I don’t think named arguments are as much a problem as function overloading and optional parameters for this.

Without overloading you could define the answer as

    g(x) { f(fst:x, snd:y) }

always which would make partial application somewhat ergonomic but makes allowing fst without snd horribly ugly when you have to pass in some spiritual null or _ to.

I think these ideas are fundamentally opposed and so I don’t think there’s a good way to have a nice syntax for both.