Beautify Node.show() for parse tree printing

pycparser/_ast_gen.py

@@ -224,7 +224,7 @@ def children(self):
         """
         pass
 
-    def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showcoord=False, _my_node_name=None):
+    def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showcoord=False, _my_node_name=None, indent='', islast = True):
         """ Pretty print the Node and all its attributes and
             children (recursively) to a buffer.
 
@@ -245,8 +245,16 @@ def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showc
             showcoord:
                 Do you want the coordinates of each Node to be
                 displayed.
+
+            indent:
+                Spaces and vertical lines to be displayed in front of node.
+
+            islast:
+                Denotes if node is final element in its tree.
         """
-        lead = ' ' * offset
+        marker = "└─" if islast else "├─"
+        lead = ' ' * offset + indent + marker
+
         if nodenames and _my_node_name is not None:
             buf.write(lead + self.__class__.__name__+ ' <' + _my_node_name + '>: ')
         else:
@@ -265,14 +273,18 @@ def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showc
             buf.write(' (at %s)' % self.coord)
         buf.write('\n')
 
-        for (child_name, child) in self.children():
+        indent += "  " if islast else "│ "
+
+        for idx, (child_name, child) in enumerate(self.children()):
             child.show(
                 buf,
-                offset=offset + 2,
+                offset=offset,
                 attrnames=attrnames,
                 nodenames=nodenames,
                 showcoord=showcoord,
-                _my_node_name=child_name)
+                _my_node_name=child_name,
+                indent=indent,
+                islast=(idx == len(self.children())-1))
 
 
 class NodeVisitor(object):

pycparser/_build_tables.py

@@ -20,7 +20,7 @@
 # Generate c_ast.py
 from _ast_gen import ASTCodeGenerator
 ast_gen = ASTCodeGenerator('_c_ast.cfg')
-ast_gen.generate(open('c_ast.py', 'w'))
+ast_gen.generate(open('c_ast.py', 'w', encoding='UTF-8')))
 
 from pycparser import c_parser
 

pycparser/c_ast.py

@@ -55,7 +55,7 @@ def children(self):
         """
         pass
 
-    def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showcoord=False, _my_node_name=None):
+    def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showcoord=False, _my_node_name=None, indent='', islast = True):
         """ Pretty print the Node and all its attributes and
             children (recursively) to a buffer.
 
@@ -76,8 +76,16 @@ def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showc
             showcoord:
                 Do you want the coordinates of each Node to be
                 displayed.
+
+            indent:
+                Spaces and vertical lines to be displayed in front of node.
+
+            islast:
+                Denotes if node is final element in its tree.
         """
-        lead = ' ' * offset
+        marker = "└─" if islast else "├─"
+        lead = ' ' * offset + indent + marker
+
         if nodenames and _my_node_name is not None:
             buf.write(lead + self.__class__.__name__+ ' <' + _my_node_name + '>: ')
         else:
@@ -96,14 +104,18 @@ def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showc
             buf.write(' (at %s)' % self.coord)
         buf.write('\n')
 
-        for (child_name, child) in self.children():
+        indent += "  " if islast else "│ "
+
+        for idx, (child_name, child) in enumerate(self.children()):
             child.show(
                 buf,
-                offset=offset + 2,
+                offset=offset,
                 attrnames=attrnames,
                 nodenames=nodenames,
                 showcoord=showcoord,
-                _my_node_name=child_name)
+                _my_node_name=child_name,
+                indent=indent,
+                islast=(idx == len(self.children())-1))
 
 
 class NodeVisitor(object):