otus-cpython-patches

Warning: The sources and examples in the repository are only compatible with Python 2.7

Description

This repository contains the following three patches that add new features to the Python language:

1. new_opcode.patch This patch adds the new LOAD_OTUS opcode (Python bytecode instruction, see https://docs.python.org/2.7/library/dis.html). LOAD_OTUS opcode combines existing LOAD_FAST and LOAD_CONST opcodes as follows:

   LOAD_OTUS c
   

   is equivalent to:

   LOAD_FAST 0
   LOAD_CONST c
   

   where c is the integer argument.

   Since the above combination of LOAD_FAST and LOAD_CONST is relatively common, this change is intended to speed up bytecode execution and make dis.dis() output a little more compact.

2. until.patch adds an until loop operator to the language, which is opposite to the existing while operator. Usage example:

   num = 3
   until num == 0:
       print num
       num -= 1

   Output of the above code:

   3
   2
   1
   

3. inc.patch adds ++ (increment) and -- (decrement) operators to the language:

   test = 1
   test--
   print test
   test++
   print test

   Output of the above code:

   0
   1
   

Usage

*.patch files can be applied to the cpython sources using git (checkout to the 2.7 tag is required):

git clone https://github.com/python/cpython.git 
cd cpython 
git checkout 2.7 
git apply patchname.patch

To build python:

./configure --with-pydebug --prefix=/tmp/python 
make