private Token ReadString()
{
StartRead();
char startSymbol = LA(0);
Consume(); // consume first string character
while (true)
{
char ch = LA(0);
if (ch == startSymbol)
{
Consume();
string tokenData = data.Substring(savePos + 1, pos - savePos - 2);
return(CreateToken(TokenType.String, tokenData));
}
else if (ch == '\\')
{
if (LA(1) == 'n' || LA(1) == 'r' || LA(1) == '\'' || LA(1) == '"')
{
// string escape
Consume(2);
continue;
}
else
{
ParserException ex = new ParserException("Unknown escape sequence. Supported escapes: \\n, \\r, \\\", \\'",
line, column, pos, 2);
ex.Data["code"] = LEXER_ERROR_UNKNOWN_ESCAPE;
throw ex;
}
}
else if (ch == EOF)
{
ParserException ex = new ParserException("Unterminated string constant", saveLine, saveColumn,
savePos, pos - savePos);
ex.Data["code"] = LEXER_ERROR_UNTERMINATED_STRING;
throw ex;
}
else
{
// consume next string symbol
Consume();
}
}
}
private Token ReadExpression()
{
StartRead();
start:
char ch = LA(0);
switch (ch)
{
case EOF:
return(CreateToken(TokenType.EOF));
case ':':
Consume();
return(CreateToken(TokenType.Colon));
case '.':
Consume();
return(CreateToken(TokenType.Dot));
case ',':
Consume();
return(CreateToken(TokenType.Comma));
case '(':
Consume();
return(CreateToken(TokenType.LParen));
case ')':
Consume();
return(CreateToken(TokenType.RParen));
case '[':
Consume();
return(CreateToken(TokenType.LBracket));
case ']':
Consume();
return(CreateToken(TokenType.RBracket));
case '#': // end of expression
Consume();
printStart = false;
expressionBody = false;
return(Next());
case '+':
Consume();
return(CreateToken(TokenType.Plus));
case '-':
Consume();
return(CreateToken(TokenType.Minus));
case '*':
Consume();
return(CreateToken(TokenType.Mult));
case '/':
Consume();
return(CreateToken(TokenType.Div));
case '%':
Consume();
return(CreateToken(TokenType.Mod));
case '<':
if (LA(1) == '=')
{
Consume(2);
return(CreateToken(TokenType.LessOrEqual));
}
else
{
Consume();
return(CreateToken(TokenType.Less));
}
case '>':
if (LA(1) == '=')
{
Consume(2);
return(CreateToken(TokenType.GreaterOrEqual));
}
else
{
Consume();
return(CreateToken(TokenType.Greater));
}
case '=':
if (LA(1) == '=')
{
Consume(2);
return(CreateToken(TokenType.Equal));
}
else
{
Consume();
return(CreateToken(TokenType.Assign));
}
case '!':
if (LA(1) == '=')
{
Consume(2);
return(CreateToken(TokenType.NotEqual));
}
else
{
Consume();
return(CreateToken(TokenType.Not));
}
case '|':
if (LA(1) == '|')
{
Consume(2);
return(CreateToken(TokenType.Or));
}
else
{
Consume();
return(CreateToken(TokenType.BinOr));
}
case '&':
if (LA(1) == '&')
{
Consume(2);
return(CreateToken(TokenType.And));
}
else
{
Consume();
return(CreateToken(TokenType.BinAnd));
}
case ' ':
case '\t':
case '\r':
case '\n':
ReadWhitespace();
goto start;
case '"':
case '\'':
return(ReadString());
default:
if (Char.IsNumber(ch))
{
return(ReadNumber());
}
else if (Char.IsLetter(ch) || ch == '_')
{
return(ReadIdentifier());
}
else
{
string symbol = ch.ToString();
ParserException ex = new ParserException(String.Format("Unexpected symbol: '{0}'", symbol),
saveLine, saveColumn, pos, 1);
ex.Data["code"] = LEXER_ERROR_UNEXPECTED_SYMBOL;
ex.Data["symbol"] = symbol;
throw ex;
}
}
}
private Token ReadTagBody()
{
StartRead();
start:
char ch = LA(0);
switch (ch)
{
case EOF:
return(CreateToken(TokenType.EOF));
case '>':
Consume();
tagBody = false;
return(Next());
case '=':
Consume();
return(CreateToken(TokenType.Assign));
case ' ':
case '\t':
case '\r':
case '\n':
ReadWhitespace();
goto start;
case '"':
if (attributeBody)
{
// end of attribute
Consume(); // eat "
attributeBody = false;
}
else
{
// start of attribute
attributeBody = true;
if (LA(1) == '#')
{
Consume(2); // eat "#
expressionBody = true;
return(Next());
}
else
{
attributeBody = false;
if (Char.IsNumber(LA(1)))
{
Consume(); // eat "
Token num = ReadNumber();
Consume(); // eat "
return(num);
}
else
{
return(ReadString());
}
}
}
goto start;
case '\'':
return(ReadString());
default:
if (ch == '/' && LA(1) == '>')
{
// "empty" tag
Consume(2);
tagBody = false;
return(CreateToken(TokenType.EmptyTag));
}
else if (Char.IsLetter(ch) || ch == '_')
{
return(ReadAttribute());
}
else
{
string symbol = ch.ToString();
ParserException ex = new ParserException(String.Format("Unexpected symbol: '{0}'", symbol),
saveLine, saveColumn, pos, 1);
ex.Data["code"] = LEXER_ERROR_UNEXPECTED_SYMBOL;
ex.Data["symbol"] = symbol;
throw ex;
}
}
}
