static SyntaxTree ParseInternal(SourceText sourceText,
[CanBeNull] Func <GdGrammar, ParserRuleContext> treeCreator,
CancellationToken cancellationToken)
{
treeCreator ??= (p => p.guiDescription());
var diagnostics = ImmutableArray.CreateBuilder <Diagnostic>();
// Setup Lexer
var stream = sourceText.ToCharStream();
var lexer = new GdTokens(stream);
var lexerErrorListener = new GdLexerErrorListener(sourceText, diagnostics);
lexer.RemoveErrorListeners();
lexer.AddErrorListener(lexerErrorListener);
// Setup Parser
var cts = new GdCommonTokenStream(lexer);
var parser = new GdGrammar(cts);
var parserErrorListener = new GdParserErrorListener(sourceText, diagnostics);
parser.RemoveErrorListeners();
parser.AddErrorListener(parserErrorListener);
var tree = treeCreator(parser);
cancellationToken.ThrowIfCancellationRequested();
var errorNodes = new ErrorNodeVisitor();
errorNodes.Visit(tree);
cancellationToken.ThrowIfCancellationRequested();
var tokens = TokenFactory.CreateTokens(cts, errorNodes.ErrorNodes);
var visitor = new GdSyntaxSlotBuilder(tokens);
var slot = visitor.Visit(tree);
return(new SyntaxTree(sourceText, slot, diagnostics.ToImmutableArray()));
}
