Primitive for 'comment' block and Comment AST class to make it exportable

  - Primitive object for the 'comment' block using the new Primitive.comment
    function.
  - Special handling of Primitives using Primitive.comment during export.
  - New util.ast_extensions module containing extensions to the built-in `ast`
    module. Currently it contains the Comment class for inline comments.
  - New visit_Comment method in util.codegen to serialize inline comments.

2 files changed, 46 insertions, 0 deletions

diff --git a/util/ast_extensions.py b/util/ast_extensions.py
new file mode 100644
index 0000000..ac29421
--- /dev/null
+++ b/util/ast_extensions.py
@@ -0,0 +1,41 @@
+#Copyright (c) 2013 Marion Zepf
+
+#Permission is hereby granted, free of charge, to any person obtaining a copy
+#of this software and associated documentation files (the "Software"), to deal
+#in the Software without restriction, including without limitation the rights
+#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+#copies of the Software, and to permit persons to whom the Software is
+#furnished to do so, subject to the following conditions:
+
+#The above copyright notice and this permission notice shall be included in
+#all copies or substantial portions of the Software.
+
+#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+#THE SOFTWARE.
+
+
+""" Extend the `ast` module to include comments """
+
+import ast
+
+
+class Comment(ast.stmt):
+    """ An inline comment, starting with a hashtag (#).
+    Extends the Python abstract grammar by the following:
+    stmt = Comment(string text) | ... """
+
+    _fields = ('text')
+
+    def __init__(self, text="", lineno=1, col_offset=0):
+        """ text -- the textual content of the comment, i.e. everything
+            directly following the hashtag until the next newline """
+        self.text = text
+        self.lineno = lineno
+        self.col_offset = col_offset
+
+
diff --git a/util/codegen.py b/util/codegen.py
index ead6dd0..1bcc42f 100644
--- a/util/codegen.py
+++ b/util/codegen.py
@@ -35,6 +35,7 @@
     Modified by Marion Zepf.
 """
 from ast import *
+from ast_extensions import Comment
 
 
 def to_source(node, indent_with=' ' * 4, add_line_information=False):
@@ -356,6 +357,10 @@ class SourceGenerator(NodeVisitor):
                 self.write(', ')
                 self.visit(node.tback)
 
+    def visit_Comment(self, node):
+        self.newline(node)
+        self.write('#' + str(node.text))
+
     # Expressions
 
     def visit_Attribute(self, node):