relax SVN archive

Changed all the default can_be_none keywords to False.

This is so you have to explicitly say if None is allowed, rather than the other way around.

Added 2 more arg checking functions, is_float() and is_num_tuple().

Added a new error class, RelaxTupleNumError.

Removed the num_types module as this is redundant with the new check module.

Simplified the sequence user function class by using the check and base_class modules.

Created a base class for the user function classes.

This defines the __init__() method for creating the relax help string.

Updated the 2to3 checklist for the idioms.

Added a module containing functions for checking user function args.

So far this includes:
check.is_bool()
check.is_int()
check.is_str()

The Python 2.x idioms have been removed.

This was done with the python 2.x to 3.x script with the commands:
2to3 -w -f exec relax .

The change is in preparation for Python 3.0, and relax still works with Python versions 2.4, 2.5,
and 2.6.

The changes include:
1) The call to type() has been replaced with isinstance().
2) "while 1" has been replaced with "while True".
3) list sort methods x.sort() have been replaced with a call to sorted(x).

Booleans are instances of int, so the user function argument unit tests will be a massive mess!

Added a text file documenting the changes in preparation for Python 3.x.