add sumlist/2 to lists.pl

This commit is contained in:
Mark Thom
2019-11-30 14:22:59 -07:00
parent a4cacaeab2
commit 27b659c401

View File

@@ -1,7 +1,10 @@
:- module(lists, [member/2, select/3, append/3, memberchk/2,
reverse/2, length/2, maplist/2, maplist/3,
maplist/4, maplist/5, maplist/6, maplist/7,
maplist/8, maplist/9]).
maplist/8, maplist/9, sumlist/2]).
:- use_module(library(error)).
length(Xs, N) :-
@@ -96,3 +99,13 @@ maplist(_, [], [], [], [], [], [], [], []).
maplist(Cont, [E1|E1s], [E2|E2s], [E3|E3s], [E4|E4s], [E5|E5s], [E6|E6s], [E7|E7s], [E8|E8s]) :-
call(Cont, E1, E2, E3, E4, E5, E6, E7),
maplist(Cont, E1s, E2s, E3s, E4s, E5s, E6s, E7s, E8s).
sumlist_([], S, S).
sumlist_([N|Ns], S, S0) :-
S1 is S0 + N,
sumlist(Ns, S, S1).
sumlist(Ns, S) :-
must_be(list, Ns),
sumlist_(Ns, S, 0).