// ReSharper disable once ParameterTypeCanBeEnumerable.Local
private static IEnumerable<CutState> DeclarationDriver(DeclarationHandler handler, object[] args,
PrologContext context)
{
foreach (var arg in args)
{
object indicator = Term.Deref(arg);
var t = indicator as Structure;
if (t != null && t.IsFunctor(Symbol.Comma, 2))
{
#pragma warning disable 168
// ReSharper disable UnusedVariable
foreach (var ignore1 in DeclarationDriver(handler, new[] {t.Argument(0)}, context))
foreach (var ignore2 in DeclarationDriver(handler, new[] {t.Argument(1)}, context))
// ReSharper restore UnusedVariable
#pragma warning restore 168
yield return CutState.Continue;
}
else if (t != null && t.IsFunctor(Symbol.PrologListConstructor, 2))
{
// List argument
while (t != null)
{
handler(PredicateIndicator.FromExpression(t.Argument(0)), context);
object rest = t.Argument(1);
if (rest == null)
t = null;
else
{
t = rest as Structure;
if (t == null || !t.IsFunctor(Symbol.PrologListConstructor, 2))
throw new ArgumentException("Argument is an improper list.");
}
}
}
else
{
handler(PredicateIndicator.FromExpression(indicator), context);
yield return CutState.Continue;
}
}
}
private static PrimitiveImplementation MakeDeclarationPredicate(DeclarationHandler handler)
{
return (args, context) => DeclarationDriver(handler, args, context);
}
