Several vast improvements to string parsing.

- Interpolation is now understood by the parser!  It works for
  barewords, quoted strings, and both forms of URL.

- Escaped characters are now understood and translated by the parser as
  well!

- Rendering strings to CSS attempts to escape them correctly, regardless
  of how they were put together.

- The block locator (at least the Python version) is now a little more
  aware of CSS escaping.

Unfortunately there are some problems with the C module in this commit,
which I will be promptly fixing.

Conflicts:
	scss/blockast.py

1 files changed, 1 insertions, 1 deletions

diff --git a/scss/errors.py b/scss/errors.py
index b1e7f12..8be3019 100644
--- a/scss/errors.py
+++ b/scss/errors.py
@@ -213,7 +213,7 @@ class SassParseError(SassError):
 
     def format_prefix(self):
         decorated_expr, line = add_error_marker(self.expression, self.expression_pos or -1)
-        return """Error parsing expression:\n{0}\n""".format(decorated_expr)
+        return """Error parsing expression at {1}:\n{0}\n""".format(decorated_expr, self.expression_pos)
 
 
 class SassEvaluationError(SassError):