current_advice/3 development

Synopsis

current_advice(*Goal, *Port, *Action)

Provides a means for checking what advice is present.

Arguments

Goal callable [MOD]

any term.

Port one of [call,exit,done,redo,fail]

Action callable [MOD]

any term.

Description

Unifies Goal with the goal term, Port with the port, and Action with the action term of currently existing user-defined advice. None of the three arguments need to be instantiated.

This predicate is not supported in runtime systems.

Tips

To backtrack through all the advice that exists for a predicate mypred/2, you can use the goal

     | ?- current_advice(mypred(_,_), Port, Action).
     

If you are only interested in the advice for mypred/2 on the call port, use

     | ?- current_advice(mypred(_,_), call, Action).
     

To determine what predicates you told to call format/2, use

     | ?- current_advice(Goal, Port, format(_,_)).
     

See Also

add_advice/3, remove_advice/3, check_advice/[0,1], nocheck_advice/[0,1]