private void checkUnaryMinus(LexemaSequence input, Lexema lexema)
{
if (lexema.symbol == Expression.MINUS)
{
bool must_change = false;
if (input.GetPosition() > 1)
{
char symbol = input.getLexema(input.GetPosition() - 2).symbol;
if ((symbol == Expression.ASSIGNMENT) ||
(symbol == Expression.OPEN_BRACE) ||
(symbol == Expression.PLUS) ||
(symbol == Expression.MULTUPLICATION) ||
(symbol == Expression.BITWISE_OR) ||
(symbol == Expression.DIVISION) ||
(symbol == Expression.MODUL) ||
(symbol == Expression.BITWISE_AND) ||
(symbol == Expression.BITWISE_INVERSION) ||
(symbol == Expression.BOOLEAN_INVERSION))
{
must_change = true;
}
}
else
{
must_change = true;
}
if (must_change)
{
lexema.symbol = Expression.UNARY_MINUS;
}
}
}
private bool changeSymbol(LexemaSequence input, Lexema lexema, char search_symbol,
char replace_symbol)
{
if (lexema.symbol == search_symbol)
{
if (input.GetPosition() > 1)
{
if (input.getLexema(input.GetPosition() - 2).symbol == Expression.IDENTIFIER)
{
lexema.symbol = replace_symbol;
return(true);
}
}
if (input.GetPosition() < input.size())
{
if (input.peekLexema().symbol == Expression.IDENTIFIER)
{
//това е префиксна операция, не се прави заместване
return(true);
}
else
{
Console.WriteLine(search_symbol + " can be applyed only to identifier.");
return(false);
}
}
Console.WriteLine("Error 1002.");
return(false);
}
else
{
return(true);
}
}