void reserve(Word w)
{
words.Add(w.lexeme, w);
}
public Token scan()
{
for (; ; readch())
{
if (peek == ' ' || peek == '\t')
continue;
else if (peek == '\n')
line++;
else
break;
}
if (peek == '/')
{
readch();
if (peek == '/')
{
while (peek != '\n')
readch();
line++;
}
else if (peek == '*')
{
readch();
while (true)
{
if (peek == '*')
{
readch();
if (peek == '/')
break;
}
else if (peek == 65535)
return new Word("_THE_END_", Tag._THE_END_);
else
readch();
}
}
else
return new Token('/');
}
/* switch (peek)
{
case '&':
if (readch('&')) return Word.and; else return new Token('&');
case '|':
if (readch('|')) return Word.or; else return new Token('|');
case '=':
if (readch('=')) return Word.eq; else return new Token('=');
case '!':
if (readch('=')) return Word.ne; else return new Token('!');
case '<':
if (readch('=')) return Word.le; else return new Token('<');
case '>':
if (readch('=')) return Word.ge; else return new Token('>');
}
*/
if (Char.IsDigit(peek))
{
int v = 0;
do
{
v = 10 * v + peek;
readch();
} while (Char.IsDigit(peek));
if (peek != '.') return new Num(v);
double x = v;
double d = 10.0;
for (; ; )
{
readch();
if (!Char.IsDigit(peek))
break;
x = x + peek / d;
d *= 10;
}
return new Real(x);
}
if (Char.IsLetter(peek) || peek == '.')
{
StringBuilder b = new StringBuilder();
do
{
if (peek == '.')
b.Append('_');
else
b.Append(peek);
readch();
} while (Char.IsLetter(peek) || peek == '_');
string s = b.ToString();
Word w = (Word)words[s];
if (w != null) return w;
w = new Word(s, Tag.ID);
words.Add(s, w);
return w;
}
Token token = new Token(peek);
peek = ' ';
return token;
}