diff --git a/pycparserext/ext_c_parser.py b/pycparserext/ext_c_parser.py
index b59d98e..7611ce1 100644
--- a/pycparserext/ext_c_parser.py
+++ b/pycparserext/ext_c_parser.py
@@ -169,6 +169,12 @@ class FuncDeclExt(c_ast.Node):
             nodelist.append(("asm", self.asm))
         return tuple(nodelist)
 
+    def __iter__(self):
+        if self.args is not None:
+            yield self.args
+        if self.type is not None:
+            yield self.type
+
     attr_names = ()
 
 # }}}

diff --git a/test/test_pycparserext.py b/test/test_pycparserext.py
index e93eb78..d6e9666 100644
--- a/test/test_pycparserext.py
+++ b/test/test_pycparserext.py
@@ -375,6 +375,24 @@ def test_double_pointer():
     assert gen.visit(ast).find("func_with_p2pp(const char *, Error **)") != -1
 
 
+def test_node_visitor():
+    from pycparser.c_ast import NodeVisitor
+
+    class FuncDeclVisitor(NodeVisitor):
+        def visit_FuncDecl(self, node):
+            node.show()
+
+    src = """
+    void func1();
+    int func2(int param1);
+    """
+    import pycparserext.ext_c_parser as ext_c_parser
+
+    parser = ext_c_parser.GnuCParser()
+    ast = parser.parse(src)
+    FuncDeclVisitor().visit(ast)
+
+
 if __name__ == "__main__":
     import sys
     if len(sys.argv) > 1:

Cannot traverse nodes using NodeVisitor, FuncDeclExt is not iterable
Using `GnuCParser()` and subclassing `c_ast.NodeVisitor`, I cannot traverse the nodes as in the FuncDefs example in https://github.com/eliben/pycparser/blob/master/examples/func_defs.py

It results in the following error:
```
Traceback (most recent call last):
  [...]
  File "main_script.py", line 77, in verify
    FuncDefVisitor().visit(self.ast)
  File "/path/venv/lib/python3.6/site-packages/pycparser/c_ast.py", line 158, in visit
    return visitor(node)
  File "/path/venv/lib/python3.6/site-packages/pycparser/c_ast.py", line 165, in generic_visit
    self.visit(c)
  File "/path/venv/lib/python3.6/site-packages/pycparser/c_ast.py", line 158, in visit
    return visitor(node)
  File "/path/venv/lib/python3.6/site-packages/pycparser/c_ast.py", line 165, in generic_visit
    self.visit(c)
  File "/path/venv/lib/python3.6/site-packages/pycparser/c_ast.py", line 158, in visit
    return visitor(node)
  File "/path/venv/lib/python3.6/site-packages/pycparser/c_ast.py", line 164, in generic_visit
    for c in node:
TypeError: 'FuncDeclExt' object is not iterable
```
test/test_pycparserext.py::test_node_visitor
test/test_pycparserext.py::test_asm_volatile_1 test/test_pycparserext.py::test_asm_volatile_2 test/test_pycparserext.py::test_asm_volatile_3 test/test_pycparserext.py::test_funky_header_code test/test_pycparserext.py::test_funky_header_code_2 test/test_pycparserext.py::test_funky_header_code_3 test/test_pycparserext.py::test_funky_header_code_4 test/test_pycparserext.py::test_funky_header_code_5 test/test_pycparserext.py::test_opencl[int] test/test_pycparserext.py::test_opencl[uint] test/test_pycparserext.py::test_array_attributes test/test_pycparserext.py::test_func_decl_attribute test/test_pycparserext.py::test_func_ret_ptr_decl_attribute test/test_pycparserext.py::test_array_ptr_decl_attribute test/test_pycparserext.py::test_gnu_statement_expression test/test_pycparserext.py::test_empty_gnu_statement_expression test/test_pycparserext.py::test_empty_struct_declaration test/test_pycparserext.py::test_nesty_c_declarator test/test_pycparserext.py::test_const_ptr_func_arg test/test_pycparserext.py::test_pointer_reproduction test/test_pycparserext.py::test_no_added_attr test/test_pycparserext.py::test_double_pointer