private ASTStatementBase ParseSwitch()
{
Require(TokenType.SWITCH);
if (_switchLevel > 0)
{
throw new ParserException("Nested switch statements are currently not supported.", _lexer.Line, _lexer.Character);
}
Require(TokenType.LEFT_PARENTHESIS);
ASTExpressionBase check = ParseExpression();
Require(TokenType.RIGHT_PARENTHESIS);
Require(TokenType.LEFT_BRACE);
ASTSwitch switchStatement = new ASTSwitch(check);
while (!Match(TokenType.RIGHT_BRACE))
{
if (Match(TokenType.END_OF_FILE))
{
throw new ParserException("'}' expected!", _lexer.Line, _lexer.Character);
}
if (Match(TokenType.DEFAULT))
{
Require(TokenType.DEFAULT);
Require(TokenType.COLON);
_switchLevel++;
switchStatement.AddCase(null, ParseStatement());
_switchLevel--;
if (!Match(TokenType.RIGHT_BRACE))
{
throw new ParserException("A default case must be the final case of a switch statement.", _lexer.Line, _lexer.Character);
}
break;
}
Require(TokenType.CASE);
ASTExpressionBase _case = ParseExpression();
if (_case == null)
{
throw new ParserException("Identifier expected.", _lexer.Line, _lexer.Character);
}
Require(TokenType.COLON);
if (Match(TokenType.CASE) || Match(TokenType.DEFAULT))
{
switchStatement.AddCase(_case, null);
}
else
{
_switchLevel++;
switchStatement.AddCase(_case, ParseStatement());
_switchLevel--;
}
/* for now, I don't think forcing the scripter to use braces to have a "break;" after a case is necessary, eg. in the situation of
* case 5:
* {
* print("hello");
* break;
* }
*
* you might as well just type
* case 5:
* print("hello");
* break;
*/
if (Match(TokenType.BREAK)) // so let's allow that
{
Consume(); // consume 'break'
Require(TokenType.SEMICOLON); // require ';'
var currentCase = switchStatement.Cases[switchStatement.Cases.Count - 1]; // get statement of current case
// and add the 'break' to the end of it
switchStatement.Cases[switchStatement.Cases.Count - 1] = (currentCase.expression,
new ASTBlock(new List <ASTStatementBase>
{
currentCase.statement, new ASTBreak()
}));
}
}
Require(TokenType.RIGHT_BRACE);
if (switchStatement.Cases.Count == 0)
{
throw new ParserException("Empty switch statements are not allowed.", _lexer.Line, _lexer.Character);
}
return(switchStatement);
}
public bool Visit(ASTSwitch node)
{
throw new NotImplementedException();
}
