parse static method
Implementation
static ETEntityReference? parse(String ref) {
if (ref.length < 3) return null;
ref = ref.trim();
var idx = ref.indexOf('#');
if (idx < 1) return null;
var typePart = ref.substring(0, idx);
var idPart = ref.substring(idx + 1);
if (!matchesType(typePart, 0, typePart.length)) return null;
if (!matchesID(idPart, 0, idPart.length)) return null;
var id = parseInt(idPart)!;
return ETEntityReference(typePart, id);
}