DRAFT - Python 2.5 Features

This document describes the tasks of the project, the work and the expected estimation

Create a comprehensive testsuite for the actual behavior of the current project
- A comprehensive set of valid cython files must be created to cover all the current supported features of the tool, will help a lot during the transition process to
  the new parser enhancements/AutoGenParser Parser
AST Example, how to transform it

Python 2.5 missing features

Note by robertwb: Looking at the "new features" of Python 2.5 is not an accurate way to get a missing feature list. Pyrex/Cython is a subset of the 2.3 language, with extra features (type declarations, and 2.4/2/5 stuff) added on.

Importance High:

PEP 308: Conditional Expressions Implemented
- x = true_value if condition else false_value
PEP 341: Unified try/except/finally Implemented
```
       try:
           block-1 ...
         except Exception1:
               handler-1 ...
               except Exception2:
                   handler-2 ...
                   else:
                       else-block
                       finally:
                           final-block  
```
PEP 342: New Generator Features def counter (maximum):
- i = 0
  while i < maximum:
  - yield i i += 1
PEP 343 With Statement
- Support for contextManager ?
PEP 353: Using ssize_t as the index type Implemented
- I think this affect Cython in some way
PEP 357: The 'index' method Implemented. Could be optimized.
- Is this supported? can be optimized?

Importance Low:

PEP 328: Absolute and Relative Imports
- from future import absolute_import
PEP 352: Exceptions as New-Style Classes Python C Api Code:
- from http://docs.python.org/whatsnew/ports.html support for: Call PySet_New() and PyFrozenSet_New() to create a new set, PySet_Add() and PySet_Discard() to add and remove elements, and PySet_Contains and PySet_Size to examine the set's state. Two new macros can be used to indicate C functions that are local to the current file so that a faster calling convention can be used. Py_LOCAL(type) declares the function as returning a value of the specified type and uses a fast-calling qualifier. Py_LOCAL_INLINE(type) does the same thing and also requests the function be inlined. If PY_LOCAL_AGGRESSIVE is defined before python.h is included, a set of more aggressive optimizations are enabled for the module; you should benchmark the results to find out if these optimizations actually make the code faster.
  TODO: is PyRange_New() used by cython ?
Python Modules:
- missing(key) ? The list of base classes in a class definition can now be empty class C():
  - pass

Improve:

PEP 309: Partial Function Application
- import functools def log (message, subsystem): "Write the contents of 'message' to the specified subsystem." print '%s: %s' % (subsystem, message)
  - .. server_log = functools.partial(log, subsystem='server') server_log('Unable to open socket') these works but could be optimized to create the real partial function: steps: to be done: NOT YET DEFINED
- with - from import *

Backup: Profiling & Optimization: In the luckily event that all the above will be implement in time

I will do a complete profiling of the Cython and of the Generated Source. some ideas are: use gprof perfect hash for fixed dictionaries?

Features to support in python 3k: