Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!uunet!amara!lokkur!scs
From: scs@lokkur.dexter.mi.us (Steve Simmons)
Newsgroups: comp.mail.elm
Subject: Re: System aliases
Keywords: ELM, aliases.
Message-ID: <1989Jul30.013125.7407@lokkur.dexter.mi.us>
Date: 30 Jul 89 01:31:25 GMT
References: <509@wubios.wustl.edu> <177@van-bc.UUCP> <1023@isaak.UUCP> <203@van-bc.UUCP>
Organization: Inland Sea
Lines: 41

skl@van-bc.UUCP (Samuel Lam) writes:
>In article <1023@isaak.UUCP>, woerz@isaak.UUCP (Dieter Woerz) wrote:
>>In article <177@van-bc.UUCP> I wrote:
>>>In article <509@wubios.wustl.edu>, phil@wubios.UUCP (J. Philip Miller) wrote:
>>>>[about system aliases being replaced by the senders's personal
>>>> aliases with the same name]
>>>[response]
>>There is still a problem. Asume you have the following system alias
>>file:
>>    allusers =  All users of this host  =   a, b, c, d, e, f
>>and the sender of the message has the following in his personal
>>aliases file:
>>    c = ... =   c@x.y.z
>>Then the c@x.y.z get the message that should have reached c on the
>>local machine.

>If that's the case, then shouldn't the current behaviour of this be
>consider broken?  My argument here is that when the system administrator
>makes up the system aliases file, there would be no way for him to
>predict how the system aliases would later expand IF each user's private
>aliases file is also taken into consideration during the later expansion.
>If there is no way to predict how a system alias is going to expand, then
>what good is it to have system aliases (that's unpredictable).  (Under
>what circumstances would the current behaviour be actually considered
>useful?)

Glad I didn't jump into the discussion earlier -- the above paragraph
lays most of the goundwork.

The issue is much broader than elm.  Exactly the same problems occur
with any mail user agent which allows the user to define his own
aliases.  Any time there is a heirarchy of aliases, it is possible for
lower level aliases to "mask off" upper level ones.  Pretty similar to
programming languages which allow nesting.

This is a general and unsolvable problem with aliases.  Speaking as a
member of the development group (but not for it), I would not change
the feature.
-- 
: Steve Simmons         ...sharkey!lokkur!scs     scs@lokkur.dexter.mi.us :
:                 UNIX -- The OS/360 of the 21st Century                  :