SASS is a CSS pre-processor, a simplified version of the CSS language, with improved features and tools currently not included in the default standard.
Since the SASS compiler was written in Ruby, working with SASS automatically implies you should have a Ruby interpreter installed as well.
Since Ruby is not the most user friendlier language around and Python has a better adoption rate, isass is a project that has ported the basic features of the SASS compiler to Python.
This allows developers to compile SASS files to standards-compliant CSS from their Python CLI, without having to deal with the SASS or Ruby compilers in any way.
Currently isass supports the following SASS features: line extensions, comments, imports, variable substitutions, expressions, mix-ins, class extensions, and nesting.
isass supports CLI integration, manifest files, and even an automatic watchdog mechanism to monitor .sass files and automatically convert them to .css when changes are detected.
Under the hood, isass actually takes .sass files and converts them to .scss, and then uses pyScss to convert these files to actual .css files.
Comments not found