can vim do this?

[Lev Lvovsky]

I recently started work at a company where the predominant text  
editor happens to be emacs.  I've been using vim for a while now,  
though only recently started getting into the more advanced  
functionality beyond simple editing (highlighting, folding, tags  
etc...).  Watching one of my co-workers with emacs is pretty fun, as  
he does things fairly quickly - I asked him what his most common  
emacs actions were, to see how I could do them in vim:

* autocomplete - say that I've declared a constant variable in Perl  
named MY_CONSTANT, later, to have the editor fill it in, I type in  
MY_, and some other key-stroke, and "CONSTANT" gets typed in for you

* goto when compiling - when compiling with make for example, and  
there is a problem in the code identified by a line, can vim somehow  
know to go to that line?  this would be especially useful with 'make'

* rectangular cut/pastes - if I have a column (multi-row) of text  
that I'd like to paste on several lines, can I do this without a regex?

* ctags variable name references - assuming I'm using ctags, how can  
I replace the name of a variable throughout my code base?

* regional undo - can I select a region, and perform an undo for all  
of the changes only in that region?

* cvs/diff mode - what support does vim offer for these two apps,  
internal to the editor.

I'll be glad to RTFM for all of these things, however I don't know  
where to look them up - any pointers would be appreciated!

thanks,
-lev