SWI-Prolog -- bounded

Availability:built-in

[det]bounded_number(?Low, ?High, +Num)

True if Low < Num < High. Raises a type error if Num is not a number. This predicate can be used both to check and generate bounds across the various numeric types. Note that a number cannot be bounded by itself and NaN, Inf, and -Inf are not bounded numbers.

If Low and/or High are variables they will be unified with tightest values that still meet the bounds criteria. The generated bounds will be integers if Num is an integer; otherwise they will be floats (also see nexttoward/2 for generating float bounds). Some examples:

?- bounded_number(0,10,1).
true.

?- bounded_number(0.0,1.0,1r2).
true.

?- bounded_number(L,H,1.0).
L = 0.9999999999999999,
H = 1.0000000000000002.

?- bounded_number(L,H,-1).
L = -2,
H = 0.

?- bounded_number(0,1r2,1).
false.

?- bounded_number(L,H,1.0Inf).
false.