Merge pull request #1872 from mgreter/bugfix/issue_1709

Improve identifier schema to include variables

Author: mgreter

src/prelexer.cpp

@@ -195,15 +195,25 @@ namespace Sass {
                  sequence <
                    zero_plus <
                      alternatives <
-                       identifier,
+                       sequence <
+                         optional <
+                           exactly <'$'>
+                         >,
+                         identifier
+                       >,
                        exactly <'-'>
                      >
                    >,
                    interpolant,
                    zero_plus <
                      alternatives <
                        digits,
-                       identifier,
+                       sequence <
+                         optional <
+                           exactly <'$'>
+                         >,
+                         identifier
+                       >,
                        quoted_string,
                        exactly<'-'>
                      >