5 ms·

Noob question, doesn't partial provides curried functions?

• brandonbloom 13y ago
  Partial application and curried functions are subtly different. Consider a "+" operator that does currying: ((+ 5) 10) If the plus operator is not currying, that's either an arity or type error. You're either not supplying enough arguments to +, or you're trying to do this: (5 10) Partial application can be explicit, without currying: ((partial + 5) 10)
• lmkg 13y ago
  A 'true' curried function in clojure doesn't need partial because it overloads on the arity of the function. It automatically partializes itself if it's called with too few arguments. E.g. you have a function f that takes two arguments, x and y. If the function is truly curried, then (f x y) is a full function call of f that returns a value, while (f x) returns a function of one argument, as if you had used partial. You could create a (two-argument) currying helper-function with the following: (defn curry-2 [f] (fn ([x] (partial f x)) ([x y] (f x y)))) Basically with a currying function, (f x y) and ((f x) y) are equivalent calls, without the need for partial. The reason this isn't more pervasive is because it doesn't play well with optional parameters, &rest parameters, arity overloading, or other ways in which the number of arguments to a function might vary (Haskell permits currying by not allowing variable param lists). Clojure has a couple of library functions that use this pattern (notably, the reducer library), but it's not ubiquitous.
  • moomin 13y ago
    Indeed, that's exactly what poppea does. The code is a generalisation of the code in the reducers library.