Universally Unique Lexicographically Sortable Identifier

> Uses Crockford's base32 for better efficiency and readability (5 bits per character)

From what I can tell, this is the alphabet:

  0123456789ABCDEFGHJKMNPQRSTVWXYZ

Is there any reason why Crockford's alphabet hasn't been rolled into an RFC that supersedes RFC 4648 if it's more efficient and readable?

RFC 4648 specifies [0-9a-v] (base32hex) and [a-z2-7] (base32).

A long uppercase trash is hardly considered a recognizable identifier. Remember, it needs to be identifiable. IMHO UUID's are more identifiable with its 4 words.

Uniqueness is usually guaranteed by a symbol table, and the op is gensym().