4.21 Analysing and Constructing Terms
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Availability:built-in
var_number(@Term, -VarNumber)
True if Term is numbered by numbervars/3 and VarNumber is the number given to this variable. This predicate avoids the need for unification with '$VAR'(X) and opens the path for replacing this valid Prolog term by an internal representation that has no textual equivalent.
ClioPatria (version V3.1.1-40-g9d9e003)