Port to libSass

[chriseppstein]

This issue will track the top level tasks that are required for Compass to be ported to libSass. When this issue is closed, we will release Compass 2.0.

Vision

Compass 2.0 will not use ruby and will run libSass for compilation by default. However, It will allow you to opt-in to using ruby sass.

TODO

• libcompass - a C++ library that can be used to compile a Sass file in a Compass-compatible Sass environment.
• compass compiled binaries for mac, linux, and windows that implements a large subset of the commands supported by the ruby compass command including a watcher and sprite generator.
• ruby ecosystem - Most compass extensions do not need to use ruby for much more than to self-register themselves. However, some do use ruby to define Sass functions. Obviously, this won't work going forward as it is implementation specific and it is not feasible to embed a ruby interpreter into libsass as most extensions expect not just a ruby language, but the ruby sass implementation specifics to be present. I think Lua may be a better language to allow Sass extensions in. It is trivial to embed a lua interpreter in both ruby and c++ and to creating bidirectional bindings of the public API that we want to expose to that environment.
• New config format. Either Sass introduces an extensible config format or compass creates one that is portable between both ruby and libsass. (probably start with compass and then if we like what we make, migrate that to sass as a standard. See: Project configuration for Sass sass/sass#1155)
• Decide if compass 2.0 should be written in Rust instead of C++ and simply use rust/c bindings to call out to libSass.
• Ensure that libSass is feature compatible with the features compass uses or dumb compass down to make it so. Especially around the importer architecture which in libsass seems to assume sass files on disk.
• Installer & upgrader - get updates to the binaries as well as the sass files and caniuse data.

[chriseppstein]

Please let's keep the comments on this issue on-topic. I appreciate the enthusiasm, but I need this to be a useful issue that can be used to discuss the work and track the issues so I will delete any +1 or other such comments that are intended to voice support or excitement. Feel free to send me a tweet if you need to emote as such.

[KittyGiraudel]

I will not be able to help with C or Rust, but once you have a working skeleton, you can count on me for extensive testing.

[saschaeggi]

Ping me if you need testers for this! This is huge! :)

[ritcheyer]

@chriseppstein This is fantastic news and would make many a Frontend Developer's Day! 😄 I know the nature of OSS timetables are…flexible but wondering if you have any ideas for when this may be completed?

(in light of your first comment, feel free to delete this)

[chriseppstein]

Sorry, no dates at this time.

[xzyfer]

I'm happy to lend any help I can in regards to Libsass. I'm also happy to contribute to compass c/rust side of things.

[chriseppstein]

An alternative approach would be to port Compass to Javascript and target only node-sass. This is less generally re-usable but it would make compass easier to contribute to. I'm still leaning towards having a core for compass that is statically compiled.

[chriseppstein]

I researched it and it turns out to not be that hard to embed resources like the sass files into a compiled binary. But it will require a custom importer to extract them from the executable without unpacking them -- though we will still need to provide a compass unpack compass like we do now which will put the compass stylesheets onto disk.

[lolmaus]

It would be too good if nobody were unhappy about this, right?

As a happy Ruby user, i'm very concerned with what will happen to Ruby Compass. The matter is that Compass is an umbrella term for a number of entities:

• A library of handy Sass mixins and functions.
• A standard for organizing Sass code in a project and a correpsonding configuration file.
• A command-line tool to create, compile and enhance projects.
• A standard for bundling Sass extensions.
• An ecosystem of those extensions and an effortless way to import them.
• A mean of effortlessly enhancing vanilla Sass functionality with custom behavior.

After you migrate Compass off Ruby, what will be left of that?

[chriseppstein]

The only aspect of compass here that will be called into question is:

A mean of effortlessly enhancing vanilla Sass functionality with custom behavior.

If by "effortlessly" you mean to ruby users using ruby code then that aspect will cease to exist. I hope to find a way for the "sass language" provide a standard mechanism for extensions that can be used in different implementations. I have started a conversation about this here: sass/sass#1608

[scottdavis]

we could even consider something like mruby: https://github.com/mruby/mruby

[klojniewski]

+1