backport python 3.0 language functionality to python 2.5 by adding 8 opcodes to ceval.c

[54f903ae-9f23-46ad-88dd-da1ca57b7cf8]

BPO	3225
Nosy	@loewis
Files	ceval.c: Python 2.5.2 ceval.c patched by adding 8 new opcodes to PyEval_EvalFrameEx

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields: ```python assignee = None closed_at = created_at = labels = ['type-feature', 'expert-2to3'] title = 'backport python 3.0 language functionality to python 2.5 by adding 8 opcodes to ceval.c' updated_at = user = 'https://bugs.python.org/kaizhu' ``` bugs.python.org fields: ```python activity = actor = 'loewis' assignee = 'collinwinter' closed = True closed_date = closer = 'loewis' components = ['2to3 (2.x to 3.x conversion tool)'] creation = creator = 'kaizhu' dependencies = [] files = ['10758'] hgrepos = [] issue_num = 3225 keywords = [] message_count = 2.0 messages = ['68873', '68874'] nosy_count = 3.0 nosy_names = ['loewis', 'collinwinter', 'kaizhu'] pr_nums = [] priority = 'normal' resolution = 'rejected' stage = None status = 'closed' superseder = None type = 'enhancement' url = 'https://bugs.python.org/issue3225' versions = ['Python 2.5'] ```

[54f903ae-9f23-46ad-88dd-da1ca57b7cf8]

this patch touches only Python/ceval.c.

1. the only existing thing it modifies is PyEval_EvalFrameEx (adds 8 extra cases for the new 3.0 opcodes, doesn't mess w/ any of the existing ones, or anything else as a matter of fact)

2. that, plus it defines (the new opcodes)
#define SET_ADD 17            
#define STORE_MAP 54          
#define STORE_LOCALS 69       
#define LOAD_BUILD_CLASS 34   
#define MAKE_BYTES 35         
#define POP_EXCEPT 36         
#define UNPACK_EX 94          
#define BUILD_SET 109         
and some backported vars & helper functions

only 2 contiguous areas of ceval.c is patched (1. & 2. - areas are delimited by the comments '// py3k')

this simple patch seems sufficient in theory to allow the interpreter to natively execute most of 3.0's language syntax (nonlocal, print, extended unpacking... have been tested to work) *the one exception being PEP-3102 - keyword-only arguments

i wrote 2 small scripts which gives an interactive function 'compilepy3k' similar to \_builtin__.compile except it works only for 3.0 syntax. it doesn't actually compile, but rather cheats by querying it to a python 3.0 server via pipe io.

here is an interactive demonstration of my script:

example demonstrating PEP-3132 extended unpacking syntax: a,b,*c = 1,2,3,4

Python 2.5.2 (r252:60911, Jun 27 2008, 21:19:51) [GCC 3.4.6 20060404 (Red Hat 3.4.6-9)] on linux2 Type "help", "copyright", "credits" or "license" for more information.

>>> import py3to2
py3to2 server restarting with io: (4, 5)
py3to2 server: Python 3.0b1 (r30b1:64395, Jun 24 2008, 21:53:55)
py3to2 server: [GCC 3.4.6 20060404 (Red Hat 3.4.6-9)] on linux2
py3to2 server: Type "help", "copyright", "credits" or "license" for more
information.
py3to2 server: 

>>> src = "a,b,*c = 1,2,3,4"
>>> codeobject = py3to2.compile_py3k(src,"","exec")
  1           0 LOAD_CONST               5 ((1, 2, 3, 4))
              3 UNPACK_EX_py3k           2
              6 STORE_NAME               0 (a)
              9 STORE_NAME               1 (b)
             12 STORE_NAME               2 (c)
             15 LOAD_CONST               4 (None)
             18 RETURN_VALUE

>>> exec(codeobject); print "a=%s, b=%s, c=%s"%(a,b,c)
a=1, b=2, c=[3, 4]
>>>

u can go c http://pypi.python.org/pypi?name=py3to2&version=20080628&:action=display for more info

anyway, i think it would b a great boost for python 3.0 (which i think is very cool) if developers can test/develop it under the robust 2.5 environment. this patch plus some scripts could go a long way in making that happen

[61337411-43fc-4a9c-b8d5-4060aede66d0]

Sorry, but adding new feature into the 2.5.3 release (or any later 2.5 release) is unacceptable; the feature list of 2.5 was frozen in 2006 (when the first beta release of 2.5 was made). Thus, I'm rejecting the patch.