Patch #1810 by Thomas Lee, reviewed by myself:
allow compiling Python AST objects into code objects
in compile().
diff --git a/Doc/library/_ast.rst b/Doc/library/_ast.rst
index 9383591..e9f4ad4 100644
--- a/Doc/library/_ast.rst
+++ b/Doc/library/_ast.rst
@@ -12,16 +12,16 @@
.. versionadded:: 2.5
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
@@ -41,12 +41,15 @@
``_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
----------------
diff --git a/Doc/library/compiler.rst b/Doc/library/compiler.rst
index 5f5ed44..d744bc0 100644
--- a/Doc/library/compiler.rst
+++ b/Doc/library/compiler.rst
@@ -28,12 +28,6 @@
This chapter explains how the various components of the :mod:`compiler` package
work. It blends reference material with a tutorial.
-The following modules are part of the :mod:`compiler` package:
-
-.. toctree::
-
- _ast.rst
-
The basic interface
===================
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index e966495..b26655e 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -190,21 +190,27 @@
.. function:: compile(source, filename, mode[, flags[, dont_inherit]])
- Compile the *source* into a code object. Code objects can be executed by an
- :keyword:`exec` statement or evaluated by a call to :func:`eval`. The
- *filename* argument should give the file from which the code was read; pass some
- recognizable value if it wasn't read from a file (``'<string>'`` is commonly
- used). The *mode* argument specifies what kind of code must be compiled; it can
- be ``'exec'`` if *source* consists of a sequence of statements, ``'eval'`` if it
- consists of a single expression, or ``'single'`` if it consists of a single
- interactive statement (in the latter case, expression statements that evaluate
- to something else than ``None`` will be printed).
+ Compile the *source* into a code or AST object. Code objects can be executed
+ by an :keyword:`exec` statement or evaluated by a call to :func:`eval`.
+ *source* can either be a string or an AST object. Refer to the :mod:`_ast`
+ module documentation for information on how to compile into and from AST
+ objects.
- When compiling multi-line statements, two caveats apply: line endings must be
- represented by a single newline character (``'\n'``), and the input must be
- terminated by at least one newline character. If line endings are represented
- by ``'\r\n'``, use the string :meth:`replace` method to change them into
- ``'\n'``.
+ When compiling a string with multi-line statements, two caveats apply: line
+ endings must be represented by a single newline character (``'\n'``), and the
+ input must be terminated by at least one newline character. If line endings
+ are represented by ``'\r\n'``, use the string :meth:`replace` method to
+ change them into ``'\n'``.
+
+ The *filename* argument should give the file from which the code was read;
+ pass some recognizable value if it wasn't read from a file (``'<string>'`` is
+ commonly used).
+
+ The *mode* argument specifies what kind of code must be compiled; it can be
+ ``'exec'`` if *source* consists of a sequence of statements, ``'eval'`` if it
+ consists of a single expression, or ``'single'`` if it consists of a single
+ interactive statement (in the latter case, expression statements that
+ evaluate to something else than ``None`` will be printed).
The optional arguments *flags* and *dont_inherit* (which are new in Python 2.2)
control which future statements (see :pep:`236`) affect the compilation of
@@ -224,6 +230,9 @@
This function raises :exc:`SyntaxError` if the compiled source is invalid,
and :exc:`TypeError` if the source contains null bytes.
+ .. versionadded:: 2.6
+ Support for compiling AST objects.
+
.. function:: complex([real[, imag]])
diff --git a/Doc/library/language.rst b/Doc/library/language.rst
index d405a4b..7d6af7d 100644
--- a/Doc/library/language.rst
+++ b/Doc/library/language.rst
@@ -15,6 +15,7 @@
.. toctree::
parser.rst
+ _ast.rst
symbol.rst
token.rst
keyword.rst