Huh? Currying doesn't require any nonlocal reasoning. It's just the convention of preferring functions of type a -> (b -> c) to functions of type (a, b) -> c. (Most programming languages use the latter.)

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boxed an hour ago | parent [-]

Of course it requires non-local reasoning. You either get a function back or a value back depending on if you've passed all the arguments. With normal function calling in C-family languages you know that a function body is called when you do `foo(1, 2, 3)` or you get a compilation error or something. In a currying language you just get a new function back.

	▲	creata 27 minutes ago \| parent [-]
		Functions are just a different kind of value. Needing to know the type of the values you're using when you use them isn't "nonlocal reasoning". And it's not like curried function application involves type-driven parsing or anything. (f x y) is just parsed and compiled as two function calls ((f x) y), regardless of the type of anything involved, just as (x * y * z) is parsed as ((x * y) * z) in mainstream languages. (Except for C, because C actually does have type-driven parsing for the asterisk.) Another way to look at it: languages like Haskell only have functions with one argument, and function application is just written "f x" instead of "f(x)". Everything follows from there. Not a huge difference.