hcatlin/libsass — pull request #349 by nsams (2014-05-03 08:53:16+00:00)
Title: implement NOT unary expression

I'm not sure if this implementation is correct, the comment for Unary_Expression suggests this is not the correct expression:
// Arithmetic negation (logical negation is just an ordinary function call).

Please comment how else it should be implemented...

See also https://github.com/hcatlin/sass-spec/pull/14