Module between

:- use_module(library(between)).

Predicates that generate integers

These predicates can be used to reason about integers in a reduced domain that follow some property. library(clpz) provides another way of reasoning about integers that may also be interesting.

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between(+Lower, +Upper, -X).

Given Lower and Upper are both integer numbers, true iff X is an integer so that Lower =< X =< Upper. Can be used both to check if X is between Lower and Upper or to generate an integer between Lower and Upper.

Examples:


?- between(10, 20, 15).
   true.
?- between(10, 20, 25).
   false.
?- between(3, 5, X).
   X = 3
;  X = 4
;  X = 5.

gen_nat(?N)

True iff N is a natural number.

gen_int(?N)

True iff N is an integer.

repeat(+N)

Succeeds N times. This predicate is only included for compatibility and should not be used because it lacks a declarative interpretation.

numlist(?Upper, ?List)

True iff List is the list of integers [1, ..., Upper]. Example:


?- numlist(X, Y).
   X = 1, Y = [1],
;  X = 2, Y = [1,2]
;  X = 3, Y = [1,2,3]
; ... .

numlist(?Lower, ?Upper, ?List).

True iff List is a list of the form [Lower, ..., Upper]. Example:


?- numlist(5, 10, X).
   X = [5,6,7,8,9,10].