switchcase.py

class case(object):
    EMPTY_CASE = (None for x in [1])
    def __init__(self, *args):
        self.cases = args
        self.used = False

    def __iter__(self):
        return self

    def next(self):
        if not self.used:
            self.used = True
            return 1
        else:
            raise StopIteration

def switch(var, *cases):
    dispatch = {}
    for c in cases:
        cond = c.gi_frame.f_locals[".0"].cases
        dispatch.update({case_val: c for case_val in cond})

    print dispatch
    return dispatch.get(var, case.EMPTY_CASE).next()

__builtins__['case'] = case
__builtins__['switch'] = switch

test_switch.py

import switchcase

x = 5
print switch(x, ("Odd" for x in case(1, 3, 5)),
                ("Even" for x in case(2, 4, 6)))