Merged revisions 62004 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r62004 | georg.brandl | 2008-03-28 13:11:56 +0100 (Fr, 28 Mär 2008) | 4 lines

  Patch #1810 by Thomas Lee, reviewed by myself:
  allow compiling Python AST objects into code objects
  in compile().
........

1 files changed, 13 insertions, 10 deletions

diff --git a/Doc/library/_ast.rst b/Doc/library/_ast.rst
index 9f56156..518798e 100644
--- a/Doc/library/_ast.rst
+++ b/Doc/library/_ast.rst
@@ -10,16 +10,16 @@ Abstract Syntax Trees
 
 
 The ``_ast`` module helps Python applications to process trees of the Python
-abstract syntax grammar. The Python compiler currently provides read-only access
-to such trees, meaning that applications can only create a tree for a given
-piece of Python source code; generating :term:`bytecode` from a (potentially modified)
-tree is not supported. The abstract syntax itself might change with each Python
-release; this module helps to find out programmatically what the current grammar
-looks like.
+abstract syntax grammar.  The abstract syntax itself might change with each
+Python release; this module helps to find out programmatically what the current
+grammar looks like.
 
-An abstract syntax tree can be generated by passing ``_ast.PyCF_ONLY_AST`` as a
-flag to the :func:`compile` builtin function. The result will be a tree of
-objects whose classes all inherit from ``_ast.AST``.
+An abstract syntax tree can be generated by passing :data:`_ast.PyCF_ONLY_AST`
+as a flag to the :func:`compile` builtin function. The result will be a tree of
+objects whose classes all inherit from :class:`_ast.AST`.
+
+A modified abstract syntax tree can be compiled into a Python code object using
+the built-in :func:`compile` function.
 
 The actual classes are derived from the ``Parser/Python.asdl`` file, which is
 reproduced below. There is one class defined for each left-hand side symbol in
@@ -39,12 +39,15 @@ attribute ``left`` of type ``_ast.expr``.   Instances of ``_ast.expr`` and
 ``_ast.stmt`` subclasses also have lineno and col_offset attributes.  The lineno
 is the line number of source text (1 indexed so the first line is line 1) and
 the col_offset is the utf8 byte offset of the first token that generated the
-node.  The utf8 offset is recorded because the parser uses utf8  internally.
+node.  The utf8 offset is recorded because the parser uses utf8 internally.
 
 If these attributes are marked as optional in the grammar (using a question
 mark), the value might be ``None``. If the attributes can have zero-or-more
 values (marked with an asterisk), the values are represented as Python lists.
 
+The constructors of all ``_ast`` classes don't take arguments; instead, if you
+create instances, you must assign the required attributes separately.
+
 
 Abstract Grammar
 ----------------