I don't know if this is already provided by current specifications, but since I know of Perl6 that is will support quite a powerful system of function prototyping ("signatures"?), I wonder wether it will be possible to specify a (finite number of) argument(s) on the left of functions, thus allowing to create user-defined operators. I had tried sml (a functional language) and despite its being really simple if compared to Perl, it provided this functionality...
Michele -- Dante, _The Inferno_, in particular the line about, ``Abandon all hope ye who enter here.'' - William F. Adams in comp.text.tex, "Re: Book Suggestion for MS Word?"