We use a space where a comma is expected to disambiguate between several (slightly obscure) constructs. For example, indirect object notation. Of course, this is totally supportable with the lexical parsing rules changes (yum). However, the language doesn't seem to directly support user defined methods using this trick themselves.

Cheers,
Erik

Light a man a fire, he's warm for a day. Catch a man on fire, and he's warm for the rest of his life. - Terry Pratchet