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lassweb

Common Lisp is a good language to write various domain-specific languages (DSLs). This library provides a DSL that compiles into the CSS.

Lass is the lisp community's response to Sass, LESS and Stylus.

Here is a short example:

POFTHEDAY> (lass:compile-and-write
            '(nav
              (ul
               :list-style none
               (li
                :margin 0 :padding 0
                :display inline-block))))
"
nav ul{
    list-style: none;
}

nav ul li{
    margin: 0;
    padding: 0;
    display: inline-block;
}"

As you can see, definitions can be nested. Also, you can use variables the same way as you do when writing macroses.

Another cool feature is flexible selectors, which can be used to make a definition more concise:

POFTHEDAY> (lass:compile-and-write
            '((:and
               (:or article section)
               (:= data-author (:or yukari ran chen))
               (:nth-child (:or 1 2 3)))
              :display none))

"article[data-author=\"yukari\"]:nth-child(1),
article[data-author=\"yukari\"]:nth-child(2),
article[data-author=\"yukari\"]:nth-child(3),
article[data-author=\"ran\"]:nth-child(1),
article[data-author=\"ran\"]:nth-child(2),
article[data-author=\"ran\"]:nth-child(3),
article[data-author=\"chen\"]:nth-child(1),
article[data-author=\"chen\"]:nth-child(2),
article[data-author=\"chen\"]:nth-child(3),
section[data-author=\"yukari\"]:nth-child(1),
section[data-author=\"yukari\"]:nth-child(2),
section[data-author=\"yukari\"]:nth-child(3),
section[data-author=\"ran\"]:nth-child(1),
section[data-author=\"ran\"]:nth-child(2),
section[data-author=\"ran\"]:nth-child(3),
section[data-author=\"chen\"]:nth-child(1),
section[data-author=\"chen\"]:nth-child(2),
section[data-author=\"chen\"]:nth-child(3){
    display: none;
}"

Another great feature is support for browser-specific prefixes. Lass will expand to them, keeping your code clean:

POFTHEDAY> (lass:compile-and-write
            '(.fun
              :linear-gradient "deg(45)" black 0% darkgray 100%
              :transform rotate -45deg))
".fun{
    background: -moz-linear-gradient(deg(45), black 0%, darkgray 100%);
    background: -o-linear-gradient(deg(45), black 0%, darkgray 100%);
    background: -webkit-linear-gradient(deg(45), black 0%, darkgray 100%);
    background: -ms-linear-gradient(deg(45), black 0%, darkgray 100%);
    background: linear-gradient(deg(45), black 0%, darkgray 100%);
    -moz-transform: rotate(-45deg);
    -o-transform: rotate(-45deg);
    -webkit-transform: rotate(-45deg);
    -ms-transform: rotate(-45deg);
    transform: rotate(-45deg);
}"

This library has very good documentation:

http://quickdocs.org/lass/

Thanks, @shinmera!