%   File   : XREF.DEF
%   Authors: Dave Bowen, Chris Mellish
%   Updated: 15 September 1984
%   Purpose: System definitions for use with XREF.PL.

%   These are the predicates which are part of the basic Prolog system.

system([_|_]).
system(abolish(_,_)).
system(revive(_,_)).
system(incore(_)).
system(asserta(_,_)).
system(asserta(_)).
system(assertz(_,_)).
system(assertz(_)).
system(retract(_)).
system(clause(_,_,_)).
system(clause(_,_)).
system(recorda(_,_,_)).
system(recordz(_,_,_)).
system(recorded(_,_,_)).
system(instance(_,_)).
system(erase(_)).
system(true).
system(length(_,_)).
system(name(_,_)).
system(op(_,_,_)).
system(var(_)).
system(atom(_)).
system(!).
system(statistics).
system(statistics(_,_)).
system(functor(_,_,_)).
system(call(_)).
system(expand_term(_,_)).
system(debug).
system(debugging).
system(display(_)).
system(get(_)).
system(get0(_)).
system(leash(_)).
system(nl).
system(nodebug).
system(print(_)).
system(put(_)).
system(skip(_)).
system(tab(_)).
system(trace).
system(ttyflush).
system(ttyget(_)).
system(ttyget0(_)).
system(ttynl).
system(ttyput(_)).
system(ttyskip(_)).
system(ttytab(_)).
system(write(_)).
system(writeq(_)).
system(ancestors(_)).
system(depth(_)).
system(maxdepth(_)).
system(subgoal_of(_)).
system(abort).
system(arg(_,_,_)).
system(assert(_)).
system(atomic(_)).
system(bagof(_,_,_)).
system(break).
system(close(_)).
system(compare(_,_,_)).
system(compile(_)).
system(consult(_)).
system(current_atom(_)).
system(current_functor(_,_)).
system(current_predicate(_,_)).
system(current_op(_,_,_)).
system(fail).
system(fileerrors).
system(gc).
system(gcguide(_)).
system(halt).
system(integer(_)).
system(keysort(_,_)).
system(listing).
system(listing(_)).
system(log).
system(mode(_)).		% not an evaluable predicate
system(nofileerrors).
system(nogc).
system(nolog).
system(nonvar(_)).
system(numbervars(_,_,_)).
system('C'(_,_,_)).		% generated in grammar rules
system(phrase(_,_)).
system(prompt(_,_)).
system(public(_)).		% not an evaluable predicate
system(read(_)).
system(reconsult(_)).
system(rename(_,_)).
system(repeat).
system(restore(_)).
system(save(_)).
system(save(_,_)).
system(see(_)).
system(seeing(_)).
system(seen).
system(setof(_,_,_)).
system(sort(_,_)).
system(tell(_)).
system(telling(_)).
system(told).
system(trimcore).
system(plsys(_)).
system(end_of_file).
system('LC').
system('NOLC').
system(\+_).
system((_->_)).
system(spy _).
system(nospy _).
system(_=_).
system(_ is _).
system(_==_).
system(_\==_).
system(_=.._).
system(_<_).
system(_>_).
system(_=<_).
system(_>=_).
system(_@<_).
system(_@=<_).
system(_@>=_).
system(_@>_).
system(_^_).
system(_=\=_).
system(_=:=_).

applies(call(Goal), Goal).
applies(phrase(Nonterminal, List), Nonterminal+2).
applies(bagof(Vars,Test,Bag), Test).
applies(setof(Vars,Test,Set), Test).
applies((P->Q), (P,Q)).
applies(X^P, P).
applies(\+G, G).