FAST-CSS

FAST-CSS is a recently created project that integrates with Moose and leverages the Tree-Sitter parser to analyze CSS source code in Pharo.

Features

FAST-CSS relies on:

• FAST, to ensure compatibility with Moose.
• Pharo-Tree-Sitter, implemented in Pharo via the FFI protocol to efficiently parse CSS source code. It is also used to do incremental parsing.

FAST-CSS metamodel is defined in a way where nodes align with those generated by Tree-Sitter.

Installation

To load FAST-CSS in Pharo, execute the following in a Moose image:

Metacello new  
  baseline: 'FASTCSS';  
  repository: 'github://Evref-BL/FAST-CSS:main';  
  load.

Usage

To use it, please ensure that you have installed the corresponding libraries for Tree Sitter on your machine, to ensure parsing succeeds. Normally, this has been automated for different operating systems. But for more details, you can have a look at this blog-post.

To use it in Pharo, you can check example below:

res := FASTCSSImporter new parse:  'body {
  background-color: linen;
}'. 

NB

The project is updated starting October 1 2026. It works on Moose 12+. The metamodel is complete following the description of tree sitter css original repo.

If you think an update is recommended or new feature is requested ... Your contribution is more than welcome. Happy coding with Pharo and CSS :)