Interpolated import does not work with url expressions

[SomMeri]

Following less fragment:

... blah ...
@import url(@{directory}flagged-varmix-fifth.less);
... blah ...

returns this error:

c:\data\meri\less4java\commandLineLess\node.js-1.6.0>lessc test.less FileError: '@{directory}flagged-varmix-fifth.less' wasn't found in c:\data\meri\less4java\commandLineLess\node.js-1.6.0\test.less on line 13, column 1:
12 @import "@{directory}flagged-varmix-fourth.less";
13 @import url(@{directory}flagged-varmix-fifth.less);
14 .mixinFactory(sixth);

workaround:

... blah ...
@import "@{directory}flagged-varmix-fifth.less";
... blah ...

[lukeapage]

as designed - we don't interpolate in unquoted url functions. I'm sure this case up a couple of days ago but I cannot find it.
Unquoted urls are a source of hell because they operate their own grammar outside of everything else

url(// comment \) or not? oh look I can escape quotes and brackets outside of quotes\");

I'm not even sure if we even support the above.

[seven-phases-max]

I'm sure this case up a couple of days ago but I cannot find it.

I guess that was this one: #1863

[lukeapage]

Ah yes it was the 2nd part of that yes.

@SomMeri do you think this should work or was this just a question? If its a question we can just close ;)

[SomMeri]

@SomMeri We can consider it just a question. I expected it to work, so I opened issue.I do not expect it to work anymore, so all is good :).

[matthew-dean]

Is there a reason we cannot consider url(" synonymous with url(? The regex can't treat the starting (and ending) quote as optional and everything between url( and ) a string?

[lukeapage]

@matthew-dean the escaping rules are different - not just for parsing but for output too. In addition the logic for replacing variables is in quoted (which is why variable interpolation outside of strings doesn't work apart from where custom code is written - selectors, properties).
It could work like this, but unquoted urls are a pain in the arse and it would make the code more complicated and things more tricky, for very little benefit (IMO... Because of the escaping rules I would say that quoting url's is good practice, certainly within Less).