public Token Scan()
{
while (true)
{
_peak = (char)Console.Read();
if (_peak == ' ' || _peak == '\t')
{
continue;
}
else if (_peak == '\n')
{
Line = Line + 1;
}
else
{
break;
}
}
if (char.IsDigit(_peak))
{
int v = 0;
do
{
v = 10 * v + (int)char.GetNumericValue(_peak);
_peak = (char)Console.Read();
} while (char.IsDigit(_peak));
return(new NumberToken(v));
}
if (char.IsLetter(_peak))
{
var b = new StringBuilder();
do
{
b.Append(_peak);
_peak = (char)Console.Read();
} while (char.IsLetterOrDigit(_peak));
var s = b.ToString();
var w = (WordToken)_words[s];
if (w != null)
{
return(w);
}
w = new WordToken(Tags.ID, s);
_words.Add(s, w);
return(w);
}
var t = new Token(_peak);
_peak = ' ';
return(t);
}
private void Reserve(WordToken word)
{
_words.Add(word.Tag, word);
}