Re: why is acc here unbound

Hi Roelof,

in your function length, acc is defined as an argument of the inner
function length2, so it is only available in the body of length2. Your use
of acc is outside of this scope, that's why OCaml complains here that acc
in undefined: there is no value acc defined in the scope of the expression
"acc 0 list2 list".

HTH,
ph.

2014-11-05 16:25 GMT+01:00 Roelof Wobben [email protected] [ocaml_beginners]
<[email protected]>:

> Hello,
>
> I have this :
>
> let length list =
>      let rec length2 list2 acc =
>          match list2 with
>             | [] -> acc
>             | x::xs -> length2 xs (acc + 1)
>      in acc 0 list2 list ;;
>
> But as soon as I copie it into the ocaml prompt I see a message that the
> acc in the part in acc 0 list2 list is unbound.
>
> Roelof
>
>
>
>
>
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> Posted by: Roelof Wobben <[email protected]>
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