Multi with statement

Lib/compiler/transformer.py

 """Parse tree transformation module.
 
 Transforms Python source code into an abstract syntax tree (AST)
 defined in the ast module.
 
 The simplest ways to invoke this module are via parse and parseFile.
 parse(buf) -> AST
 parseFile(path) -> AST
 """
 
@@ skipping 947 matching lines @@
                 elif node[1] == 'finally':
                     finallyNode = self.com_node(nodelist[i+2])
         try_except = TryExcept(self.com_node(nodelist[2]), clauses, elseNode,
                                lineno=nodelist[0][2])
         if finallyNode:
             return TryFinally(try_except, finallyNode, lineno=nodelist[0][2])
         else:
             return try_except
 
     def com_with(self, nodelist):
-        # with_stmt: 'with' expr [with_var] ':' suite
+        # with_stmt: 'with' with_item (',' with_item)* ':' suite
+        body = self.com_node(nodelist[-1])
+        for i in range(len(nodelist) - 3, 0, -2):
+            ret = self.com_with_item(nodelist[i], body, nodelist[0][2])
+            if i == 1:
+                return ret
+            body = ret
+
+    def com_with_item(self, nodelist, body, lineno):
+        # with_item: test ['as' expr]
+        if len(nodelist) == 4:
+            var = self.com_assign(nodelist[3], OP_ASSIGN)
+        else:
+            var = None
         expr = self.com_node(nodelist[1])
-        body = self.com_node(nodelist[-1])
-        if nodelist[2][0] == token.COLON:
-            var = None
-        else:
-            var = self.com_assign(nodelist[2][2], OP_ASSIGN)
-        return With(expr, var, body, lineno=nodelist[0][2])
-
-    def com_with_var(self, nodelist):
-        # with_var: 'as' expr
-        return self.com_node(nodelist[1])
+        return With(expr, var, body, lineno=lineno)
 
     def com_augassign_op(self, node):
         assert node[0] == symbol.augassign
         return node[1]
 
     def com_augassign(self, node):
         """Return node suitable for lvalue of augmented assignment
 
         Names, slices, and attributes are the only allowable nodes.
         """
@@ skipping 500 matching lines @@
 def debug_tree(tree):
     l = []
     for elt in tree:
         if isinstance(elt, int):
             l.append(_names.get(elt, elt))
         elif isinstance(elt, str):
             l.append(elt)
         else:
             l.append(debug_tree(elt))
     return l