Hiding text

[thorne]

Hello, i am wanting to have something akin to enriched mode that will
allow me to type some text marked up with underscores (or similar) and
in the buffer it will not show the underscores but will show the
enclosed text underlined.

I could use enriched mode for this, but i don't want the buffer saved
with the text/enriched header or with all its extra linebreaks.
Basically, what i am looking for is a wysiwyg treatment of
underlining, but such that i can easily go through later and do a
replace-regexp and turn it into some other kind of markup.

I think maybe gnus does something like this with underscores, but i'm
not sure.

I tried doing this with font-lock, and was able to do everything i
wanted, except that the underscores--which i make invisible--leave a
blank space instead of completely disappearing.

So, maybe a more focused version of my question would be: is there a
way to selectively hide strings of text in a buffer such that they
still exist if you kill the region they are in and yank it somewhere
else?  I've read references to `folding' and `outlining' and
`narrowing' and so-forth, but i'm not sure where to start.

-- 
þ    theron tlax    þ