Indentation in derived modes?

[Jesse Sheidlower]

I'm relatively new to the actual writing of Emacs Lisp, but
I'd like to figure out whether it would be possible [i.e. for
me] to get indentation working for a derived mode.

I'm looking at various templating systems for embedding some
kind of programming code within HTML, and would like Emacs to
handle this as best as possible. It seems that basing it on an
HTML-type mode, like psgml-mode (which seems only to indent if
there's a DTD included, which may not always be the case if
you're using templates) or html-helper-mode (does that indent,
for that matter? I haven't used it), would be the way to start,
and then adding to it some functionality for indenting the
template's statements. Is that possible, or would I have to
redo the entire indentation code to accommodate the possibility
of embedded non-HTML statements? Is this a particularly difficult
programming task?

Any pointers to tutorials for writing such code would also
be appreciated! There wasn't anything on it in a few of the
things I've looked at already.

Thanks very much.

Jesse Sheidlower