move handling of escaped variables and directives to the parser

Once text reaches the compiler, it is too late to parse escaped
variables and directives.  The compiler does not know where the text
came from, and can not determine when it should skip processing of
escape sequences for raw blocks.

Signed-off-by: R. Tyler Ballance <tyler@monkeypox.org>

cheetah/Compiler.py

@@ -428,27 +428,12 @@ def _appendToPrevStrConst(self, strConst):
         else:
             self._pendingStrConstChunks = [strConst]
 
-    def _unescapeCheetahVars(self, theString):
-        """Unescape any escaped Cheetah \$vars in the string.
-        """
-
-        token = self.setting('cheetahVarStartToken')
-        return theString.replace('\\' + token, token)
-
-    def _unescapeDirectives(self, theString):
-        """Unescape any escaped Cheetah \$vars in the string.
-        """
-
-        token = self.setting('directiveStartToken')
-        return theString.replace('\\' + token, token)
-
     def commitStrConst(self):
         """Add the code for outputting the pending strConst without chopping off
         any whitespace from it.
         """
         if self._pendingStrConstChunks:
-            strConst = self._unescapeCheetahVars(''.join(self._pendingStrConstChunks))
-            strConst = self._unescapeDirectives(strConst)
+            strConst = ''.join(self._pendingStrConstChunks)
             self._pendingStrConstChunks = []
             if not strConst:
                 return

cheetah/Parser.py

@@ -510,6 +510,19 @@ def _makePspREs(self):
         endTokenEsc = escapeRegexChars(endToken)
         self.PSPEndTokenRE = cachedRegex(escCharLookBehind + endTokenEsc)
 
+    def _unescapeCheetahVars(self, theString):
+        """Unescape any escaped Cheetah \$vars in the string.
+        """
+
+        token = self.setting('cheetahVarStartToken')
+        return theString.replace('\\' + token, token)
+
+    def _unescapeDirectives(self, theString):
+        """Unescape any escaped Cheetah directives in the string.
+        """
+
+        token = self.setting('directiveStartToken')
+        return theString.replace('\\' + token, token)
 
     def isLineClearToStartToken(self, pos=None):
         return self.isLineClearToPos(pos)
@@ -1497,6 +1510,8 @@ def eatPlainText(self):
             else:
                 self.advance()
         strConst = self.readTo(self.pos(), start=startPos)
+        strConst = self._unescapeCheetahVars(strConst)
+        strConst = self._unescapeDirectives(strConst)
         self._compiler.addStrConst(strConst)
         return match