Created
November 21, 2014 18:49
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Currying, argument reordering, and partial function application in Swift
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| func curry<T, U, R>(binary: (T, U) -> R) -> T -> U -> R { | |
| return { t in | |
| return { u in | |
| return binary(t, u) | |
| } | |
| } | |
| } | |
| func curry<T, U, V, R>(ternary: (T, U, V) -> R) -> T -> U -> V -> R { | |
| return { t in | |
| return { u in | |
| return { v in | |
| return ternary(t, u, v) | |
| } | |
| } | |
| } | |
| } | |
| func curry<T, U, V, W, R>(quaternary: (T, U, V, W) -> R) -> T -> U -> V -> W -> R { | |
| return { t in | |
| return { u in | |
| return { v in | |
| return { w in | |
| return quaternary(t, u, v, w) | |
| } | |
| } | |
| } | |
| } | |
| } | |
| func reorder<T, U, R>(curried: T -> U -> R) -> U -> T -> R { | |
| return { u in | |
| return { t in | |
| return curried(t)(u) | |
| } | |
| } | |
| } | |
| func partial<T, U, R>(binary: (T, U) -> R, argument: T) -> U -> R { | |
| return { u in | |
| return binary(argument, u) | |
| } | |
| } | |
| func partial<T, U, V, R>(ternary: (T, U, V) -> R, t: T) -> (U, V) -> R { | |
| return { u, v in | |
| return ternary(t, u, v) | |
| } | |
| } | |
| func partial<T, U, V, R>(ternary: (T, U, V) -> R, t: T, u: U) -> V -> R { | |
| return { v in | |
| return ternary(t, u, v) | |
| } | |
| } | |
| func partial<T, U, V, W, R>(quaternary: (T, U, V, W) -> R, t: T) -> (U, V, W) -> R { | |
| return { u, v, w in | |
| return quaternary(t, u, v, w) | |
| } | |
| } | |
| func partial<T, U, V, W, R>(quaternary: (T, U, V, W) -> R, t: T, u: U) -> (V, W) -> R { | |
| return { v, w in | |
| return quaternary(t, u, v, w) | |
| } | |
| } | |
| func partial<T, U, V, W, R>(quaternary: (T, U, V, W) -> R, t: T, u: U, v: V) -> W -> R { | |
| return { w in | |
| return quaternary(t, u, v, w) | |
| } | |
| } | |
| let addThree = partial(+, 3) | |
| let eight = addThree(5) | |
| let curriedDivide: Int -> Int -> Int = curry(/) | |
| let tenDividedBy = curriedDivide(10) | |
| let two = tenDividedBy(5) | |
| let divideByTen = reorder(curriedDivide)(10) | |
| let four = divideByTen(40) | |
| func printFourThings(thing1: String, thing2: String, thing3: String, thing4: String) { | |
| println(thing1) | |
| println(thing2) | |
| println(thing3) | |
| println(thing4) | |
| } | |
| let greetTheWorldAnd = partial(printFourThings, "hello, world", "and") | |
| greetTheWorldAnd("let's get", "some nachos") |
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