public object TryResolveSymbol(SymbolToken pSymbolToken)
{
if (vars.ContainsKey(pSymbolToken.value)) {
//Console.WriteLine("Resolved " + pSymbolToken + " in scope " + name);
return vars[pSymbolToken.value];
} else if (enclosingScope != null) {
//Console.WriteLine("Can't find " + pSymbolToken + " in scope " + name + ", looking in enclosing scope: " + enclosingScope.name);
return enclosingScope.TryResolveSymbol (pSymbolToken);
} else {
throw new Exception ("Can't resolve symbol " + pSymbolToken + " at line " + pSymbolToken.line + " and position " + pSymbolToken.position);
}
}
public List<Token> Read(string pString)
{
_readPosition = 0;
_stringToRead = pString;
_tokens = new List<Token> ();
while(MoreToRead()) {
char c = ReadCurrentChar ();
Token newToken = null;
int lineBeforeReading = _lineNr;
int positionBeforeReading = _positionOnLine;
if (c == '\n') {
_positionOnLine = 1;
_lineNr++;
Step ();
}
else if (IsWhitespace (c)) {
Step ();
} else if (c == '(') {
newToken = new Token (TokenType.LEFT_PAREN);
Step ();
} else if (c == ')') {
newToken = new Token(TokenType.RIGHT_PAREN);
Step ();
} else if (c == '[') {
newToken = new Token(TokenType.LEFT_BRACKET);
Step ();
} else if (c == ']') {
newToken = new Token(TokenType.RIGHT_BRACKET);
Step ();
} else if (c == '\'') {
newToken = new Token(TokenType.TICK);
Step ();
} else if (c == ';') {
while (MoreToRead() && ReadCurrentChar() != '\n') {
Step ();
}
} else if (c == '\"') {
newToken = new StringToken(ReadString ());
} else if (c == '&') {
newToken = new ReservedToken(TokenType.AMPERSAND);
Step ();
} else if (c == '.') {
newToken = new SymbolToken(c.ToString());
Step ();
} else if(IsChar (c)) {
string text = ReadText ();
if(IsNumber(text)) {
newToken = new FloatToken(Convert.ToSingle(text));
} else if (text == "def") {
newToken = new ReservedToken(TokenType.DEF);
} else if (text == "fn") {
newToken = new ReservedToken(TokenType.FN);
} else if (text == "let") {
newToken = new ReservedToken(TokenType.LET);
} else if (text == "if") {
newToken = new ReservedToken(TokenType.IF);
} else if (text == "defmacro") {
newToken = new ReservedToken(TokenType.DEFMACRO);
} else if (text == "quote") {
newToken = new ReservedToken(TokenType.QUOTE);
} else if (text == "set!") {
newToken = new ReservedToken(TokenType.SET);
} else if (text == "null") {
newToken = new NullToken();
} else if (text == "true") {
newToken = new BoolToken(true);
} else if (text == "false") {
newToken = new BoolToken(false);
} else {
newToken = new SymbolToken(text);
}
}
else {
throw new Exception ("Can't understand char '" + c + "'" + " at line " + _lineNr + " and position " + _positionOnLine);
}
if(newToken != null) {
newToken.line = lineBeforeReading;
newToken.position = positionBeforeReading;
_tokens.Add (newToken);
}
}
return _tokens;
}