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$::(?Vars, ?Range, ?Bool)

Reified pure range constraint
Vars
Variable or number, or a list of variables or numbers
Range
Variable or Lo..Hi, where Lo and Hi are variables or numeric expressions
Bool
Variable, 0 or 1

Description

Reified version of $::/2, i.e. the truth value of the range constraint is reflected in the value of the 0/1 variable Bool.

This constraint suspends until its first two arguments are ground. It then unifies Bool according to the truth value of the corresponding $::/2 constraint.

Note: as opposed to $::/2, the first argument cannot be a list.

Modules

This predicate is sensitive to its module context (tool predicate, see @/2).

Examples

    ?- $::(X, 1 .. 5, B), X = 3.0.
    B = 1
    X = 3.0
    Yes (0.00s cpu)

    % range violated
    ?- $::(X, 1 .. 5, B), X = 6.
    B = 0
    X = 6
    Yes (0.00s cpu)
    

See Also

$:: / 2