CSS compressor written in OCaml

Taddeus Kroes bf099c1049 Bugfix in color conversion 11 tahun lalu
dist 675f641463 Updated README some more, added 64-bit pre-compiled binary 11 tahun lalu
.gitignore 6ee79d6b7b Cleanup 11 tahun lalu
Makefile 675f641463 Updated README some more, added 64-bit pre-compiled binary 11 tahun lalu
README.md 675f641463 Updated README some more, added 64-bit pre-compiled binary 11 tahun lalu
color_names.ml bf099c1049 Bugfix in color conversion 11 tahun lalu
duplicates.ml d36f52bf3f Implemented duplicate declaration pruning 11 tahun lalu
lexer.mll aaaf2601ed Fixed support for @-<prefix>-keyframes syntax 11 tahun lalu
main.ml 0f0ddfeda0 Forgot newline in usage message 11 tahun lalu
parse.ml 70f032a31d Lexer now correctly tracks line numbers + some general cleanup 11 tahun lalu
parser.mly 3b7dc07458 Extended 'Simple' selector type to algebraic data types 11 tahun lalu
selector.ml 099cdb0189 Renamed a file 11 tahun lalu
shorthand.ml 2406d894cf Improved shorthand folding when component expressions are !important 11 tahun lalu
simple.ml bf099c1049 Bugfix in color conversion 11 tahun lalu
stringify.ml bed50c9bba Minified numbers are now rounded to 2 decimal digits 11 tahun lalu
types.ml 43ee471f69 Changed main function for minimal command-line usage (just simple minification operations, for now) 11 tahun lalu
util.ml 5003457c8a Added --sort option 11 tahun lalu

README.md

About

mincss is an extendible CSS minifier written in OCaml. It features a complete parser for the CSS3 language, along with type definitions that are consistent with the official CSS specification and a traversal utility function for use in transformation passes.

Installation

For now, there is no easy installation option for mincss (yet). A pre-built 64-bit ELF binary is available for download here. You can also build the binary from source (see Building mincss below).

Features

Whitespace compression

a,                                  |  a,.myclass [class~="foo"]>p{color:#fff}
.myclass [class ~= "foo"] >  p {    |
    color: #fff;                    |
}                                   |

Compression of simple expressions

color: white;                       |  color: #fff;
font-weight: normal;                |  font-weight: 400;

Generation of shorthand properties

font-weight: normal;                |  font: normal 12px/15px sans-serif;
font-size: 12px;                    |
line-height: 15px;                  |
font-family: sans-serif;            |

Any existing shorthands are first unfolded into their non-shorthand counterparts, after which the last value is used for shorthand generation:

font: normal 12px/15px sans-serif;  |  font: bold 12px/15px sans-serif;
font-weight: bold;                  |

Sorting declarations

The --sort command-line option sorts declarations alphabetically. This option is disabled by default since it does not affect file size.

Command-line interface

Output of mincss -h:

Usage: ./mincss [<options>] [<file> ...]

Generic options:
 -h, --help        Show this help message
 -v, --verbose     Verbose mode: show compression rate
 -o <file>         Output file (defaults to stdout)
 <file> ...        Input files (default is to read from stdin)

Optimization flags (if none are specified, all are enabled):
 -w, --whitespace  Eliminate unnecessary whitespaces (has the greatest effect, omit for pretty-printing)
 -c, --simple      Shorten colors and font weights
 -s, --shorthands  Generate shorthand properties
 -d, --duplicates  Prune duplicate properties (WARNING: may affect cross-browser hacks)
 -p, --pretty      Shorthand for -c -s -d
 -e, --echo        Just parse and pretty-print, no optimizations

Formatting options:
 --sort            Sort declarations in each selector group

Building mincss

Dependencies are OCaml 4.0 and menhir.

Bootstrapping on a Debian system can be done as follows:

$ sudo apt-get install ocaml opam git
$ opam init
$ opam switch 4.01.0
$ opam install menhir
$ git clone git@github.com:taddeus/mincss.git
$ cd mincss
$ make
$ ./mincss --help