// parameter ::=
// identifier | "(" sublist ")"
private Parameter ParseParameter(int position, HashSet<string> names, ParameterKind kind, bool isTyped = false)
{
Token t = PeekToken();
Parameter parameter;
switch (t.Kind) {
case TokenKind.LeftParenthesis: // sublist
string parenWhiteSpace = _lookaheadWhiteSpace;
NextToken();
var parenStart = GetStart();
Expression ret = ParseSublist(names, true);
if (_langVersion.Is7x()) {
ReportSyntaxError(parenStart, GetEnd(), "sublist parameters are not supported in 3.x");
}
bool ateRightParen = Eat(TokenKind.RightParenthesis);
string closeParenWhiteSpace = _tokenWhiteSpace;
TupleExpression tret = ret as TupleExpression;
NameExpression nameRet;
if (tret != null) {
parameter = new SublistParameter(position, tret);
if (_verbatim) {
AddPreceedingWhiteSpace(tret, parenWhiteSpace);
AddSecondPreceedingWhiteSpace(tret, closeParenWhiteSpace);
if (!ateRightParen) {
AddErrorMissingCloseGrouping(parameter);
}
}
} else if ((nameRet = ret as NameExpression) != null) {
parameter = new Parameter(nameRet.Name, kind);
if (_verbatim) {
AddThirdPreceedingWhiteSpace(parameter, (string) _attributes[nameRet][NodeAttributes.PreceedingWhiteSpace]);
AddIsAltForm(parameter);
if (!ateRightParen) {
AddErrorMissingCloseGrouping(parameter);
}
}
} else {
Debug.Assert(ret is ErrorExpression);
ReportSyntaxError(_lookahead);
parameter = new ErrorParameter((ErrorExpression)ret);
AddIsAltForm(parameter);
}
if (parameter != null) {
parameter.SetLoc(ret.IndexSpan);
}
if (_verbatim) {
AddPreceedingWhiteSpace(parameter, parenWhiteSpace);
AddSecondPreceedingWhiteSpace(parameter, closeParenWhiteSpace);
if (!ateRightParen) {
AddErrorMissingCloseGrouping(parameter);
}
}
break;
case TokenKind.Name: // identifier
NextToken();
var name = TokenToName((NameToken)t);
var paramStart = GetStart();
parameter = new Parameter(name.RealName, kind);
if (_verbatim) {
AddPreceedingWhiteSpace(parameter, _tokenWhiteSpace);
AddVerbatimName(name, parameter);
}
if (isTyped && MaybeEat(TokenKind.Colon)) {
if (_verbatim) {
AddThirdPreceedingWhiteSpace(parameter, _tokenWhiteSpace);
}
var start = GetStart();
parameter.Annotation = ParseExpression();
if (_langVersion.Is6x()) {
ReportSyntaxError(start, parameter.Annotation.EndIndex, "invalid syntax, parameter annotations require 3.x");
}
}
CompleteParameterName(parameter, name.RealName, names, paramStart);
break;
default:
ReportSyntaxError(_lookahead);
NextToken();
parameter = new ErrorParameter(_verbatim ? Error(_tokenWhiteSpace + _token.Token.VerbatimImage) : null);
break;
}
return parameter;
}
// SublistParameter
public override bool Walk(SublistParameter node)
{
return ShouldWalkWorker(node);
}
public override bool Walk(SublistParameter node)
{
return true;
}
public override void PostWalk(SublistParameter node)
{
PostWalkWorker(node);
}