Runtime support for pre-processor stylesheets

[lkraav]

Pre-processor advantages are probably obvious for everyone.

Idea is for the plugin to automatically compile and cache all enqueued pre-processor stylesheets, like LESS or SCSS, determined by the file name extension.

I'm familiar with only LESS for now, so that's my own contribution goal.

I would be modeling the solution ​after this well working WP-LESS plugin from WordPress world.

Problem spot might be finding a Python LESS compiler of adequate quality. Pointers welcome.

Leave a comment if you're interested in having such a tool.

Rationale for including this in ThemeEnginePlugin: seems like a natural fit. Trac developer resources are scarce, so I'd rather avoid fragmentation.

[lkraav]

Explain integration

[Ryan J Ollos]

Is ​trac:#10672 asking for the same thing? I think we can work on getting that ticket into the Trac core in one of the next major releases.

[lkraav]

Hmm, it's at least related, possibly in the early request plumbing part. But in the interest of keeping scope reasonable for both, it is likely not be a good idea to combine these into one effort. I think "feature as a plugin" start is better here to see how it all works out. Based on my WP experience, solid dep. min. functionality is not trivial to code at all.

[Olemis Lang]

I'll start working on this one without accepting ticket , see #11457

I'll add interfaces to plug the css pre processor of choice by a given theme (e.g. sass, scss , ... , less) and will definitely incorporate default implementation for the later (since it's used by Bloodhound theme powered by Bootstrap) .

Initially only TRAC_ADMIN users will be able to configure such aspects (see #6433). This feature will be available then should a third party component implement the appropriate interface to support a given syntax . Only a single (theme-specific) css file will be compiled this way e.g. bootstrap.css

I plan to support customization of the following aspects :

• variables
• mixins

Compilation process will actually happen in the server side, therefore a python compiler is needed.

@lkraav : please mention if the aspects mentioned above are ok for you.

OTOH could you please choose one of these libs ?

• ​lesscpy
• ​metalshark:lesscss-python

It'd be nice if you could provide sample code that you'd prefer to achieve best possible generation.

TBH I've found more robust py libs for sass than I did for less e.g.

• ​scss
• ​dahlia:libsass-python
• ​sass
• ​isass
• ​sassin
• ​pylibsass
• ...

[lkraav]

Your plan seems solid.

​https://github.com/robotis/Lesscpy/pull/28 gives me confidence in the first option. Repo is active and moving forward. Now Python 3 vs 2 may become an issue?

metalshark's stuff seems hopeLESSly outdated.

[Olemis Lang]

ok , I'll try to get something done with it once target pull request will be merged upstream . /me subscribing to that thread , thnx .