Docs.rs Ferris by PRO-2684

/* ==UserStyle==
@name           Docs.rs Ferris
@namespace      github.com/PRO-2684
@version        0.1.0
@description    Show Ferris the crab on `docs.rs` code examples, just like on the Rust book.
@author         PRO-2684
@license     	gpl-3.0
@preprocessor   stylus
@var checkbox   ShowAttributes        "Show attributes"         0
@var checkbox   UndesiredIgnore       "Show Ferris on `ignore`" 0
@var checkbox   UndesiredNoRun        "Show Ferris on `no_run`" 0
@var number     Opacity               "Opacity (%)"             [100, 0, 100, 1]
@var number     Size                  "Size (em)"               [4.5, 0, 10, 0.1]
@var number     Right                 "Right offset (em)"       [0.3, 0, 5, 0.1]
@var number     Top                   "Top offset (em)"         [2.5, 0, 5, 0.1]
==/UserStyle== */

@-moz-document domain("docs.rs") {
    SVG_ROOT = "https://doc.rust-lang.org/book/img/ferris/";
    DOES_NOT_COMPILE = SVG_ROOT + "does_not_compile.svg";
    PANICS = SVG_ROOT + "panics.svg";
    NOT_DESIRED_BEHAVIOR = SVG_ROOT + "not_desired_behavior.svg";

    MAPPING = {
        "should_panic": PANICS,
        "compile_fail": DOES_NOT_COMPILE,
        "ignore": UNDESIRED_IGNORE ? NOT_DESIRED_BEHAVIOR : "",
        "no_run": UNDESIRED_NO_RUN ? NOT_DESIRED_BEHAVIOR : "",
    };

    .example-wrap {
        for key, value in MAPPING {
            if ShowAttributes {
                &.{key}::before {
                    content: key;
                }
            }
            if value != "" {
                &.{key}::after {
                    background-image: url(value);
                }
            }
        }
        &::before {
            position: absolute;
            left: 1em;
            color: gray;
        }
        &::after {
            display: block;
            content: "";
            position: absolute;
            width: unit(Size, "em");
            height: unit(Size, "em");
            right: unit(Right, "em");
            top: unit(Top, "em");
            background-size: contain;
            background-repeat: no-repeat;
            opacity: unit(Opacity, "%");
        }
    }
}