py3k_extension 20081023

extension module backporting opcodes from python3k

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REVISION DATE: 20081023

AUTHOR: kai zhu - [e-mail]

HOMEPAGE: http://www-rcf.usc.edu/~kaizhu/work/py3to2/old/extension

ABSTRACT:
this is a minimal, standalone, proof-of-concept extension module for
python2.6, emulating limited python3.0 syntax behavior, thru usage of some
backported opcodes from python3.0. it is intended as a curiousity for hackers.

this module is derived from py3to2. the difference is that this is a
standalone module which requires no patching of python2.6 to work.
the tradeoff is that it is not 100& py3k language compliant, as py3to2
nearly is (see LIMITATIONS).

i wrote this module b/c i kno many ppl r loathe to patch their python-2.6 src
in order to run py3to2. this is a compromise, but plz note it has severe
limitations.

MECHANISM:
1. upon init, py3k_extension starts up a py3k server w/ pipe io.

2. -> received via pipe io from py3k_extension, the py3k server 1st
natively compiles the src code into a py3k codeobj, then converts it
to py2x format w/ the addition of the backported opcodes.

3. <- the serialized py2x codeobj is piped back to py3k_extension,
which unserializes it & eval/exec it as normal.

in theory, this mechanism should transparently implement any bytecode-level py3k
language feature. performance and robustness should b minimally impacted, since
the compiled code is directly run as native 2.x++ bytecode.

BACKWARD COMPATIBILITY:
since this is a standalone extension module which doesn't modify python's
source code in any way, there shouldn't b any backward compatibility issues as
long as the module is not imported

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LIMITATIONS:
as a minimal extension module, this module DOES NOT SUPPORT CLASSES,
IMPORTING PY3K MODULES, OR FUNCTION KEYWORD-ONLY ARGUMENTS.
any py3k code containing classes will not work.

PY3K FEATURES TESTED TO WORK:
pep3104 Access to Names in Outer Scopes
pep3112 Bytes literals in Python 3000
pep3113 Removal of Tuple Parameter Unpacking
pep3132 Extended Iterable Unpacking

REQUIREMENTS:
* linux / unix (windows has io problems w/ py3k server)

BUILD/INSTALL: python setup.py build install

USAGE:
this module provides 3 wrapper functions similar to what's in python-3.0's
builtins:
- py3k_compile(code, filename, mode, flags, dont_inherit)
- py3k_eval(code, globals = None, locals = None)
- py3k_exec(code, globals = None, locals = None)

EXAMPLE:
Python 2.6 (r26:66714, Oct 19 2008, 02:49:13)
[GCC 3.4.6 20060404 (Red Hat 3.4.6-10)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import py3k_extension
created read/write pipes: (4, 5)
py3k server starting with pipes in/out/err: 7 5 -2
py3k server: Python 3.0rc1 (r30rc1:66499, Oct 15 2008, 15:43:09)
py3k server: [GCC 3.4.6 20060404 (Red Hat 3.4.6-10)] on linux2
py3k server: Type "help", "copyright", "credits" or "license" for more
information.
py3k server: >>> ''
>>>
>>> py3k_exec( "a, *b = 1,2,3" ) # pep3132 Extended Iterable Unpacking
>>> print a, b
1 [2, 3]
>>>
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CHANGELOG:
20081023
created a standalone extension module w/ limited capabilities
20081019
ported to python-2.6
consolidate & simplify patches to 1 file: ceval.c
created extension module builtins_py3k
revamped import hook again
removed unicode support & restrict source code to ascii-only
20080727
revampled import hook
20080911
consolidate patches to 2 files: bltinmodule.c & ceval.c
20080828
add kwonlyargcount 'attr' to codeobj
add __annotations__ & __kwdefaults__ attr to funcobj
add __pseudomethod__ feature to baseobj
20080819
pure python import hook - removed magic comment & use magic path instead
revamped str & bytes handling
revamped py3k .pyc file handling
20080802
pep3135 New Super
20080717
pep3107 Function Annotations
pep3120 Using UTF-8 as the default source encoding
pep3131 Supporting Non-ASCII Identifiers
20080713
import / reload works transparently on py3k scripts using a magic comment
added pep3102 Keyword-Only Arguments
20080709 added a py3k preparser
20080702
rewrote py3k server's pipe io. implemented partial bytearray & bytes class.
wrote a few simple tests
20080630
__build_class__ function to bltmodule.c. tested class decorators to b working.
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