private void WalkGoal(KnowledgeBase kb, KnowledgeBaseRule rule, object goal)
{
goal = Term.Deref(goal);
var atom = goal as Symbol;
if (atom != null)
{
var p = new PredicateIndicator(atom, 0);
if (PrologPrimitives.IsDefined(p))
{
return;
}
var predicate = kb.CheckForPredicateInfo(p);
if (predicate == null)
{
rule.PrintWarning("undefined predicate {0}", p);
}
else
{
MarkReferenced(predicate);
}
}
else
{
var s = goal as Structure;
if (s != null)
{
WalkGoal(kb, rule, s);
}
else if (!(goal is LogicVariable) && !(goal is bool))
{
rule.PrintWarning("malformed goal: {0}", goal);
}
}
}
/// <summary>
/// True if the specified functor/arity is undefined.
/// </summary>
public bool Undefined(PredicateIndicator p)
{
if (PrologPrimitives.IsDefined(p))
return false;
if (CheckForPredicateInfoInThisKB(p) != null)
return false;
foreach (KnowledgeBase import in imports)
if (!import.Undefined(p))
return false;
return true;
}
/// <summary>
/// True if the specified functor/arity is undefined.
/// </summary>
public bool Undefined(PredicateIndicator p)
{
if (PrologPrimitives.IsDefined(p))
{
return(false);
}
if (CheckForPredicateInfoInThisKB(p) != null)
{
return(false);
}
foreach (KnowledgeBase import in imports)
{
if (!import.Undefined(p))
{
return(false);
}
}
return(true);
}
private void WalkGoal(KnowledgeBase kb, KnowledgeBaseRule rule, Structure goal)
{
var predicateIndicator = goal.PredicateIndicator;
Symbol functor = goal.Functor;
int arity = goal.Arity;
switch (functor.Name)
{
case "begin":
foreach (var arg in goal.Arguments)
{
WalkGoal(kb, rule, arg);
}
break;
case "once":
case "check":
case "randomize":
case "not":
case "\\+":
if (arity == 1)
{
WalkGoal(kb, rule, goal.Argument(0));
}
else
{
WarnUndefined(rule, functor, arity);
}
break;
case ",":
case ";":
case "->":
if (arity == 2)
{
WalkGoal(kb, rule, goal.Argument(0));
WalkGoal(kb, rule, goal.Argument(1));
}
else
{
WarnUndefined(rule, functor, arity);
}
break;
case "call":
case "maplist":
if (arity < 1)
{
WarnUndefined(rule, functor, arity);
}
else
{
object goalToCall = goal.Argument(0);
var goalToCallAsStructure = goalToCall as Structure;
if (goalToCallAsStructure != null)
{
var newArgs = new object[arity - 1 + goalToCallAsStructure.Arity];
goalToCallAsStructure.Arguments.CopyTo(newArgs, 0);
WalkGoal(kb, rule, new Structure(goalToCallAsStructure.Functor, newArgs));
}
else
{
var call = goalToCall as Symbol;
if (call != null)
{
this.WalkGoal(kb, rule, new Structure(call, new object[arity - 1]));
}
}
}
break;
case "arg_min":
case "arg_max":
if (arity == 3)
{
WalkGoal(kb, rule, goal.Argument(2));
}
else
{
WarnUndefined(rule, functor, arity);
}
break;
case "find_all":
if (arity == 3)
{
WalkGoal(kb, rule, goal.Argument(1));
}
else
{
WarnUndefined(rule, functor, arity);
}
break;
default:
if (PrologPrimitives.IsDefined(predicateIndicator))
{
var arglist = PrologPrimitives.Arglist(predicateIndicator.Functor);
for (int i = 0; i < Math.Min(predicateIndicator.Arity, arglist.Count); i++)
{
var argSym = arglist[i] as Symbol;
if (argSym != null)
{
var arg = argSym.Name;
if (arg[0] == ':')
{
WalkGoal(kb, rule, goal.Argument(i));
}
else if (arg == "..." && arglist[i - 1] is string && ((string)arglist[i - 1])[0] == ':')
{
// Predicate accepts a rest arg of goals
for (int j = i; j < predicateIndicator.Arity; j++)
{
WalkGoal(kb, rule, goal.Argument(j));
}
}
}
}
}
else
{
var predicate = kb.CheckForPredicateInfo(predicateIndicator);
if (predicate == null)
{
WarnUndefined(rule, functor, arity);
}
else
{
MarkReferenced(predicate);
if (predicate.HigherOrderArguments != null)
{
foreach (int argIndex in predicate.HigherOrderArguments)
{
WalkGoal(kb, rule, goal.Argument(argIndex));
}
}
}
}
break;
}
}