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Does this operation exist?
f#

Situations often arise where I need to curry the second argument of a function. For example, the divisor in (/). It’s not hard to come up with a function or operator for doing this, as the following code illustrates. But is there a way to do it in F# without defining a new function or operator?

p.s. Sorry I messed up the code tags; it's pretty simple code in any case.

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let fRev f a b = f b a
let (><) f a b = f b a
let z f a b = f b a
let thisIs20 = ((/) >< 5) 100
let also20 = ((><) (/) 5) 100
let d5'0 = fRev (/) 5
let d5'1 = (/) >< 5
let m5'0 = fRev (%) 5
let m5'1 = (%) >< 5
let t0 = d5'0 99 // 19
let t1 = d5'1 99 // 19
let t2 = m5'0 99 // 4
let t3 = m5'1 99 // 4
let divBy = (><) (/)
let divBy5 = divBy 5
let shouldBe20 = divBy5 100
.

I think the 'flip' operator may deserve a built-in implementation in future F# versions.

By on 6/15/2010 9:30 AM ()

I would love to see a standard way to curry arguments in alternative order, especially flipping a two-argument function.

This kind of operation is also very common in stack-based languages like FORTH, where you have the "swap" word, etc.

-Neil

By on 6/16/2010 7:12 AM ()

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