Refactor/directive parsing

[mgreter]

Spec test sass/sass-spec#764 (excerpt from #1900, fixes #1233)

• libsass-todo-issues\issue_1233\expected.nested
• libsass-todo-tests\scss-tests\127_test_moz_document_interpolation\expected.nested
• libsass-todo-tests\libsass\moz-document\basic\expected.nested
• libsass-todo-tests\libsass\moz-document\interpolated\expected.nested

[xzyfer]

If you're going to make this massive of a change I suggest doing your best to move more inline with Ruby Sass implementation like with cssize.

The closer our internal data flow and logic is to Ruby the easier it's going to be keep features in sync, and prevent weird edge cases.

[mgreter]

If you check the commits this is exactly what is happening here (see prelexer)!

[xzyfer]

I wasn't insinuating it wasn't what you were doing. I just wanted to make sure we were on the same page.

[mgreter]

Just assumed, because the main reason why this change is that massive is because it is following ruby sass closely in the first place 😉

[mgreter]

Just to be clear, I agree to follow ruby sass closely when it comes to the parser and the internal ast in general. But we can (and should) do better in libsass with manipulation and processing. I guess ruby sass choose to do quite a few operations (I'm specially refering to extend) in a monolithic approach. This makes sense in a language with dynamic function dispatching, since adding to many method calls in tight loops (code hotspots) can lead to bad performance. We don't have this constraint in c++ and should embrace the possibility of micro functions for selector manipulations. Another reason for that is that writing big monolithic functions in C++ (or any strict types language for that matter) tends to get tiresome, specially when a lot of loops are involved. But so far extend works and I don't want to touch any of that directly ported Node class if possible. Which reminds me of #1392 ...

[xzyfer]

I agree. I tend to avoid the extend code this exact reason.

[xzyfer]

You'll probably have to rebase your sass-spec branch of master.

[coveralls]

Coverage decreased (-0.3%) to 78.949% when pulling 83d401b on mgreter:refactor/directive-parsing into 57fbfb9 on sass:master.