NAME

NAME

CSS::Minifier::XS - XS based CSS minifier

SYNOPSIS

use CSS::Minifier::XS qw(minify);
my $css = '...';
my $minified = minify($css);

DESCRIPTION

CSS::Minifier::XS is a CSS "minifier"; its designed to remove
unnecessary whitespace and comments from CSS files, while also not
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.

METHODS

minify($css)

Minifies the given $css, returning the minified CSS back to the
caller.

HOW IT WORKS

CSS::Minifier::XS minifies the CSS by removing unnecessary whitespace
from CSS documents. Comment blocks are also removed, except when (a)
they contain the word "copyright" in them, or (b) they're needed to
implement the "Mac/IE Comment Hack".

Internally, the minification is done by taking multiple passes through
the CSS document:

Pass 1: Tokenize

First, we go through and parse the CSS document into a series of tokens
internally. The tokenizing process does not check to make sure that
you've 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 they're still included in
the final results we only want to include them at their shortest.

Whitespace

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

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

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 unnecessary
tokens.

Whitespace

Wherever possible, whitespace is removed; before+after comment
blocks, and before+after various symbols/sigils.

Comments

Comments that either (a) are needed to implement the "Mac/IE Comment
Hack", or that (b) contain the word "copyright" in them are
preserved. All other comments are removed.

Symbols/Sigils

Semi-colons that are immediately followed by a closing brace (e.g.
";}") are removed; semi-colons are needed to separate multiple
declarations, but aren't required at the end of a group.

Everything else

We keep everything else; identifiers, quoted literal strings,
symbols/sigils, etc.

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.

AUTHOR

Graham TerMarsch ([email protected])

COPYRIGHT

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.

SEE ALSO

CSS::Minifier.