parse method
Implementation
@override
Node parse(BlockParser parser) {
var lines = <String>[];
String? tag;
while (!parser.isDone) {
var match = _setextPattern.firstMatch(parser.current);
if (match == null) {
// More text.
lines.add(parser.current);
parser.advance();
continue;
} else {
// The underline.
tag = (match[1]![0] == '=') ? 'h1' : 'h2';
parser.advance();
break;
}
}
var contents = UnparsedContent(lines.join('\n').trimRight());
return Element(tag!, [contents]);
}