Figuring out what type of text is on the clipboard, and ascii filtering

[Dr. Hawkins]

I'm trying to figure out how to filter potentially unknown source pasted
text into plain 7 bit ASCII.

Working on a mac, for example, the incoming text might be:

   - Honest ASCII
   - Apple 8 bit extended characters
   - MS characters from a Word document created on MS
   - Who knows what coming from a virtual machine
   - HTML clipped from a browser
   - "moronized" text pasted from MS word to a website, then clipped by a
   user
   - who knows what else?


I know I need to intercept paste, but I need to reliably take out any of
the above that SQLite doesn't like.  Fortunately, there is no prospect of
dealing with other than English, or out of ASCII set characters--but they
might come in anyway, such as curly quotes, or something from another
character set.

How can I inspect what is there to figure out how to filter it?

And, in a similar vein, I need to protect agains who-knows-what that the
host OS allows to be entered at the keyboard . . .

-- 
Dr. Richard E. Hawkins, Esq.
(702) 508-8462