> You realize that in prolog mode the TAB key is not bound to
> self-insert-command?  It runs prolog-indent-line, which inserts as
> much space as it feels like (according to some indent algorithm).
Hmm.

> Now why prolog mode and you disagree on the indenting is another
> question.  In general emacs' syntax parser is very weak in correctly
> identifying whether you are in a string or not.  Perl mode tends to
> get totally confused with things along the lines of:
>
> 	    \"
>
> 	    (or)
>
> 	    # 'tis a random comment
>
> 	    (these are from memory, so I may have the details slightly
> 	    wrong.)
>
> Could the same sort of thing be happening to you in prolog mode?  Does
> TAB still work at the top of the buffer, but stop somewhere lower
> down?

No, the Tab isn't working at all, unless I do a manual tab for an indent and 
it realises that it's supposed to indent.
It seems that it only tabs to where it thinks it should indent.

I have had the situation where it won't work after a certain point in other 
modes. I guess that's to do with the parser losing the plot slightly. It 
makes sense from what I know about how Emacs works (which isn't a great deal).

David