withhacks 0.1.1

withhacks: building blocks for with-statement-related hackery

This module is a collection of useful building-blocks for hacking the Python “with” statement. It combines ideas from several neat with-statement hacks I found around the internet into a suite of re-usable components:

• http://www.mechanicalcat.net/richard/log/Python/Something_I_m_working_on.3

• http://billmill.org/multi_line_lambdas.html

• http://code.google.com/p/ouspg/wiki/AnonymousBlocksInPython

By subclassing the appropriate context managers from this module, you can easily do things such as:

• skip execution of the code inside the with-statement

• set local variables in the frame executing the with-statement

• capture the bytecode from inside the with-statement

• capture local variables defined inside the with-statement

Building on these basic tools, this module also provides some useful prebuilt hacks:

xargs:

call a function with additional arguments defined in the body of the with-statement

xkwargs:

call a function with additional keyword arguments defined in the body of the with-statement

namespace:

direct all variable accesses and assignments to the attributes of a given object (like “with” in JavaScript or VB)

keyspace:

direct all variable accesses and assignments to the keys of of a given object (like namespace() but for dicts)

WithHacks makes extensive use of Noam Raphael’s fantastic “byteplay” module; since the official byteplay distribution doesn’t support Python 2.6, a local version with appropriate patches is included in this module.