/// <summary>
/// Initializes a new instance of the <see cref="Parser"/> class.
/// </summary>
/// <param name="language">The language.</param>
/// <param name="scanner">The scanner.</param>
/// <param name="root">The root.</param>
/// <exception cref="Exception">
/// </exception>
public Parser(LanguageData language, Scanner scanner, NonTerminal root)
{
Language = language;
Context = new ParsingContext(this);
Scanner = scanner ?? language.CreateScanner();
if (Scanner != null)
{
Scanner.Initialize(this);
}
else
{
Language.Errors.Add(GrammarErrorLevel.Error, null, "Scanner is not initialized for this grammar");
}
CoreParser = new CoreParser(this);
Root = root;
if (Root == null)
{
Root = Language.Grammar.Root;
InitialState = Language.ParserData.InitialState;
}
else
{
if (Root != Language.Grammar.Root && !Language.Grammar.SnippetRoots.Contains(Root))
{
throw new Exception(string.Format(Resources.ErrRootNotRegistered, root.Name));
}
InitialState = Language.ParserData.InitialStates[Root];
}
}
public StringSet GetExpectedTermSet()
{
if (CurrentParserState == null)
{
return(new StringSet());
}
//See note about multi-threading issues in ComputeReportedExpectedSet comments.
if (CurrentParserState.ReportedExpectedSet == null)
{
CurrentParserState.ReportedExpectedSet = CoreParser.ComputeGroupedExpectedSetForState(Language.Grammar, CurrentParserState);
}
//Filter out closing braces which are not expected based on previous input.
// While the closing parenthesis ")" might be expected term in a state in general,
// if there was no opening parenthesis in preceding input then we would not
// expect a closing one.
var expectedSet = FilterBracesInExpectedSet(CurrentParserState.ReportedExpectedSet);
return(expectedSet);
}