private static Token ReadSymbol(LocatedTextReaderWrapper input)
{
var curToken = "";
while(input.Peek() >= 0) {
char nextCharacter = (char)input.Peek();
if(!IsSymbolChar(nextCharacter)) {
break;
}
string newToken = curToken + nextCharacter;
if(!IsSymbolStart(newToken)) {
break;
}
curToken = newToken;
input.Read(); // Discard.
}
return new Token(TokenType.Symbol, curToken);
}
private static Token ReadString(LocatedTextReaderWrapper input)
{
var str = new StringBuilder();
input.Read(); // Consume ".
while(true) {
int rawChar = input.Read();
if(rawChar < 0) {
throw new MissingDataException("End-of-string terminator", input.Location);
}
char nextCharacter = (char)rawChar;
if(nextCharacter == '"') {
break;
}
if(nextCharacter == '\\') {
nextCharacter = ReadEscapeCode(input);
}
str.Append(nextCharacter);
}
return new Token(TokenType.String, str.ToString());
}
private static Token ReadIdentifier(LocatedTextReaderWrapper input)
{
var token = new StringBuilder();
while(input.Peek() >= 0) {
char nextCharacter = (char)input.Peek();
if(!IsIdentifierChar(nextCharacter)) {
break;
}
token.Append(nextCharacter);
input.Read(); // Discard.
}
return new Token(TokenType.Identifier, token.ToString());
}
private static Token ReadNumber(LocatedTextReaderWrapper input)
{
var startLocation = input.Location.Clone();
var numberString = new StringBuilder();
while(IsNumberChar((char)input.Peek())) {
numberString.Append((char)input.Read());
}
double number;
if(!double.TryParse(numberString.ToString(), NumberStyles.AllowDecimalPoint | NumberStyles.AllowLeadingSign, Parser.DefaultCulture, out number)) {
throw new BadDataException("Number", startLocation);
}
return new Token(TokenType.Number, number);
}
private static char ReadEscapeCode(LocatedTextReaderWrapper input)
{
int nextCharacter = input.Read();
if(nextCharacter < 0) {
throw new MissingDataException("Code following \\", input.Location);
}
switch((char)nextCharacter) {
case 'n':
return '\n';
case 't':
return '\t';
case 'r':
return '\r';
case '\\':
return '\\';
case '"':
return '"';
default:
var e = new BadDataException("Unknown escape character", input.Location);
e.Data["character"] = (char)nextCharacter;
throw e;
}
}