUE;
-        }
-        else if (c == (UChar )0x9f &&
-                 (flag & INTERNAL_ONIGENC_CASE_FOLD_MULTI_CHAR) != 0) {
-          return TRUE;
-        }
-      }
-    }
-  }
-
-  return FALSE;
-}
-#endif
-
-
 static int
 get_ctype_code_range(OnigCtype ctype, OnigCodePoint *sb_out,
 		     const OnigCodePoint* ranges[])
@@ -317,7 +282,7 @@ OnigEncodingType OnigEncodingUTF8 = {
   "UTF-8",     /* name */
   6,           /* max byte length */
   1,           /* min byte length */
-  is_mbc_newline,
+  onigenc_is_mbc_newline_0x0a,
   mbc_to_code,
   code_to_mbclen,
   code_to_mbc,