Pattern match ANY and python sets

[mkmik]

It appears that sets are not correctly matched by ANY:

class Node(Actor):
    def pre_start(self):
        self << ('test', set([1,2,3]))

    def receive(self, msg):
        if msg == ('test', ANY):
            dbg("Got a set", msg)
        else:
            dbg("unhandled msg", msg)

This test prints out "unhandled msg, ('test', set([1,2,3]))"

[erikkaplun]

This is a known issue and hard to fix:

In [1]: from spinoff.util.pattern_matching import ANY

In [2]: ANY == set([])
Out[2]: True

In [3]: ANY == set([1, 2, 3])
Out[3]: True

In [4]: ('test', ANY) == ('test', set([1, 2, 3]))
Out[4]: True

In [5]: ('test', set([1, 2, 3])) == ('test', ANY)
Out[5]: False

In [6]: set([1, 2, 3]) == ANY
Out[6]: False

The reason is that it is Python who decides which operand's __eq__ method gets invoked.

[erikkaplun]

I think the proper solution for this is not to rely on ==—using == could be considered unpythonic anyway. Metacontext however could solve this easily—talking of which, I still haven't had time to look into it...

I should definitely address this issue before Spinoff 1.0.