footnote method
The number footnote label displays as, or null when it has none.
Footnotes are numbered in the order they are first referenced, as GitHub numbers them, so the text reads ¹ ² ³ whatever order the definitions are written in. A footnote nothing refers to has no number, and is not shown.
Implementation
int? footnote(String label) {
final lookups = _lookups;
if (lookups == null && _footnoteDefinitions.isEmpty) {
return null;
}
final key = normalizeLabel(label);
lookups?.add('f:$key');
return _footnotes[key];
}