internal void InitSpecialRuleRef(Backend backend, ParseElementCollection parent)
{
Rule rule = null;
switch (_type)
{
case SpecialRuleRefType.Null:
parent.AddArc(backend.EpsilonTransition(1f));
break;
case SpecialRuleRefType.Void:
rule = backend.FindRule("VOID");
if (rule == null)
{
rule = backend.CreateRule("VOID", (SPCFGRULEATTRIBUTES)0);
((IElement)rule).PostParse((IElement)parent);
}
parent.AddArc(backend.RuleTransition(rule, parent._rule, 1f));
break;
case SpecialRuleRefType.Garbage:
{
OneOf oneOf = new OneOf(parent._rule, backend);
oneOf.AddArc(backend.RuleTransition(CfgGrammar.SPRULETRANS_WILDCARD, parent._rule, 0.5f));
oneOf.AddArc(backend.EpsilonTransition(0.5f));
((IElement)oneOf).PostParse((IElement)parent);
break;
}
}
}
/// <summary>
/// Returns the initial state of a special rule.
/// For each type of special rule we make a rule with a numeric id and return a reference to it.
/// </summary>
internal void InitSpecialRuleRef(Backend backend, ParseElementCollection parent)
{
Rule rule = null;
// Create a transition corresponding to Special or Uri
switch (_type)
{
case SpecialRuleRefType.Null:
parent.AddArc(backend.EpsilonTransition(1.0f));
break;
case SpecialRuleRefType.Void:
rule = backend.FindRule(szSpecialVoid);
if (rule == null)
{
rule = backend.CreateRule(szSpecialVoid, 0);
// Rule with no transitions is a void rule.
((IRule)rule).PostParse(parent);
}
parent.AddArc(backend.RuleTransition(rule, parent._rule, 1.0f));
break;
case SpecialRuleRefType.Garbage:
// Garbage transition is optional whereas Wildcard is not. So we need additional epsilon transition.
OneOf oneOf = new(parent._rule, backend);
// Add the garbage transition
oneOf.AddArc(backend.RuleTransition(CfgGrammar.SPRULETRANS_WILDCARD, parent._rule, 0.5f));
// Add a parallel epsilon path
oneOf.AddArc(backend.EpsilonTransition(0.5f));
((IOneOf)oneOf).PostParse(parent);
break;
default:
System.Diagnostics.Debug.Assert(false, "Unknown special ruleref type");
break;
}
}
