[lcnPylGDnU4H9OF]

I dunno about those rules; there are exceptions. Yttrium. Yggdrasil. Probably others, but those from off the top of my head.

I think the best way to define when Y is a vowel is when it's not a consonant. Basically, if you make the sound that Y represents in the word "yes", it's a consonant. Otherwise, it's a vowel. (At least, no exceptions come to mind.)

[DougN7]

Wow, how would you code that?!

[lcnPylGDnU4H9OF]

Heh, good question. I’d probably use a heuristic like what’s discussed in this thread and hope that it works. :D