public void TestOptionalRule()
{
var rule = new OptionalRule(new StringRule("test"));
Assert.IsTrue(rule.Match("test"));
Assert.IsTrue(rule.Match("something"));
}
private Rule Interpret(Grammar grammar, ISemanticNode node)
{
Rule rule = null;
if (node is BranchSemanticNode branch)
{
switch ((EbnfNodeType)branch.NodeType)
{
case EbnfNodeType.Group:
rule = Interpret(grammar, branch.Children[0]);
break;
case EbnfNodeType.Repeat:
rule = new RepeatRule(grammar, Interpret(grammar, branch.Children[0]));
break;
case EbnfNodeType.Optional:
rule = new OptionalRule(grammar, Interpret(grammar, branch.Children[0]));
break;
case EbnfNodeType.Not:
rule = new NotRule(grammar, Interpret(grammar, branch.Children[0]));
break;
case EbnfNodeType.And:
rule = new AndRule(grammar, branch.Children.Select(child => Interpret(grammar, child)));
break;
case EbnfNodeType.Or:
rule = new OrRule(grammar, branch.Children.Select(child => Interpret(grammar, child)));
break;
case EbnfNodeType.None:
rule = Interpret(grammar, branch.Children.Single());
break;
case EbnfNodeType.Root:
case EbnfNodeType.Rule:
case EbnfNodeType.Token:
default:
throw new Exception();
}
}
else if (node is LeafSemanticNode leaf)
{
switch ((EbnfNodeType)leaf.NodeType)
{
case EbnfNodeType.Identifier:
rule = grammar.ReferenceRule(leaf.Value);
break;
case EbnfNodeType.String:
case EbnfNodeType.Regex:
break;
default:
throw new Exception();
}
}
if (rule == null)
{
throw new Exception();
}
else
{
return(rule);
}
}
