Separate this out into a METALCompiler and TALCompiler class.

The output of both has the same form, and most be interpreted using
the TALInterpreter class.  However the METALCompiler output only
does (METAL) macro expansion and leaves everything else (i.e. TAL
statements) alone.

lib/python/TAL/TALCompiler.py

@@ -83,10 +83,10 @@
 # 
 ##############################################################################
 """
-Compile a DOM tree for efficient TAL expansion.
+Compile a DOM tree for efficient METAL and TAL expansion.
 
 XXX TO DO:
-- get macro use/define substitution right (currently ignores prefix)
+- get macro define->use substitution in output right (currently ignores prefix)
 """
 
 import string
@@ -100,7 +100,7 @@ from TALVisitor import macroIndexer, slotIndexer
 from TALVisitor import splitParts, parseAttributeReplacements
 from TALVisitor import parseSubstitution
 
-class TALCompiler(DOMVisitor):
+class METALCompiler(DOMVisitor):
 
     def __init__(self, document):
         DOMVisitor.__init__(self, document)
@@ -151,7 +151,7 @@ class TALCompiler(DOMVisitor):
             if attr.namespaceURI:
                 if self.newNS(attr.prefix, attr.namespaceURI):
                     list.append(("xmlns:" + attr.prefix, attr.namespaceURI))
-        list.extend(getAttributeList(node))
+        list.extend(self.getAttributeList(node))
         return list
 
     def emit(self, *instruction):
@@ -214,6 +214,49 @@ class TALCompiler(DOMVisitor):
             return
         self.compileElement(node)
 
+    def compileElement(self, node):
+        self.emitElement(node)
+
+    def emitElement(self, node):
+            if not node.hasChildNodes():
+                self.emitStartEndTag(node)
+            else:
+                self.emitStartTag(node)
+                self.visitAllChildren(node)
+                self.emitEndTag(node)
+
+    def visitText(self, node):
+        self.emit("text", node.nodeValue)
+
+    def visitComment(self, node):
+        self.emit("comment", node.nodeValue)
+
+    def getAttributeList(self, node):
+        if not node.hasAttributes():
+            return []
+        attrList = []
+        for attrNode in node.attributes.values():
+            attrList.append((attrNode.nodeName, attrNode.nodeValue))
+        return attrList
+
+class TALCompiler(METALCompiler):
+
+    # Overriding METAL method to add attribute replacements
+    def getAttributeList(self, node):
+        attrList = METALCompiler.getAttributeList(self, node);
+        attrDict = getAttributeReplacements(node)
+        if not attrDict:
+            return attrList
+        list = []
+        for key, value in attrList:
+            if attrDict.has_key(key):
+                list.append((key, value, attrDict[key]))
+                del attrDict[key]
+            else:
+                list.append((key, value))
+        return list
+
+    # Overriding METAL method to compile TAL statements
     def compileElement(self, node):
         defines = node.getAttributeNS(ZOPE_TAL_NS, "define")
         repeat = node.getAttributeNS(ZOPE_TAL_NS, "repeat")
@@ -310,38 +353,6 @@ class TALCompiler(DOMVisitor):
         self.emit("loop", name, expr, block)
         return 1
 
-    def emitElement(self, node):
-            if not node.hasChildNodes():
-                self.emitStartEndTag(node)
-            else:
-                self.emitStartTag(node)
-                self.visitAllChildren(node)
-                self.emitEndTag(node)
-
-    def visitText(self, node):
-        self.emit("text", node.nodeValue)
-
-    def visitComment(self, node):
-        self.emit("comment", node.nodeValue)
-
-def getAttributeList(node):
-    if not node.hasAttributes():
-        return []
-    attrList = []
-    for attrNode in node.attributes.values():
-        attrList.append((attrNode.nodeName, attrNode.nodeValue))
-    attrDict = getAttributeReplacements(node)
-    if not attrDict:
-        return attrList
-    list = []
-    for key, value in attrList:
-        if attrDict.has_key(key):
-            list.append((key, value, attrDict[key]))
-            del attrDict[key]
-        else:
-            list.append((key, value))
-    return list
-
 def getAttributeReplacements(node):
     attributes = node.getAttributeNS(ZOPE_TAL_NS, "attributes")
     if not attributes: