[Haskell-beginners] Confusion over currying, , lambda, and closures
Bob Ippolito
bob at redivi.com
Thu Dec 24 04:02:17 UTC 2020
The steps and semantics are the same, the only meaningful difference is
syntax.
These two definitions are indistinguishable:
f x = y
f = \x -> y
In basically the same way that these two expressions are:
(+) 1 2
1 + 2
In Haskell there are many cases where a more convenient but equivalent
syntax exists to express certain terms. This is referred to as syntax sugar.
On Wed, Dec 23, 2020 at 19:12 Lawrence Bottorff <borgauf at gmail.com> wrote:
> I have these three versions of addition
>
> addA x y = x + y
> addB x = \y -> x + y
> addC = \x -> \y -> x + y
>
> and all three add two arguments just fine
>
> > addA 2 3
> 5
> > addB 2 3
> 5
> > addC 2 3
> 5
>
> but I can't see how addB and addC are actually accomplishing this. addA is
> currying, which I don't fully follow. addC I understand beta reduction-wise
>
> (\x -> \y -> x + y) 2 3
> (\y -> 2 + y) 3
> (2 + 3)
> 5
>
> but I don't understand addB and what steps are happening currying/beta
> reduction-wise. Can someone break down the steps with addA and addB?
>
> LB
>
>
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