resolving @import

[tcurdt]

While the docs here are great https://github.com/stylus/stylus/blob/dev/docs/import.md they left me wondering how to control the loading/resolving of imports. I am using stylus on Node:

  var stylus = Stylus("....");
  stylus.set('filename', file.path);
  stylus.render(function(err, result){
    ...
  });

Is this possible at all?

[Panya]

What do you mean by "loading/resolving"?

[tcurdt]

I want to tell Stylus where to find the imports - or even provide them.

Similar to https://mozilla.github.io/nunjucks/api.html#loader or https://github.com/less/less-plugin-npm-import/blob/master/lib/npm-file-manager.js

[Panya]

I see. Unfortunately Stylus' importer is not extensible in this way currently.

[tcurdt]

@Panya Urgh - that's unexpected

Stylus has one of the nicest APIs from the other alternatives out there. So how do we fix this oversight? :)

If you guide me a little I might be able to help.

[tcurdt]

Seems like this is where things need to change a little
https://github.com/stylus/stylus/blob/dev/lib/visitor/deps-resolver.js#L112

[Panya]

It will be a little bit harder :) We need to extract default logic for importing files from the evaluator. These methods are importFile (messy) and visitImport.

[tcurdt]

@Panya well, that would have been too easy otherwise ;)

Maybe we start thinking about the API and then see how it could be implemented in those places.
Since I just looked at the various APIs of different libraries I have a pretty clear idea of what I would love to see:

resolve = function(absPathFrom, includeArgument, cb) {
  var absPathTo = path.resolve(absPathFrom, includeArgument);
  var content = fs.readFileSync(absPathTo, 'utf-8');
  cb(null, content);
}

The absPathFrom would be the absolute path of the file including and includeArgument the argument passed to the include statement.

Sounds sane?

[Panya]

Yep, but you also need to know that all internal Stylus' processes are currently synchronous, so that would limit the functionality to synchronous-only resolvers (otherwise we need to go deeper :)).

[tcurdt]

Synchronous is fine - for me, for now :)
I would still use callback style for the API though

[SamHwang1990]

Hi~~~
Is there any ways to allow optinal @import file like less?
The mainly purpose of this demand is to let stylus to import a file which may be not existed without throwing error.

[tcurdt]

@SamHwang1990 that sounds like a very different issue. Better open an individual issue for it.

[tcurdt]

@Panya tag as enhancement request?

I will see if I can find some time to dig into this (fingers crossed) but as less and sass is working fine the urge is not that strong. Would love to support stylus though.

[SamHwang1990]

Sorry about my comment~~~
I have open a new issue about it. #2041
Thank you! @tcurdt