How to write a partially applied function for subtraction specifying the subtrahend?

Question

I am trying to write a function that decrements by one -- something like what I would expect (-1) to do as a partially applied infix with specified subtrahend. However, written that way ghc appears to read the - not as a subtraction operator but as a negation.

> :t (-1)
(-1) :: Num a => a

How can I concisely write a decrement operator?

score 1 · Accepted Answer · answered Oct 04 '17 at 02:56

1

You'd use subtract, which exists specifically for this purpose:

subtract 1

answered Oct 04 '17 at 02:56

melpomene

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And, in general, there’s `flip`. – Davislor Oct 04 '17 at 05:47

How to write a partially applied function for subtraction specifying the subtrahend?

1 Answers1