Hi,
Sorry if this was previously discussed but it's something I miss in
Python. I get around this using isinstance() but it would be cleaner
to have separate functions with the same name but different argument
types. I think the idea gets quite close to the Lisp/CLOS
implementation of methods.
Below is just simple implementation example (and class functions are
not supported) but it can be further extended/optimised/modified for
better type detection like issubclass() etc. The idea is similar to
the @accepts decorator:
methods = dict()
def method(*types):
def build_method(f):
assert len(types) == f.func_code.co_argcount
if not f.func_name in methods:
methods[f.func_name] = dict()
methods[f.func_name][str(types)] = f
def new_f(*args, **kwds):
type_str = str(tuple([type(arg) for arg in args]))
assert type_str in methods[f.func_name]
return methods[f.func_name][type_str](*args, **kwds)
new_f.func_name = f.func_name
return new_f
return build_method
And its utilisation:
@method(int)
def test(arg):
print 'int', arg
@method(float)
def test(arg):
print 'float', arg
test(1) # succeeds
test(1.5) # succeeds
test(1, 2) # assert fails
test('aaa') # assert fails
Let me know what you think. Thanks.
--
Catalin
--
http://mail.python.org/mailman/listinfo/python-list
