I think you intended to send this to a different forum/mailinglist… It's
for sure no J ;).
Cheers,
Jan-Pieter
On Fri, 14 Oct 2022, 12:38 Razetime, <rraghu.11...@gmail.com> wrote:
> Currently I have these two predicates in my program that I think I can
> make deterministic.
>
> :- pred entry(list(string)::in, list(int)::out) is det.
> entry(Dirs, Out) :-
> map((pred(X::in, [L,R]::out) is det :-
> split(X, 1, L, R)),
> Dirs, Spl),
> foldl2((pred([T, B]::in, D::in, Ds::out, P::in, Ps::out) is det :-
> rot(T, D, Ds),
> BI = string.det_to_int(B),
> map((pred(X::in, Y::out) is det :- Y = X*BI), Ds, Dso),
> map_corresponding((pred(X::in, Y::in, Z::out) is det :- Z
> = X+Y), P, Dso, Ps)
> ), Spl, [0, 1], _, [0, 0], Out).
>
> :- pred rot(string::in, list(int)::in, list(int)::out) is det.
> rot("L", [X, Y], [A, B]) :-
> A = -Y,
> B = X.
> rot("R", [X, Y], [A, B]) :-
> A = Y,
> B = -X.
>
> I'm having trouble with both of these since they're giving me problems
> with determinism inference:
>
> a01.m:017: In `entry'(in, out):
> a01.m:017: Determinism error in lambda expression.
> a01.m:017: Declared `det', inferred `semidet''.
> a01.m:017: In argument 1 of clause head:
> a01.m:017: in argument 2 of functor `[|]/2':
> a01.m:017: in argument 2 of functor `[|]/2':
> a01.m:017: unification with `list.[]' can fail.
> a01.m:017: In argument 1 of clause head:
> a01.m:017: in argument 2 of functor `[|]/2':
> a01.m:017: unification with `list.[B | V_35]' can fail.
> a01.m:017: In argument 1 of clause head:
> a01.m:017: unification of `LambdaHeadVar__1' and `list.[T | V_34]' can
> fail.
> a01.m:024: In `rot'(in, in, out):
> a01.m:024: error: determinism declaration not satisfied.
> a01.m:024: Declared `det', inferred `semidet'.
> a01.m:024: The reasons for the difference are the following.
> a01.m:025: The switch on HeadVar__1 can fail.
> a01.m:025: In argument 2 of clause head:
> a01.m:025: in argument 2 of functor `[|]/2':
> a01.m:025: in argument 2 of functor `[|]/2':
> a01.m:025: unification with `list.[]' can fail.
> a01.m:025: In argument 2 of clause head:
> a01.m:025: in argument 2 of functor `[|]/2':
> a01.m:025: unification with `list.[V_23 | V_22]' can fail.
> a01.m:025: In argument 2 of clause head:
> a01.m:025: unification of `HeadVar__2' and `list.[V_21 | V_20]' can fail.
>
> how do i make sure that these functions that use a pattern match are
> det? Adding a branch with ; for the error cases makes it multi, but I
> want to know how i can make it return a single value for every set of
> arguments.
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>
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