public object VisitPrintStmt(Stmt.Print stmt)
{
object value = Evaluate(stmt.Expr);
Ture.Print(value.ToString());
return(null);
}
public string Interpret(ICollection <Stmt> statements)
{
try
{
foreach (var statement in statements)
{
Execute(statement);
}
}
catch (RuntimeError error)
{
Ture.RuntimeError(error);
}
return(null);
}
private void ScanToken()
{
char c = Advance();
switch (c)
{
case '(': AddToken(LEFT_PAREN); break;
case ')': AddToken(RIGHT_PAREN); break;
case '{': AddToken(LEFT_BRACE); break;
case '}': AddToken(RIGHT_BRACE); break;
case ',': AddToken(COMMA); break;
case '.': AddToken(DOT); break;
case '-': AddToken(MINUS); break;
case '+': AddToken(PLUS); break;
case ';': AddToken(SEMICOLON); break;
case '*': AddToken(STAR); break;
case '!': AddToken(Match('=') ? EXCLAMATION_EQUAL : EXCLAMATION); break;
case '=': AddToken(Match('=') ? EQUAL_EQUAL : EQUAL); break;
case '<': AddToken(Match('=') ? LESS_EQUAL : LESS); break;
case '>': AddToken(Match('=') ? GREATER_EQUAL : GREATER); break;
case '&':
if (Match('&'))
{
AddToken(AND);
}
else
{
Ture.Report(line, null, "Unexpected character.");
}
break;
case '|':
if (Match('|'))
{
AddToken(OR);
}
else
{
Ture.Report(line, null, "Unexpected character.");
}
break;
case '/':
if (Match('/'))
{
while (Peek() != '\n' && !IsAtEnd())
{
Advance();
}
}
else
{
AddToken(SLASH);
};
break;
case ' ':
case '\r':
case '\t':
break;
case '\n':
line++;
break;
case '"': String(); break;
default:
if (IsDigit(c))
{
Number();
}
else if (IsAlpha(c))
{
Identifier();
}
else
{
Ture.Report(line, null, "Unexpected character.");
}
break;
}
}
private ParseError Error(Token token, string message)
{
Ture.Error(token, message);
return(new ParseError());
}
