- See also
- 
numbervars/4, =@=/2 
(variant/2).
- Compatibility
- 
This library was introduced by Quintus and available in many related 
implementations, although not with exactly the same set of predicates.
This library provides the inverse functionality of the built-in
numbervars/3. 
Note that this library suffers from the known issues that '$VAR'(X) is a 
normal Prolog term and, -unlike the built-in numbervars-, the inverse 
predicates do not process cyclic terms. The following predicate 
is true for any acyclic term that contains no '$VAR'(X),
integer(X) terms and no constraint variables:
always_true(X) :-
      copy_term(X, X2),
      numbervars(X),
      varnumbers(X, Copy),
      Copy =@= X2.
- [det]numbervars(+Term)
- 
Number variables in Term using $VAR(N). Equivalent to
numbervars(Term, 0, _).
- See also
- 
numbervars/3, numbervars/4
 
- [det]varnumbers(+Term, 
-Copy)
- 
Inverse of numbervars/1. 
Equivalent to varnumbers(Term, 0, Copy).
- [det]varnumbers(+Term, 
+Start, -Copy)
- 
Inverse of numbervars/3. 
True when Copy is a copy of Term with all 
variables numbered >=Start consistently 
replaced by fresh variables. Variables in Term are shared 
with Copy rather than replaced by fresh variables.
- Errors
- 
domain_error(acyclic_term, Term)if Term is 
cyclic.
- Compatibility
- 
Quintus, SICStus. Not in YAP version of this library
 
- [det]max_var_number(+Term, 
+Start, -Max)
- 
True when Max is the max of Start and the highest 
numbered
$VAR(N) term.
- author
- 
Vitor Santos Costa
- Compatibility
- 
YAP
 
- [det]varnumbers_names(+Term, 
-Copy, -VariableNames)
- 
If Term is a term with numbered and named variables using the 
reserved term '$VAR'(X), Copy is a copy of Term 
where each '$VAR'(X) is consistently replaced by a fresh variable and 
Bindings is a list X = Var, relating the X terms 
with the variable it is mapped to.
- See also
- 
numbervars/3, varnumbers/3, read_term/3 
using the
variable_namesoption.