filterForChannel method
Implementation
List<Token>? filterForChannel(int from, int to, int channel) {
final hidden = <Token>[];
for (var i = from; i <= to; i++) {
final t = tokens[i];
if (channel == -1) {
if (t.channel != Lexer.DEFAULT_TOKEN_CHANNEL) hidden.add(t);
} else {
if (t.channel == channel) hidden.add(t);
}
}
if (hidden.isEmpty) return null;
return hidden;
}