Manual Reference Pages - CSS::MINIFIER::XS (3)
CSS::Minifier::XS - XS based CSS minifier
use CSS::Minifier::XS qw(minify);
$minified = minify($css);
CSS::Minifier::XS is a CSS minifier; its designed to remove un-necessary
whitespace and comments from CSS files, while also <B>notB> breaking the CSS.
CSS::Minifier::XS is similar in function to CSS::Minifier, but is
substantially faster as its written in XS and not just pure Perl.
Minifies the given $css, returning the minified CSS back to the caller.
HOW IT WORKS
CSS::Minifier::XS minifies the CSS by removing un-necessary whitespace from
CSS documents. Comment blocks are also removed, except when (a) they
contain the word copyright in them, or (b) theyre needed to implement the
Mac/IE Comment Hack.
Internally, the minification is done by taking multiple passes through the CSS
Pass 1: Tokenize
First, we go through and parse the CSS document into a series of tokens
internally. The tokenizing process <B>does notB> check to make sure that youve
got syntactically valid CSS, it just breaks up the text into a stream of tokens
suitable for processing by the subsequent stages.
Pass 2: Collapse
We then march through the token list and collapse certain tokens down to their
smallest possible representation. If theyre still included in the final
results we only want to include them at their shortest.
Runs of multiple whitespace characters are reduced down to a single whitespace
character. If the whitespace contains any end of line (EOL) characters, then
the end result is the first EOL character encountered. Otherwise, the
result is the first whitespace character in the run.
Comments implementing the Mac/IE Comment Hack are collapsed down to the
smallest possible comment that would still implement the hack (/*\*/ to start
the hack, and /**/ to end it).
Zero Units (e.g. 0px) are reduced down to just 0, as the CSS specification
indicates that the unit is not required when its a zero value.
Pass 3: Pruning
We then go back through the token list and prune and remove un-necessary
Wherever possible, whitespace is removed; before+after comment blocks, and
before+after various symbols/sigils.
Comments that either (a) are needed to implement the Mac/IE Comment Hack, or
that (b) contain the word copyright in them are preserved. <B>AllB> other
comments are removed.
Semi-colons that are immediately followed by a closing brace (e.g. ;}) are
removed; semi-colons are needed to separate multiple declarations, but arent
required at the end of a group.
We keep everything else; identifiers, quoted literal strings, symbols/sigils,
Pass 4: Re-assembly
Lastly, we go back through the token list and re-assemble it all back into a
single CSS string, which is then returned back to the caller.
Graham TerMarsch (email@example.com)
Please report bugs via RT
and be sure to include the CSS that youre having troubles minifying.
Copyright (C) 2007-, Graham TerMarsch. All Rights Reserved.
This is free software; you can redistribute it and/or modify it under the same
license as Perl itself.
|perl v5.20.3 ||CSS::MINIFIER::XS (3) ||2013-10-31 |
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