Add t_tilde token for '~'

To be used inside general_sibling_selector (e.g. 'a ~ b { ... }')
instead of the literal '~'. Necessary since we had to remove the literal
from the lexer in order to tokenize ~"..." and ~'...'.

lesscpy/lessc/lexer.py

@@ -53,6 +53,7 @@ class LessLexer:
         't_popen',
         't_pclose',
         't_semicolon',
+        't_tilde',
 
         't_lsopen',
         't_lsclose',
@@ -234,6 +235,10 @@ class LessLexer:
             t.lexer.push_state('lessstringapostrophe')
         return t
 
+    def t_t_tilde(self, t):
+        r'~'
+        return t
+
     def t_lessstringquotes_less_variable(self, t):
         r'@\{[^@"\}]+\}'
         return t

lesscpy/lessc/parser.py

@@ -797,8 +797,8 @@ class LessParser(object):
         p[0] = tuple(list(p)[1:])
 
     def p_general_sibling_selector(self, p):
-        """ general_sibling_selector  : '~' t_ws
-                                      | '~'
+        """ general_sibling_selector  : t_tilde t_ws
+                                      | t_tilde
         """
         p[0] = tuple(list(p)[1:])