public void ProvidesAdviceWhenRuleIsUsedBeforeBeingInitialized()
{
var tokens = new CharLexer().Tokenize("123").ToArray();
var numeric = new GrammarRule<string>();
var alpha = new GrammarRule<string>("Alpha");
numeric.FailsToParse(tokens).WithMessage("(1, 1): An anonymous GrammarRule has not been initialized. Try setting the Rule property.");
alpha.FailsToParse(tokens).WithMessage("(1, 1): GrammarRule 'Alpha' has not been initialized. Try setting the Rule property.");
}
public void CanDefineMutuallyRecursiveRules()
{
var tokens = new CharLexer().Tokenize("(A)");
var expression = new GrammarRule<string>();
var alpha = new GrammarRule<string>();
var parenthesizedExpresion = new GrammarRule<string>();
expression.Rule = Choice(alpha, parenthesizedExpresion);
alpha.Rule = from a in Token("A") select a.Literal;
parenthesizedExpresion.Rule = Between(Token("("), expression, Token(")"));
expression.Parses(tokens).WithValue("A");
}