173 lines
6.4 KiB
Plaintext
173 lines
6.4 KiB
Plaintext
.. copyright:
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Copyright 2011 - 2015
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André Malo or his licensors, as applicable
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.. license:
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==============================
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rJSmin - Javascript Minifier
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==============================
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|**rJSmin**| is a javascript minifier written in python.
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The minifier is based on the semantics of `jsmin.c by Douglas Crockford`_\.
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The module is a re-implementation aiming for :doc:`speed <benchmark>`, so it
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can be used at runtime (rather than during a preprocessing step). Usually it
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produces the same results as the original ``jsmin.c``. It differs in the
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following ways:
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- there is no error detection: unterminated string, regex and comment
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literals are treated as regular javascript code and minified as such.
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- Control characters inside string and regex literals are left untouched; they
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are not converted to spaces (nor to \\n)
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- Newline characters are not allowed inside string and regex literals, except
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for line continuations in string literals (ECMA-5).
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- "``return /regex/``" is recognized correctly.
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- Line terminators after regex literals are handled more sensibly.
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- "``+ +``" and "``- -``" sequences are not collapsed to '``++``' or
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'``--``'
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- Newlines before ``!`` operators are removed more sensibly
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- Comments starting with an exclamation mark ('``!``') can be kept optionally
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- |rJSmin| does not handle streams, but only complete strings. (However, the
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module provides a "streamy" interface).
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Since most parts of the logic are handled by the regex engine it's way
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faster than the original python port of ``jsmin.c`` by Baruch Even. The speed
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factor varies between about 6 and 55 depending on input and python version
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(it gets faster the more compressed the input already is). Compared to the
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speed-refactored python port by Dave St.Germain the performance gain is less
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dramatic but still between 3 and 50 (for huge inputs).
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|rjsmin| comes with an optional C-reimplementation of the python/regex
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implementation, which speeds up the minifying process even more.
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|rjsmin| works with both python 2 (starting with python 2.4) and python 3.
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.. _jsmin.c by Douglas Crockford: http://www.crockford.com/javascript/jsmin.c
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Documentation
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~~~~~~~~~~~~~
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A :rjsmin:`generated API documentation </>` is available. But you can
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just look into the module. It provides a simple function, called
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``jsmin`` which takes the script as a string and returns the minified
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script as a string.
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The module additionally provides a "streamy" interface similar to the
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one jsmin.c provides:
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.. sourcecode:: console
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$ python -mrjsmin <script >minified
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It takes two options:
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-b Keep bang-comments (Comments starting with an exclamation mark)
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-p Force using the python implementation (not the C implementation)
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Development Status
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~~~~~~~~~~~~~~~~~~
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|rjsmin| is stable.
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License
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~~~~~~~
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|rjsmin| is available under the terms and conditions of the "Apache License,
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Version 2.0." You'll find the detailed licensing terms in the root
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directory of the source distribution package or online at
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`http://www.apache.org/licenses/LICENSE-2.0
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<http://www.apache.org/licenses/LICENSE-2.0>`_.
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.. placeholder: Download
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Bugs
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~~~~
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No bugs, of course. ;-)
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But if you've found one or have an idea how to improve |rjsmin|, feel free
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to send a pull request on `github <https://github.com/ndparker/rjsmin>`_
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or send a mail to <rjsmin-bugs@perlig.de>.
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Author Information
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~~~~~~~~~~~~~~~~~~
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|rjsmin| was written and is maintained by André Malo.
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Acknowledgements
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----------------
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- `Douglas Crockford <http://www.crockford.com/>`_
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- `Jeffrey Friedl <http://regex.info/>`_
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Trivia / Fun
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~~~~~~~~~~~~
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|rJSmin| is a single pass substitution using a simple regular expression,
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which looks like this:
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.. sourcecode:: text
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pattern = (
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r'([^\047"/\000-\040]+)|((?:(?:\047[^\047\\\r\n]*(?:\\(?:[^\r\n]'
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r'|\r?\n|\r)[^\047\\\r\n]*)*\047)|(?:"[^"\\\r\n]*(?:\\(?:[^\r\n]'
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r'|\r?\n|\r)[^"\\\r\n]*)*"))[^\047"/\000-\040]*)|(?<=[(,=:\[!&|?'
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r'{};\r\n])(?:[\000-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*'
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r'][^*]*\*+)*/))*(?:(?:(?://[^\r\n]*)?[\r\n])(?:[\000-\011\013\0'
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r'14\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/))*)*((?:/(?![\r'
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r'\n/*])[^/\\\[\r\n]*(?:(?:\\[^\r\n]|(?:\[[^\\\]\r\n]*(?:\\[^\r'
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r'\n][^\\\]\r\n]*)*\]))[^/\\\[\r\n]*)*/))((?:[\000-\011\013\014'
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r'\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/))*(?:(?:(?://[^\r'
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r'\n]*)?[\r\n])(?:[\000-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:'
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r'[^/*][^*]*\*+)*/))*)+(?=[^\000-\040&)+,.:;=?\]|}-]))?|(?<=[\00'
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r'0-#%-,./:-@\[-^`{-~-]return)(?:[\000-\011\013\014\016-\040]|(?'
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r':/\*[^*]*\*+(?:[^/*][^*]*\*+)*/))*((?:/(?![\r\n/*])[^/\\\[\r\n'
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r']*(?:(?:\\[^\r\n]|(?:\[[^\\\]\r\n]*(?:\\[^\r\n][^\\\]\r\n]*)*'
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r'\]))[^/\\\[\r\n]*)*/))((?:[\000-\011\013\014\016-\040]|(?:/\*['
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r'^*]*\*+(?:[^/*][^*]*\*+)*/))*(?:(?:(?://[^\r\n]*)?[\r\n])(?:['
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r'\000-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/)'
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r')*)+(?=[^\000-\040&)+,.:;=?\]|}-]))?|(?<=[^\000-!#%&(*,./:-@\['
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r'\\^`{|~])(?:[\000-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*'
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r'][^*]*\*+)*/))*(?:((?:(?://[^\r\n]*)?[\r\n]))(?:[\000-\011\013'
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r'\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/))*)+(?=[^\000'
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r'-\040"#%-\047)*,./:-@\\-^`|-~])|(?<=[^\000-#%-,./:-@\[-^`{-~-]'
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r')((?:[\000-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*'
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r'\*+)*/)))+(?=[^\000-#%-,./:-@\[-^`{-~-])|(?<=\+)((?:[\000-\011'
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r'\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/)))+(?=\+)'
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r'|(?<=-)((?:[\000-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*]'
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r'[^*]*\*+)*/)))+(?=-)|(?:[\000-\011\013\014\016-\040]|(?:/\*[^*'
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r']*\*+(?:[^/*][^*]*\*+)*/))+|(?:(?:(?://[^\r\n]*)?[\r\n])(?:[\0'
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r'00-\011\013\014\016-\040]|(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/))*'
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r')+'
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)
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Related
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~~~~~~~
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- `CSS Minifier rCSSmin <http://opensource.perlig.de/rcssmin/>`_
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.. vim: ft=rest tw=72
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