/// <summary>
/// Tries to match provided rule one time.
/// </summary>
/// <param name="context">Parsing context</param>
/// <returns>
/// Original branch, if rule doesn't match, otherwise both - original branch and
/// branch with consumed optional match.
/// </returns>
public async Task <IReadOnlyCollection <IParsingContext <TToken> > > Match(IParsingContext <TToken> context)
{
var branchesWithOptionalMatch = await rule.Match(context.Clone());
if (branchesWithOptionalMatch != null && branchesWithOptionalMatch.Count > 0)
{
return
(new List <IParsingContext <TToken> >(branchesWithOptionalMatch)
{
context
});
}
// Optional rule didn't match, return original parsing context
return(new[] { context });
}
/// <summary>
/// Matches decorated parser rule preceeded by necessary global rules.
/// </summary>
/// <param name="context">Parsing context</param>
/// <returns>All possible parsing branches, if rule matches successfully, otherwise null.</returns>
public Task <IReadOnlyCollection <IParsingContext <TToken> > > Match(IParsingContext <TToken> context)
{
var globalRules =
excludedGlobalRules == null || excludedGlobalRules.Count == 0
? context.Grammar.GlobalRules
: context.Grammar.GlobalRules.Where(IsIncludedGlobalRule).ToArray();
if (globalRules.Length > 0)
{
var globalRulesRule =
new ZeroOrMoreTimesRule <TToken>(
globalRules.Length == 1
? globalRules[0]
: new OneOfRule <TToken>(globalRules));
return(new SequenceRule <TToken>(globalRulesRule, rule).Match(context));
}
else
{
return(rule.Match(context));
}
}