URL support

[terinjokes]

Continuing the discussion from #18 (comment)

---

It would be nice if Compass's URL functions were implemented, even if it comes down to variables we need to set before importing compass-mixins.

[Zauberfisch]

I think defining them in a .scss file is ok for the time being.
after all, if you want to configure them with compass, you would define them in the file config.rb, makes little difference to define them in a _config.scss here.

also, let me state here, the url function set is one of the most important features of compass to me, so I hope to see them in this repository soon ;)

[michaek]

I'm still not sure this makes sense to port. If you want to prepend a variable, this is really simple:

$compass-image-path: 'your/image/path' !default;
@function image-url($path) {
  @return "#{$compass-image-path}/#{$path}";
}

I don't want to rule it out, but I'm not yet convinced.

[terinjokes]

@michaek These mixins already use the url functions from Compass, without defining them, so they just appear unprocessed in the output.

[OnkelTem]

Hm... can't we just define lacking functions in js?

UPDATE. Sorry, I forgot that I'm not in node-sass' issue queue :)

[michaek]

I agree it's strange to not support everything from Compass, but this is a library that seeks to go halfway, as it would be prohibitive to support all of Compass. I'd say its intention is to provide a crutch to get to the point where your project no longer depends on Compass.

[gaomd]

@michaek The missing image-url() confused me, I believe I'm not alone, maybe we should note the incompleteness in the README.md.