Implement __repr__ on Nodes (Issue #226) (#227)

* Implement __repr__ on Nodes.

3 files changed, 107 insertions, 2 deletions

diff --git a/pycparser/_ast_gen.py b/pycparser/_ast_gen.py
index 526d1ec..4dab963 100644
--- a/pycparser/_ast_gen.py
+++ b/pycparser/_ast_gen.py
@@ -63,6 +63,7 @@ class NodeCfg(object):
         contents: a list of contents - attributes and child nodes
         See comment at the top of the configuration file for details.
     """
+
     def __init__(self, name, contents):
         self.name = name
         self.all_entries = []
@@ -85,6 +86,7 @@ class NodeCfg(object):
         src = self._gen_init()
         src += '\n' + self._gen_children()
         src += '\n' + self._gen_iter()
+
         src += '\n' + self._gen_attr_names()
         return src
 
@@ -187,11 +189,38 @@ r'''#-----------------------------------------------------------------
 _PROLOGUE_CODE = r'''
 import sys
 
+def _repr(obj):
+    """
+    Get the representation of an object, with dedicated pprint-like format for lists.
+    """
+    if isinstance(obj, list):
+        return '[' + (',\n '.join((_repr(e).replace('\n', '\n ') for e in obj))) + '\n]'
+    else:
+        return repr(obj) 
 
 class Node(object):
     __slots__ = ()
     """ Abstract base class for AST nodes.
     """
+    def __repr__(self):
+        """ Generates a python representation of the current node
+        """
+        result = self.__class__.__name__ + '('
+        
+        indent = ''
+        separator = ''
+        for name in self.__slots__[:-2]:
+            result += separator
+            result += indent
+            result += name + '=' + (_repr(getattr(self, name)).replace('\n', '\n  ' + (' ' * (len(name) + len(self.__class__.__name__)))))
+            
+            separator = ','
+            indent = '\n ' + (' ' * len(self.__class__.__name__))
+        
+        result += indent + ')'
+        
+        return result
+
     def children(self):
         """ A sequence of all children that are Nodes
         """
diff --git a/pycparser/c_ast.py b/pycparser/c_ast.py
index 99cd6a4..219f07b 100644
--- a/pycparser/c_ast.py
+++ b/pycparser/c_ast.py
@@ -18,11 +18,38 @@
 
 import sys
 
+def _repr(obj):
+    """
+    Get the representation of an object, with dedicated pprint-like format for lists and tuples.
+    """
+    if isinstance(obj, list):
+        return '[' + (',\n '.join((_repr(e).replace('\n', '\n ') for e in obj))) + '\n]'
+    else:
+        return repr(obj) 
 
 class Node(object):
     __slots__ = ()
     """ Abstract base class for AST nodes.
     """
+    def __repr__(self):
+        """ Generates a python representation of the current node
+        """
+        result = self.__class__.__name__ + '('
+        
+        indent = ''
+        separator = ''
+        for name in self.__slots__[:-2]:
+            result += separator
+            result += indent
+            result += name + '=' + (_repr(getattr(self, name)).replace('\n', '\n  ' + (' ' * (len(name) + len(self.__class__.__name__)))))
+            
+            separator = ','
+            indent = '\n ' + (' ' * len(self.__class__.__name__))
+        
+        result += indent + ')'
+        
+        return result
+
     def children(self):
         """ A sequence of all children that are Nodes
         """
diff --git a/tests/test_c_ast.py b/tests/test_c_ast.py
index bfe301a..8e95d55 100644
--- a/tests/test_c_ast.py
+++ b/tests/test_c_ast.py
@@ -38,7 +38,6 @@ class Test_c_ast(unittest.TestCase):
         self.assertEqual(weakref.getweakrefcount(coord), 1)
 
 
-
 class TestNodeVisitor(unittest.TestCase):
     class ConstantVisitor(c_ast.NodeVisitor):
         def __init__(self):
@@ -94,7 +93,57 @@ class TestNodeVisitor(unittest.TestCase):
         cv.visit(comp)
 
         self.assertEqual(cv.values,
-            ['5.6', 't', '5.6', 't', 't', '5.6', 't'])
+                         ['5.6', 't', '5.6', 't', 't', '5.6', 't'])
+
+    def test_repr(self):
+        c1 = c_ast.Constant(type='float', value='5.6')
+        c2 = c_ast.Constant(type='char', value='t')
+
+        b1 = c_ast.BinaryOp(
+            op='+',
+            left=c1,
+            right=c2)
+
+        b2 = c_ast.BinaryOp(
+            op='-',
+            left=b1,
+            right=c2)
+
+        comp = c_ast.Compound(
+            block_items=[b1, b2, c1, c2])
+
+        expected = ("Compound(block_items=[BinaryOp(op='+',\n"
+                    "                               left=Constant(type='float',\n"
+                    "                                             value='5.6'\n"
+                    "                                             ),\n"
+                    "                               right=Constant(type='char',\n"
+                    "                                              value='t'\n"
+                    "                                              )\n"
+                    "                               ),\n"
+                    "                      BinaryOp(op='-',\n"
+                    "                               left=BinaryOp(op='+',\n"
+                    "                                             left=Constant(type='float',\n"
+                    "                                                           value='5.6'\n"
+                    "                                                           ),\n"
+                    "                                             right=Constant(type='char',\n"
+                    "                                                            value='t'\n"
+                    "                                                            )\n"
+                    "                                             ),\n"
+                    "                               right=Constant(type='char',\n"
+                    "                                              value='t'\n"
+                    "                                              )\n"
+                    "                               ),\n"
+                    "                      Constant(type='float',\n"
+                    "                               value='5.6'\n"
+                    "                               ),\n"
+                    "                      Constant(type='char',\n"
+                    "                               value='t'\n"
+                    "                               )\n"
+                    "                     ]\n"
+                    "         )")
+
+        self.assertEqual(repr(comp),
+                         expected)
 
 
 if __name__ == '__main__':