/// If arg is another Functor3, then succeed (yield once) if this and arg have the
/// same name and all functor args unify, otherwise fail (don't yield).
/// If arg is a Variable, then call its unify to unify with this.
/// Otherwise fail (don't yield).
public IEnumerable <bool> unify(object arg)
{
arg = YP.getValue(arg);
if (arg is Functor3)
{
Functor3 argFunctor = (Functor3)arg;
if (_name.Equals(argFunctor._name))
{
foreach (bool l1 in YP.unify(_arg1, argFunctor._arg1))
{
foreach (bool l2 in YP.unify(_arg2, argFunctor._arg2))
{
foreach (bool l3 in YP.unify(_arg3, argFunctor._arg3))
{
yield return(false);
}
}
}
}
}
else if (arg is Variable)
{
foreach (bool l1 in ((Variable)arg).unify(this))
{
yield return(false);
}
}
}
public bool termEqual(object term)
{
term = YP.getValue(term);
if (term is Functor3)
{
Functor3 termFunctor = (Functor3)term;
return(_name.Equals(termFunctor._name) && YP.termEqual(_arg1, termFunctor._arg1) &&
YP.termEqual(_arg2, termFunctor._arg2) &&
YP.termEqual(_arg3, termFunctor._arg3));
}
return(false);
}
public bool lessThan(Functor3 functor)
{
// Do the equal check first since it is faster.
if (!_name.Equals(functor._name))
{
return(_name.lessThan(functor._name));
}
if (!YP.termEqual(_arg1, functor._arg1))
{
return(YP.termLessThan(_arg1, functor._arg1));
}
if (!YP.termEqual(_arg2, functor._arg2))
{
return(YP.termLessThan(_arg2, functor._arg2));
}
return(YP.termLessThan(_arg3, functor._arg3));
}
public bool lessThan(Functor3 functor)
{
// Do the equal check first since it is faster.
if (!_name.Equals(functor._name))
return _name.lessThan(functor._name);
if (!YP.termEqual(_arg1, functor._arg1))
return YP.termLessThan(_arg1, functor._arg1);
if (!YP.termEqual(_arg2, functor._arg2))
return YP.termLessThan(_arg2, functor._arg2);
return YP.termLessThan(_arg3, functor._arg3);
}