string CaptureStack()
{
List<object> result = new List<object>();
if (this.TokenString != "")
result.Add(this.TokenString);
StackFrame s = pStack;
while (s != null)
{
object item;
switch(s.tokentype)
{
case EOFFILE:
item = "end_of_file";
break;
case OPEN_TOKEN:
case OPEN_CT_TOKEN:
item = '(';
break;
case CLOSE_TOKEN:
item = ')';
break;
case OPEN_LIST_TOKEN:
item = '[';
break;
case CLOSE_LIST_TOKEN:
item = ']';
break;
case OPEN_CURLY_TOKEN:
item = '{';
break;
case CLOSE_CURLY_TOKEN:
item = '}';
break;
case HEAD_TAIL_SEPARATOR_TOKEN:
item = '|';
break;
case COMMA_TOKEN:
item = ',';
break;
case END_TOKEN:
item = '.';
break;
default:
item = s.term;
break;
}
result.Insert(0, item); // okay, so this is technically quadratic, but the stack shouldn't be deep, and this only runs when syntax errors are thrown
s = s.down;
}
StringWriter sw = new StringWriter();
ISOPrologWriter w = new ISOPrologWriter(sw);
bool first = true;
foreach (var t in result)
{
if (first)
first = false;
else
w.WriteString(" ");
w.Write(t);
}
return sw.ToString();
}
private static void SourceFromPredicateInfo(PredicateIndicator p, PredicateInfo predicateInfo, ISOPrologWriter writer)
{
foreach (var knowledgeBaseEntry in predicateInfo.Entries)
{
var rule = (KnowledgeBaseRule)knowledgeBaseEntry;
var head = new Structure(p.Functor, rule.HeadArgs);
Structure structure;
if (rule.BodyGoals == null || rule.BodyGoals.Length == 0)
{
structure = head;
}
else
{
structure = new Structure(Symbol.Implication, head, Commafy(rule.BodyGoals));
}
writer.Write(structure);
writer.WriteString(".\n");
}
}