path: root/src/engine/SCons/Tool/textfile.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright (c) 2001 - 2015 The SCons Foundation

This file is processed by the bin/SConsDoc.py module.
See its __doc__ string for a discussion of the format.
-->

<!DOCTYPE sconsdoc [
<!ENTITY % scons SYSTEM '../../../../doc/scons.mod'>
%scons;
<!ENTITY % builders-mod SYSTEM '../../../../doc/generated/builders.mod'>
%builders-mod;
<!ENTITY % functions-mod SYSTEM '../../../../doc/generated/functions.mod'>
%functions-mod;
<!ENTITY % tools-mod SYSTEM '../../../../doc/generated/tools.mod'>
%tools-mod;
<!ENTITY % variables-mod SYSTEM '../../../../doc/generated/variables.mod'>
%variables-mod;
]>

<sconsdoc xmlns="http://www.scons.org/dbxsd/v1.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://www.scons.org/dbxsd/v1.0 http://www.scons.org/dbxsd/v1.0/scons.xsd">

<tool name="textfile">
<summary>
<para>
Set construction variables for the &b-Textfile; and &b-Substfile; builders.
</para>
</summary>
<sets>
<item>LINESEPARATOR</item>
<item>SUBSTFILEPREFIX</item>
<item>SUBSTFILESUFFIX</item>
<item>TEXTFILEPREFIX</item>
<item>TEXTFILESUFFIX</item>
</sets>
<uses>
<item>SUBST_DICT</item>
</uses>
</tool>

<builder name="Textfile">
<summary>
<para>
The &b-Textfile; builder generates a single text file.
The source strings constitute the lines;
nested lists of sources are flattened.
&cv-LINESEPARATOR; is used to separate the strings.
</para>

<para>
If present, the &cv-SUBST_DICT; construction variable
is used to modify the strings before they are written;
see the &b-Substfile; description for details.
</para>

<para>
The prefix and suffix specified by the &cv-TEXTFILEPREFIX;
and &cv-TEXTFILESUFFIX; construction variables
(the null string and <filename>.txt</filename> by default, respectively)
are automatically added to the target if they are not already present.
Examples:
</para>

<example_commands>
# builds/writes foo.txt
env.Textfile(target = 'foo.txt', source = ['Goethe', 42, 'Schiller'])

# builds/writes bar.txt
env.Textfile(target = 'bar',
             source = ['lalala', 'tanteratei'],
             LINESEPARATOR='|*')

# nested lists are flattened automatically
env.Textfile(target = 'blob',
             source = ['lalala', ['Goethe', 42 'Schiller'], 'tanteratei'])

# files may be used as input by wraping them in File()
env.Textfile(target = 'concat',  # concatenate files with a marker between
             source = [File('concat1'), File('concat2')],
             LINESEPARATOR = '====================\n')

Results are:
foo.txt
  ....8&lt;----
  Goethe
  42
  Schiller
  ....8&lt;---- (no linefeed at the end)

bar.txt:
  ....8&lt;----
  lalala|*tanteratei
  ....8&lt;---- (no linefeed at the end)

blob.txt
  ....8&lt;----
  lalala
  Goethe
  42
  Schiller
  tanteratei
  ....8&lt;---- (no linefeed at the end)
</example_commands>
</summary>
</builder>

<builder name="Substfile">
<summary>
<para>
The &b-Substfile; builder creates a single text file from another file or set of
files by concatenating them with &cv-LINESEPARATOR; and replacing text
using the &cv-SUBST_DICT; construction variable. Nested lists of source files
are flattened. See also &b-Textfile;.
</para>

<para>
If a single source file is present with an <filename>.in</filename> suffix,
the suffix is stripped and the remainder is used as the default target name.
</para>

<para>
The prefix and suffix specified by the &cv-SUBSTFILEPREFIX;
and &cv-SUBSTFILESUFFIX; construction variables
(the null string by default in both cases)
are automatically added to the target if they are not already present.
</para>

