Crosscut

Now that infix operators seem to be part of the plan, we also need a way to group operations. Consider this example:

f: g: arg

Are we applying f to g, and that returns a function we apply to arg? Or are we applying g to arg, and then f to the result of that? The way editing works right now, it would probably end up as the latter. But we also need a way to express the former.

Fortunately, I don't want tuples, so ( and ) are completely free for that purpose:

( f: g ): arg