BUGFIX: iter_trees() wasn't consistent with a recursive order (Issue #47)

lark/tree.py

@@ -67,17 +67,26 @@ class Tree(object):
                     yield c
 
     def iter_subtrees(self):
+        # TODO: Re-write as a more efficient version
+
         visited = set()
         q = [self]
 
+        l = []
         while q:
             subtree = q.pop()
+            l.append( subtree )
             if id(subtree) in visited:
                 continue    # already been here from another branch
             visited.add(id(subtree))
-            yield subtree
             q += [c for c in subtree.children if isinstance(c, Tree)]
 
+        seen = set()
+        for x in reversed(l):
+            if id(x) not in seen:
+                yield x
+                seen.add(id(x))
+
 
     def __deepcopy__(self, memo):
         return type(self)(self.data, deepcopy(self.children, memo))
@@ -147,7 +156,7 @@ class Visitor_NoRecurse(Visitor):
     def visit(self, tree):
         subtrees = list(tree.iter_subtrees())
 
-        for subtree in reversed(subtrees):
+        for subtree in (subtrees):
             getattr(self, subtree.data, self.__default__)(subtree)
         return tree
 
@@ -165,7 +174,7 @@ class Transformer_NoRecurse(Transformer):
             else:
                 return f(t)
 
-        for subtree in reversed(subtrees):
+        for subtree in (subtrees):
             subtree.children = [_t(c) if isinstance(c, Tree) else c for c in subtree.children]
 
         return _t(tree)