<para>
If a construction variable named &cv-SUBST_DICT; is present,
it may be either a Python dictionary or a sequence of (key,value) tuples.
If it is a dictionary it is converted into a list of tuples in an arbitrary order,
so if one key is a prefix of another key
or if one substitution could be further expanded by another subsitition,
it is unpredictable whether the expansion will occur.
</para>

<para>
Any occurrences of a key in the source
are replaced by the corresponding value,
which may be a Python callable function or a string.
If the value is a callable, it is called with no arguments to get a string.
Strings are <emphasis>subst</emphasis>-expanded
and the result replaces the key.
</para>

<example_commands>
env = Environment(tools = ['default', 'textfile'])

env['prefix'] = '/usr/bin'
script_dict = {'@prefix@': '/bin', @exec_prefix@: '$prefix'}
env.Substfile('script.in', SUBST_DICT = script_dict)

conf_dict = {'%VERSION%': '1.2.3', '%BASE%': 'MyProg'}
env.Substfile('config.h.in', conf_dict, SUBST_DICT = conf_dict)

# UNPREDICTABLE - one key is a prefix of another
bad_foo = {'$foo': '$foo', '$foobar': '$foobar'}
env.Substfile('foo.in', SUBST_DICT = bad_foo)

# PREDICTABLE - keys are applied longest first
good_foo = [('$foobar', '$foobar'), ('$foo', '$foo')]
env.Substfile('foo.in', SUBST_DICT = good_foo)

# UNPREDICTABLE - one substitution could be futher expanded
bad_bar = {'@bar@': '@soap@', '@soap@': 'lye'}
env.Substfile('bar.in', SUBST_DICT = bad_bar)

# PREDICTABLE - substitutions are expanded in order
good_bar = (('@bar@', '@soap@'), ('@soap@', 'lye'))
env.Substfile('bar.in', SUBST_DICT = good_bar)

# the SUBST_DICT may be in common (and not an override)
substutions = {}
subst = Environment(tools = ['textfile'], SUBST_DICT = substitutions)
substitutions['@foo@'] = 'foo'
subst['SUBST_DICT']['@bar@'] = 'bar'
subst.Substfile('pgm1.c', [Value('#include "@foo@.h"'),
                           Value('#include "@bar@.h"'),
                           "common.in",
                           "pgm1.in"
                          ])
subst.Substfile('pgm2.c', [Value('#include "@foo@.h"'),
                           Value('#include "@bar@.h"'),
                           "common.in",
                           "pgm2.in"
                          ])

</example_commands>
</summary>
</builder>

<cvar name="LINESEPARATOR">
<summary>
<para>
The separator used by the &b-Substfile; and &b-Textfile; builders.
This value is used between sources when constructing the target.
It defaults to the current system line separator.
</para>
</summary>
</cvar>

<cvar name="SUBST_DICT">
<summary>
<para>
The dictionary used by the &b-Substfile; or &b-Textfile; builders
for substitution values.
It can be anything acceptable to the dict() constructor,
so in addition to a dictionary,
lists of tuples are also acceptable.
</para>
</summary>
</cvar>

<cvar name="SUBSTFILEPREFIX">
<summary>
<para>
The prefix used for &b-Substfile; file names,
the null string by default.
</para>
</summary>
</cvar>

<cvar name="SUBSTFILESUFFIX">
<summary>
<para>
The suffix used for &b-Substfile; file names,
the null string by default.
</para>
</summary>
</cvar>

<cvar name="TEXTFILEPREFIX">
<summary>
<para>
The prefix used for &b-Textfile; file names,
the null string by default.
</para>
</summary>
</cvar>

<cvar name="TEXTFILESUFFIX">
<summary>
<para>
The suffix used for &b-Textfile; file names;
<filename>.txt</filename> by default.
</para>
</summary>
</cvar>

</sconsdoc>