private VisualBasicAstToken ReadStringToken()
{
var startLocation = Location;
var startCharacter = Read();
TextRange range;
bool escaped = false;
string stringToken = startCharacter + ReadCharacters(x =>
{
return x == startCharacter;
// TOOD: c suffix and double quotes inside string.
}, out range);
char character;
if (Peek(out character) && character == startCharacter)
stringToken += Read();
var endLocation = Location;
var astToken = new VisualBasicAstToken(LITERAL, stringToken, new TextRange(startLocation, endLocation));
astToken.UserData["InterpretedValue"] = VisualBasicLanguage.Instance.StringFormatter.EvaluateFormattedString(stringToken);
return astToken;
}
protected override AstToken ReadNextToken()
{
while (true)
{
if (!MoveToNextToken())
return new VisualBasicAstToken(EOF, string.Empty, new TextRange(Location, Location));
char currentChar;
Peek(out currentChar);
VisualBasicAstToken token;
if (currentChar == '\'')
{
var node = ReadSingleLineComment();
token = node as VisualBasicAstToken;
if (token == null)
{
SpecialBag.SpecialNodes.Add(node);
continue;
}
}
else if (char.IsDigit(currentChar))
{
token = ReadNumberToken();
}
else if (IsWordElement(currentChar))
{
token = ReadWordToken();
VisualBasicAstTokenCode keywordCode;
if (VisualBasicAstToken.KeywordMapping.TryGetValue(token.Value, out keywordCode))
{
token.Code = keywordCode;
switch (keywordCode)
{
case TRUE:
token.UserData["InterpretedValue"] = true;
break;
case FALSE:
token.UserData["InterpretedValue"] = false;
break;
}
}
}
else if (currentChar == '\'' || currentChar == '"')
{
token = ReadStringToken();
}
else
{
var start = Location;
StartReadBuffer();
var code = TokenizeCurrentSymbol();
var end = Location;
token = new VisualBasicAstToken(code, EndReadBuffer().ToString(), new TextRange(start, end));
}
return token;
}
}
protected VisualBasicAstToken ReadNumberToken()
{
TextRange range;
bool hasSuffix = false;
bool hasDecimalSpecifier = false;
string token = ReadCharacters(x =>
{
if (char.IsLetter(x))
{
hasSuffix = true;
return true;
}
if (char.IsDigit(x))
return !hasSuffix;
if (x == '.')
{
if (hasDecimalSpecifier)
throw new Exception("Too many decimal specifiers in number.");
hasDecimalSpecifier = true;
return true;
}
return false;
}, out range);
var astToken = new VisualBasicAstToken(LITERAL, token, range);
astToken.UserData["InterpretedValue"] = VisualBasicLanguage.Instance.NumberFormatter.EvaluateFormattedNumber(token);
return astToken;
}