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Diffstat (limited to 'engine/SCons/compat/_scons_textwrap.py')
| -rw-r--r-- | engine/SCons/compat/_scons_textwrap.py | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/engine/SCons/compat/_scons_textwrap.py b/engine/SCons/compat/_scons_textwrap.py new file mode 100644 index 0000000..81781af --- /dev/null +++ b/engine/SCons/compat/_scons_textwrap.py @@ -0,0 +1,382 @@ +"""Text wrapping and filling. +""" + +# Copyright (C) 1999-2001 Gregory P. Ward. +# Copyright (C) 2002, 2003 Python Software Foundation. +# Written by Greg Ward <gward@python.net> + +__revision__ = "$Id: textwrap.py,v 1.32.8.2 2004/05/13 01:48:15 gward Exp $" + +import string, re + +try: + unicode +except NameError: + class unicode: + pass + +# Do the right thing with boolean values for all known Python versions +# (so this module can be copied to projects that don't depend on Python +# 2.3, e.g. Optik and Docutils). +try: + True, False +except NameError: + (True, False) = (1, 0) + +__all__ = ['TextWrapper', 'wrap', 'fill'] + +# Hardcode the recognized whitespace characters to the US-ASCII +# whitespace characters. The main reason for doing this is that in +# ISO-8859-1, 0xa0 is non-breaking whitespace, so in certain locales +# that character winds up in string.whitespace. Respecting +# string.whitespace in those cases would 1) make textwrap treat 0xa0 the +# same as any other whitespace char, which is clearly wrong (it's a +# *non-breaking* space), 2) possibly cause problems with Unicode, +# since 0xa0 is not in range(128). +_whitespace = '\t\n\x0b\x0c\r ' + +class TextWrapper: + """ + Object for wrapping/filling text. The public interface consists of + the wrap() and fill() methods; the other methods are just there for + subclasses to override in order to tweak the default behaviour. + If you want to completely replace the main wrapping algorithm, + you'll probably have to override _wrap_chunks(). + + Several instance attributes control various aspects of wrapping: + width (default: 70) + the maximum width of wrapped lines (unless break_long_words + is false) + initial_indent (default: "") + string that will be prepended to the first line of wrapped + output. Counts towards the line's width. + subsequent_indent (default: "") + string that will be prepended to all lines save the first + of wrapped output; also counts towards each line's width. + expand_tabs (default: true) + Expand tabs in input text to spaces before further processing. + Each tab will become 1 .. 8 spaces, depending on its position in + its line. If false, each tab is treated as a single character. + replace_whitespace (default: true) + Replace all whitespace characters in the input text by spaces + after tab expansion. Note that if expand_tabs is false and + replace_whitespace is true, every tab will be converted to a + single space! + fix_sentence_endings (default: false) + Ensure that sentence-ending punctuation is always followed + by two spaces. Off by default because the algorithm is + (unavoidably) imperfect. + break_long_words (default: true) + Break words longer than 'width'. If false, those words will not + be broken, and some lines might be longer than 'width'. + """ + + whitespace_trans = string.maketrans(_whitespace, ' ' * len(_whitespace)) + + unicode_whitespace_trans = {} + try: + uspace = eval("ord(u' ')") + except SyntaxError: + # Python1.5 doesn't understand u'' syntax, in which case we + # won't actually use the unicode translation below, so it + # doesn't matter what value we put in the table. + uspace = ord(' ') + for x in map(ord, _whitespace): + unicode_whitespace_trans[x] = uspace + + # This funky little regex is just the trick for splitting + # text up into word-wrappable chunks. E.g. + # "Hello there -- you goof-ball, use the -b option!" + # splits into + # Hello/ /there/ /--/ /you/ /goof-/ball,/ /use/ /the/ /-b/ /option! + # (after stripping out empty strings). + try: + wordsep_re = re.compile(r'(\s+|' # any whitespace + r'[^\s\w]*\w{2,}-(?=\w{2,})|' # hyphenated words + r'(?<=[\w\!\"\'\&\.\,\?])-{2,}(?=\w))') # em-dash + except re.error: + # Pre-2.0 Python versions don't have the (?<= negative look-behind + # assertion. It mostly doesn't matter for the simple input + # SCons is going to give it, so just leave it out. + wordsep_re = re.compile(r'(\s+|' # any whitespace + r'-*\w{2,}-(?=\w{2,}))') # hyphenated words + + # XXX will there be a locale-or-charset-aware version of + # string.lowercase in 2.3? + sentence_end_re = re.compile(r'[%s]' # lowercase letter + r'[\.\!\?]' # sentence-ending punct. + r'[\"\']?' # optional end-of-quote + % string.lowercase) + + + def __init__(self, + width=70, + initial_indent="", + subsequent_indent="", + expand_tabs=True, + replace_whitespace=True, + fix_sentence_endings=False, + break_long_words=True): + self.width = width + self.initial_indent = initial_indent + self.subsequent_indent = subsequent_indent + self.expand_tabs = expand_tabs + self.replace_whitespace = replace_whitespace + self.fix_sentence_endings = fix_sentence_endings + self.break_long_words = break_long_words + + + # -- Private methods ----------------------------------------------- + # (possibly useful for subclasses to override) + + def _munge_whitespace(self, text): + """_munge_whitespace(text : string) -> string + + Munge whitespace in text: expand tabs and convert all other + whitespace characters to spaces. Eg. " foo\tbar\n\nbaz" + becomes " foo bar baz". + """ + if self.expand_tabs: + text = string.expandtabs(text) + if self.replace_whitespace: + if type(text) == type(''): + text = string.translate(text, self.whitespace_trans) + elif isinstance(text, unicode): + text = string.translate(text, self.unicode_whitespace_trans) + return text + + + def _split(self, text): + """_split(text : string) -> [string] + + Split the text to wrap into indivisible chunks. Chunks are + not quite the same as words; see wrap_chunks() for full + details. As an example, the text + Look, goof-ball -- use the -b option! + breaks into the following chunks: + 'Look,', ' ', 'goof-', 'ball', ' ', '--', ' ', + 'use', ' ', 'the', ' ', '-b', ' ', 'option!' + """ + chunks = self.wordsep_re.split(text) + chunks = filter(None, chunks) + return chunks + + def _fix_sentence_endings(self, chunks): + """_fix_sentence_endings(chunks : [string]) + + Correct for sentence endings buried in 'chunks'. Eg. when the + original text contains "... foo.\nBar ...", munge_whitespace() + and split() will convert that to [..., "foo.", " ", "Bar", ...] + which has one too few spaces; this method simply changes the one + space to two. + """ + i = 0 + pat = self.sentence_end_re + while i < len(chunks)-1: + if chunks[i+1] == " " and pat.search(chunks[i]): + chunks[i+1] = " " + i = i + 2 + else: + i = i + 1 + + def _handle_long_word(self, chunks, cur_line, cur_len, width): + """_handle_long_word(chunks : [string], + cur_line : [string], + cur_len : int, width : int) + + Handle a chunk of text (most likely a word, not whitespace) that + is too long to fit in any line. + """ + space_left = max(width - cur_len, 1) + + # If we're allowed to break long words, then do so: put as much + # of the next chunk onto the current line as will fit. + if self.break_long_words: + cur_line.append(chunks[0][0:space_left]) + chunks[0] = chunks[0][space_left:] + + # Otherwise, we have to preserve the long word intact. Only add + # it to the current line if there's nothing already there -- + # that minimizes how much we violate the width constraint. + elif not cur_line: + cur_line.append(chunks.pop(0)) + + # If we're not allowed to break long words, and there's already + # text on the current line, do nothing. Next time through the + # main loop of _wrap_chunks(), we'll wind up here again, but + # cur_len will be zero, so the next line will be entirely + # devoted to the long word that we can't handle right now. + + def _wrap_chunks(self, chunks): + """_wrap_chunks(chunks : [string]) -> [string] + + Wrap a sequence of text chunks and return a list of lines of + length 'self.width' or less. (If 'break_long_words' is false, + some lines may be longer than this.) Chunks correspond roughly + to words and the whitespace between them: each chunk is + indivisible (modulo 'break_long_words'), but a line break can + come between any two chunks. Chunks should not have internal + whitespace; ie. a chunk is either all whitespace or a "word". + Whitespace chunks will be removed from the beginning and end of + lines, but apart from that whitespace is preserved. + """ + lines = [] + if self.width <= 0: + raise ValueError("invalid width %r (must be > 0)" % self.width) + + while chunks: + + # Start the list of chunks that will make up the current line. + # cur_len is just the length of all the chunks in cur_line. + cur_line = [] + cur_len = 0 + + # Figure out which static string will prefix this line. + if lines: + indent = self.subsequent_indent + else: + indent = self.initial_indent + + # Maximum width for this line. + width = self.width - len(indent) + + # First chunk on line is whitespace -- drop it, unless this + # is the very beginning of the text (ie. no lines started yet). + if string.strip(chunks[0]) == '' and lines: + del chunks[0] + + while chunks: + l = len(chunks[0]) + + # Can at least squeeze this chunk onto the current line. + if cur_len + l <= width: + cur_line.append(chunks.pop(0)) + cur_len = cur_len + l + + # Nope, this line is full. + else: + break + + # The current line is full, and the next chunk is too big to + # fit on *any* line (not just this one). + if chunks and len(chunks[0]) > width: + self._handle_long_word(chunks, cur_line, cur_len, width) + + # If the last chunk on this line is all whitespace, drop it. + if cur_line and string.strip(cur_line[-1]) == '': + del cur_line[-1] + + # Convert current line back to a string and store it in list + # of all lines (return value). + if cur_line: + lines.append(indent + string.join(cur_line, '')) + + return lines + + + # -- Public interface ---------------------------------------------- + + def wrap(self, text): + """wrap(text : string) -> [string] + + Reformat the single paragraph in 'text' so it fits in lines of + no more than 'self.width' columns, and return a list of wrapped + lines. Tabs in 'text' are expanded with string.expandtabs(), + and all other whitespace characters (including newline) are + converted to space. + """ + text = self._munge_whitespace(text) + indent = self.initial_indent + chunks = self._split(text) + if self.fix_sentence_endings: + self._fix_sentence_endings(chunks) + return self._wrap_chunks(chunks) + + def fill(self, text): + """fill(text : string) -> string + + Reformat the single paragraph in 'text' to fit in lines of no + more than 'self.width' columns, and return a new string + containing the entire wrapped paragraph. + """ + return string.join(self.wrap(text), "\n") + + +# -- Convenience interface --------------------------------------------- + +def wrap(text, width=70, **kwargs): + """Wrap a single paragraph of text, returning a list of wrapped lines. + + Reformat the single paragraph in 'text' so it fits in lines of no + more than 'width' columns, and return a list of wrapped lines. By + default, tabs in 'text' are expanded with string.expandtabs(), and + all other whitespace characters (including newline) are converted to + space. See TextWrapper class for available keyword args to customize + wrapping behaviour. + """ + kw = kwargs.copy() + kw['width'] = width + w = apply(TextWrapper, (), kw) + return w.wrap(text) + +def fill(text, width=70, **kwargs): + """Fill a single paragraph of text, returning a new string. + + Reformat the single paragraph in 'text' to fit in lines of no more + than 'width' columns, and return a new string containing the entire + wrapped paragraph. As with wrap(), tabs are expanded and other + whitespace characters converted to space. See TextWrapper class for + available keyword args to customize wrapping behaviour. + """ + kw = kwargs.copy() + kw['width'] = width + w = apply(TextWrapper, (), kw) + return w.fill(text) + + +# -- Loosely related functionality ------------------------------------- + +def dedent(text): + """dedent(text : string) -> string + + Remove any whitespace than can be uniformly removed from the left + of every line in `text`. + + This can be used e.g. to make triple-quoted strings line up with + the left edge of screen/whatever, while still presenting it in the + source code in indented form. + + For example: + + def test(): + # end first line with \ to avoid the empty line! + s = '''\ + hello + world + ''' + print repr(s) # prints ' hello\n world\n ' + print repr(dedent(s)) # prints 'hello\n world\n' + """ + lines = text.expandtabs().split('\n') + margin = None + for line in lines: + content = line.lstrip() + if not content: + continue + indent = len(line) - len(content) + if margin is None: + margin = indent + else: + margin = min(margin, indent) + + if margin is not None and margin > 0: + for i in range(len(lines)): + lines[i] = lines[i][margin:] + + return string.join(lines, '\n') + +# Local Variables: +# tab-width:4 +# indent-tabs-mode:nil +# End: +# vim: set expandtab tabstop=4 shiftwidth=4: |