Most general higher-order constraint describing a sequence of integers ordered with respect to a relation

Question

In CLP(FD), we frequently need to state: \"This is a list of integers and finite domain variables in (sometimes: strictly) ascending/descending order.\"

Is

Answer 1

Quite in the same vein as mapadj/4 presented in an earlier answer... maybe the name is better.

forallAdj(P_2,Xs) :-
   list_forallAdj(Xs,P_2).

list_forallAdj([],_).
list_forallAdj([X|Xs],P_2) :-
   list_forallAdj_prev(Xs,P_2,X).

list_forallAdj_prev([],_,_).
list_forallAdj_prev([X1|Xs],P_2,X0) :-
   call(P_2,X0,X1),
   list_forallAdj_prev(Xs,P_2,X1).

Sample use:

:- use_module(library(clpfd)).
:- use_module(library(lambda)).

?- Ls = [0,_,_,_,_,_], forallAdj(\X0^X1^(X0 + 1 #= X1), Ls).
Ls = [0, 1, 2, 3, 4, 5].

Where could that take us?

• forallAdj => existAdj
• maybe variants with index (forallAdjI, existAdjI) like in Collections.List Module (F#)
• findfirstAdj/pickfirstAdj also like F# find/pick