private void ScanNumber()
{
string scannedSymbol = "";
bool hasDecimalSeparator = false;
char prevCh = currentCharacter.Value;
while (LexicalUtils.IsDigit(currentCharacter.Value) || LexicalUtils.IsDecimalSeparator(currentCharacter.Value))
{
if (LexicalUtils.IsDecimalSeparator(currentCharacter.Value))
{
if (hasDecimalSeparator)
{
if (LexicalUtils.IsDecimalSeparator(prevCh))
{
CurrentSymbol = SymbolEnum.IntConstant;
IntConstant = int.Parse(scannedSymbol.Substring(0, scannedSymbol.Length - 1));
symbolQueue.Enqueue(SymbolEnum.TwoDots);
currentCharacter = ioModule.NextCh();
return;
}
else
{
break;
}
}
hasDecimalSeparator = true;
}
scannedSymbol += currentCharacter.Value.ToString();
prevCh = currentCharacter.Value;
currentCharacter = ioModule.NextCh();
}
if (hasDecimalSeparator)
{
double result;
if (double.TryParse(scannedSymbol, NumberStyles.Any, CultureInfo.InvariantCulture, out result) && result < MAX_FLOAT_CONSTANT)
{
CurrentSymbol = SymbolEnum.RealConstant;
FloatConstant = result;
}
else
{
Error = ioModule.AddError(207, CurrentLineNumber, CurrentPositionInLine);
}
}
else
{
int result;
if (int.TryParse(scannedSymbol, out result) && result < MAX_INT_CONSTANT)
{
CurrentSymbol = SymbolEnum.IntConstant;
IntConstant = result;
}
else
{
Error = ioModule.AddError(203, CurrentLineNumber, CurrentPositionInLine);
}
}
}
private void ScanIdentifier()
{
string scannedSymbol = "";
while (LexicalUtils.IsIdentifierChar(currentCharacter.Value))
{
scannedSymbol += currentCharacter.Value.ToString();
currentCharacter = ioModule.NextCh();
}
SymbolEnum keyword;
if (Symbol.keywordMapping.TryGetValue(scannedSymbol, out keyword))
{
CurrentSymbol = keyword;
}
else
{
CurrentSymbol = SymbolEnum.Identifier;
NameTable.Add(scannedSymbol);
IdentifierName = scannedSymbol;
}
}
private void ScanSymbol()
{
if (LexicalUtils.IsDigit(currentCharacter.Value))
{
ScanNumber();
}
else if (LexicalUtils.IsStringConstantStart(currentCharacter.Value))
{
ScanString();
}
else if (LexicalUtils.IsIdentifierStart(currentCharacter.Value))
{
ScanIdentifier();
}
else
{
switch (currentCharacter.Value)
{
case '<':
currentCharacter = ioModule.NextCh();
if (currentCharacter.Value == '=')
{
CurrentSymbol = SymbolEnum.LessEquals;
currentCharacter = ioModule.NextCh();
}
else
{
if (currentCharacter.Value == '>')
{
CurrentSymbol = SymbolEnum.NotEquals;
currentCharacter = ioModule.NextCh();
}
else
{
CurrentSymbol = SymbolEnum.Less;
}
}
break;
case '>':
currentCharacter = ioModule.NextCh();
if (currentCharacter.Value == '=')
{
CurrentSymbol = SymbolEnum.GreaterEquals;
currentCharacter = ioModule.NextCh();
}
else
{
CurrentSymbol = SymbolEnum.Less;
}
break;
case ':':
currentCharacter = ioModule.NextCh();
if (currentCharacter.Value == '=')
{
CurrentSymbol = SymbolEnum.Assign;
currentCharacter = ioModule.NextCh();
}
else
{
CurrentSymbol = SymbolEnum.Colon;
}
break;
case '+':
CurrentSymbol = SymbolEnum.Plus;
currentCharacter = ioModule.NextCh();
break;
case '-':
CurrentSymbol = SymbolEnum.Minus;
currentCharacter = ioModule.NextCh();
break;
case '*':
CurrentSymbol = SymbolEnum.Star;
currentCharacter = ioModule.NextCh();
break;
case '/':
CurrentSymbol = SymbolEnum.Slash;
currentCharacter = ioModule.NextCh();
break;
case '=':
CurrentSymbol = SymbolEnum.Equals;
currentCharacter = ioModule.NextCh();
break;
case '(':
currentCharacter = ioModule.NextCh();
if (currentCharacter.Value == '*')
{
ScanMultilineComment();
}
else
{
CurrentSymbol = SymbolEnum.LeftRoundBracket;
}
break;
case ')':
CurrentSymbol = SymbolEnum.RightRoundBracket;
currentCharacter = ioModule.NextCh();
break;
case '[':
CurrentSymbol = SymbolEnum.LeftSquareBracket;
currentCharacter = ioModule.NextCh();
break;
case ']':
CurrentSymbol = SymbolEnum.RightSquareBracket;
currentCharacter = ioModule.NextCh();
break;
case '{':
CurrentSymbol = SymbolEnum.LeftCurlyBracket;
currentCharacter = ioModule.NextCh();
break;
case '}':
CurrentSymbol = SymbolEnum.RightCurlyBracket;
currentCharacter = ioModule.NextCh();
break;
case '.':
currentCharacter = ioModule.NextCh();
if (currentCharacter.Value == '.')
{
CurrentSymbol = SymbolEnum.TwoDots;
currentCharacter = ioModule.NextCh();
}
else
{
CurrentSymbol = SymbolEnum.Dot;
}
break;
case ',':
CurrentSymbol = SymbolEnum.Comma;
currentCharacter = ioModule.NextCh();
break;
case '^':
CurrentSymbol = SymbolEnum.Arrow;
currentCharacter = ioModule.NextCh();
break;
case ';':
CurrentSymbol = SymbolEnum.Semicolon;
currentCharacter = ioModule.NextCh();
break;
default:
Error = ioModule.AddError(6, CurrentLineNumber, CurrentPositionInLine);
break;
}
}
}
