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use can_be and must_be in library(between)

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This commit is contained in:
Mark Thom
2019-02-24 13:10:31 -07:00
parent 767f98eaa3
commit 7edbb540bd
3 changed files with 17 additions and 11 deletions
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20
src/prolog/lib/between.pl
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@@ -3,6 +3,7 @@
%% TODO: numlist/5.
:- use_module(library(lists), [length/2]).
:- use_module(library(error)).
between(Lower, Upper, Lower) :-
Lower =< Upper.
@@ -19,7 +20,9 @@ enumerate_nats(I0, N) :-
gen_nat(N) :-
integer(N), !, N >= 0.
gen_nat(N) :-
var(N), enumerate_nats(0, N).
var(N), !, enumerate_nats(0, N).
gen_nat(N) :-
throw(error(type_error(integer, N), gen_nat/1)).
enumerate_ints(I, I).
enumerate_ints(I0, N) :-
@@ -32,7 +35,9 @@ enumerate_ints(I0, N) :-
gen_int(N) :-
integer(N), !.
gen_int(N) :-
var(N), enumerate_ints(0, N).
var(N), !, enumerate_ints(0, N).
gen_int(N) :-
throw(error(type_error(integer, N), gen_int/1)).
repeat_integer(N) :-
N > 0.
@@ -40,7 +45,7 @@ repeat_integer(N0) :-
N0 > 0, N1 is N0 - 1, repeat_integer(N1).
repeat(N) :-
integer(N), N > 0, repeat_integer(N).
must_be(integer, N), N > 0, repeat_integer(N).
numlist(Upper, List) :-
( integer(Upper) -> findall(X, between(1, Upper, X), List)
@@ -48,14 +53,14 @@ numlist(Upper, List) :-
).
diag_nats(M, N, M, N).
diag_nats(M, 0, M1, N1) :-
!,
M0 is M+1,
diag_nats(0, M0, M1, N1).
diag_nats(M, N, M1, N1) :-
N > 0, !,
M0 is M+1,
N0 is N-1,
diag_nats(M0, N0, M1, N1).
diag_nats(M, 0, M1, N1) :-
M0 is M+1,
diag_nats(0, M0, M1, N1).
diag_nats(0, 0).
diag_nats(M, N) :-
@@ -82,6 +87,7 @@ diag_ints(M, N) :-
diag_ints(M0, N0, M, N).
gen_ints(L, U) :-
can_be(integer, L), can_be(integer, U),
( integer(L), integer(U), !
; integer(L) -> gen_int(U)
; integer(U) -> gen_int(L)