public Token nextToken()
{
while (input[pos] == ' ')
pos++;
int startPos = pos;
if (isAChar(input[pos]))
{
pos++;
while (isAChar(input[pos]) || isANumber(input[pos]))
pos++;
string tk = input.Substring(startPos, pos - startPos);
WordToken w = (WordToken)words[tk];
if (w != null)
return w;
else
{
WordToken t = new WordToken(TokenType.IDE, tk);
words.Add(tk, t);
return t;
}
}
else switch (input[pos])
{
case '(':
pos++;
return Token.openb;
case ')':
pos++;
return Token.closeb;
case ',':
pos++;
return Token.comma;
case '=':
pos++;
return Token.equals;
case '\0':
return Token.eof;
default:
Error("Parsing error: " + input[pos] + " is a invalid char");
return null;
}
}
void reserve(WordToken w)
{
words.Add(w.Lexeme, w);
}