[PEAK] AmbiguousMethod using PEAK-Rules

[Scott Graham]

Hi, I was just trying out PEAK-Rules, which I installed by doing:

easy_install svn://svn.eby-sarna.com/svnroot/BytecodeAssembler
easy_install svn://svn.eby-sarna.com/svnroot/PEAK-Rules

Consider the following code: (taken from
http://www.eby-sarna.com/pipermail/peak/2008-January/002825.html)

------------
from peak.rules import *

@abstract
def f(a,b):
     """A function"""

@when(f, (int, str))
def f_int_str(a, b):
    print "f_int_str: %s %s" % (a, b)

@when(f, (str, int))
def f_str_int(a, b):
    print "f_str_int: %s %s" % (a, b)

@when(f, "isinstance(a,str) and isinstance(b, int) and b==42")
def f_str_42(a, b):
    print "f_str_42: %s %s" % (a, b)

f(4, "stuff")
f("stuff", 4)
f("stuff", 42)
------------

I was hoping all 3 functions would be called in turn, but I get:

f_int_str: 4 stuff
f_str_int: stuff 4
Traceback (most recent call last):
  File "x.py", line 21, in <module>
    f("stuff", 42)
  File "<generated code>", line 0, in f
  File "build/bdist.linux-i686/egg/peak/rules/core.py", line 214, in __call__
peak.rules.core.AmbiguousMethods: ([Method(<function f_str_int at
0xb7b0080c>, Signature([Test(IsInstance(Local('a')), Class(<type
'str'>, True)), Test(IsInstance(Local('b')), Class(<type 'int'>,
True))]), 41, None), Method(<function f_str_42 at 0xb7b00c6c>,
Signature([Test(IsInstance(Local('a')), Class(<type 'str'>, True)),
Test(IsInstance(Local('b')), Class(<type 'int'>, True)),
Test(Comparison(Local('b')), Value(42, True))]), 42, None)], ('stuff',
42), {})


Am I doing something wrong/illegal, or is this just a symptom of me
grabbing code that's not quite working?

thanks,
scott