parse method
Implementation
@override
Tuple1<int>? parse(ParseInput<String> input, ParseState state) {
final c = input.ch;
if (c >= 0x30 && c <= 0x39) {
input.pos++;
return Tuple1(c);
}
state.fail(error, input.pos);
}
@override
Tuple1<int>? parse(ParseInput<String> input, ParseState state) {
final c = input.ch;
if (c >= 0x30 && c <= 0x39) {
input.pos++;
return Tuple1(c);
}
state.fail(error, input.pos);
}