private void handleString()
{
while (peek() != '"' && !isAtEnd)
{
if (peek() == '\n')
{
line++;
}
advanceScanner();
}
if (isAtEnd)
{
LooxSharp.error(line, "Unterminated string.");
return;
}
//The closing "
advanceScanner();
//Remove the " "
string value = source.Substring(start + 1, current - start - 2);
addToken(TokenType.STRING, value);
}
public void interpret(Expr expr)
{
try
{
object value = evaluate(expr);
Console.WriteLine(stringify(value));
}
catch (RuntimeError err)
{
LooxSharp.runtimeError(err);
}
}
private void scanToken()
{
char c = advanceScanner();
switch (c)
{
//Single characters
case '(': addToken(TokenType.LEFT_PARNTH); break;
case ')': addToken(TokenType.RIGHT_PARNTH); break;
case '{': addToken(TokenType.LEFT_BRACE); break;
case '}': addToken(TokenType.RIGHT_BRACE); break;
case ',': addToken(TokenType.COMMA); break;
case '.': addToken(TokenType.DOT); break;
case '-': addToken(TokenType.MINUS); break;
case '+': addToken(TokenType.PLUS); break;
case ';': addToken(TokenType.SEMICOLON); break;
case '*': addToken(TokenType.STAR); break;
//Double characters
case '!': addToken(match('=') ? TokenType.EXCLAM_EQUAL : TokenType.EXCLAM); break;
case '=': addToken(match('=') ? TokenType.EQUAL_EQUAL : TokenType.EQUAL); break;
case '<': addToken(match('=') ? TokenType.LESS_EQUAL : TokenType.LESS); break;
case '>': addToken(match('=') ? TokenType.GREATER_EQUAL : TokenType.GREATER); break;
//Divide and comment
case '/':
if (match('/'))
{
while (peek() != '\n' && !isAtEnd)
{
advanceScanner();
}
}
else
{
addToken(TokenType.SLASH);
}
break;
//Whitespace
case ' ':
break;
case '\t':
break;
case '\r':
break;
case '\n':
line++;
break;
//Handle strings
case '"': handleString(); break;
default:
//Check for digits (for number literals)
if (basicIsDigit(c))
{
handleNumber();
}
else if (basicIsAlpha(c))
{
handleIdentifier();
}
else
{
LooxSharp.error(line, "Unexpected character.");
}
break;
}
}
private ParseError error(Token token, string msg)
{
LooxSharp.error(token, msg);
return(new ParseError());
}
