PROCSS

A simple CSS parsing and transformation framework.

Docs

Developer Setup

Build

cargo xbuild

Test

cargo xtest

Test coverage report (disables incremental builds)

cargo xtest --coverage

Lint

cargo clippy

Bench

cargo xbench

Generate docs (output at ./target/doc/procss/index.html)

cargo doc

lib.rs:

A simple CSS parsing and transformation framework. Procss can be used to quickly bundle a collection of CSS+ files, or write your own custom transforms.

Usage

Procss's parser understands a nested superset of CSS (which we refer to as CSS+), similar to the CSS nesting proposal, or languages like Sass. Start with source CSS+ as a [str], use [crate::parse] or [crate::parse_unchecked] to generate an [ast::Tree].

use procss::{ast, parse};

let ast = procss::parse("div{.open{color:red;}}").unwrap();

The resulting [ast::Tree] can be converted to a de-nested [ast::Css] with the [ast::Tree::flatten_tree] method, which itself can then be rendered as a plain browser-readable CSS string via the [RenderCss::as_css_string] trait method.

# use procss::{parse, ast};
# let ast = procss::parse("div{.open{color:red;}}").unwrap();
use procss::RenderCss;

let flat: ast::Css = ast.flatten_tree();
let css: String = flat.as_css_string();
assert_eq!(css, "div .open{color:red;}");

Intermediate structs [ast::Css::transform] amd [ast::Tree::transform] can be used to recursively mutate a tree for a variety of node structs in the [ast] module. Some useful Example of such transforms can be found in the [transformers] module.

# use procss::{parse, RenderCss};
use procss::transformers;

let test = "
@mixin test {color: red;}
div {@include test;}
";

let mut ast = procss::parse(test).unwrap();
transformers::apply_mixin(&mut ast);
let flat = ast.flatten_tree().as_css_string();
assert_eq!(flat, "div{color:red;}");

For coordinating large builds on a tree of CSS files, the [BuildCss] struct can parse and minify, applying all transforms (including [transformers::apply_import]) as the compilation is left-folded over the inputs.

let mut build = procss::BuildCss::new("./src");
build.add_file("controls/menu.scss");
build.add_file("logout.scss"); // imports "controls/menu.scss"
build.add_file("my_app.scss"); // imports "controls/menu.scss" and "logout.scss"
build.compile().unwrap().write("./dist").unwrap();