
term_variables(?Term, -VarList)

   Succeeds if VarList is the list of all variables in Term.



Arguments
   Term                Prolog term.
   VarList             List or variable.

Type
   Term Manipulation

Description
   This predicate collects all the variables inside Term into the list
   VarList.  Every variable occurs only once in VarList, even if it occurs
   several times in Term.  The order of the variables in the list is not
   specified.  As usual, attributed variables are also considered variables.




Modes and Determinism
   term_variables(?, -) is det

Exceptions
     5 --- VarList instantiated but not to a list.

Examples
   
Success:
    term_variables(atom, []).
    term_variables(Term, L).       % gives L = [Term]
    term_variables(f(a,B,c), L).   % gives L = [B]
    term_variables([X,Y,Z], L).    % gives L = [Z,Y,X]
    term_variables([X,Y,X], L).    % gives L = [Y,X]
    term_variables(s(X{a}), L).    % gives L = [X{a}]

Fail:
    term_variables(f(a,B,c), []).





See Also
   nonground / 1, nonground / 2, nonground / 3, nonvar / 1, var / 1
