removing duplicate from history by default [was Re: avoid duplicates in history]

[Dan Nicolaescu]

Let's reopen the discussion started with the message here:

http://lists.gnu.org/archive/html/emacs-devel/2004-06/msg00021.html

I would like to prepare a patch that can be checked in. 

There was one question left, if removing duplicates from history
should be turned on by default. 
IMHO duplicates should be removed from history by default, most users
are more interested in the unique data present in history. If an exact
sequence of events is desired M-x list-command-history can do that.

[I reformated the last message from Stephan in that thread  to make it
clear who said what]:

Dan> How about the default? Should this be turned on by default? 
Juri>     It seems reasonable to turn it on by default.

RMS> Absolutely not!  It would be a great surprise, and it would mean
RMS> you could not look around at your error messages without changing
RMS> other buffers on the screen.

Stephan> Huh?  I don't understand why removing duplicates from the history
Stephan> would ever have any such effect.
Stephan> Could you explain what use case you're thinking of ?

Thanks
                --dan