Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!fernwood!lia!jgro
From: jgro@lia (Jeremy Grodberg)
Newsgroups: comp.lang.c++
Subject: Re: How to define a List class
Message-ID: <1991Jun20.220432.955@lia>
Date: 20 Jun 91 22:04:32 GMT
References: <350001@hpgnd.grenoble.hp.com> <28539115.4D91@tct.com> <1991Jun11.172115.2804@intellistor.com> <285E7568.4E93@tct.com> <1991Jun19.151546.15605@intellistor.com>
Reply-To: jgro@lia.com (Jeremy Grodberg)
Lines: 40

In article <1991Jun19.151546.15605@intellistor.com> wicklund@intellistor.com (Tom Wicklund) writes:
>In <285E7568.4E93@tct.com> chip@tct.com (Chip Salzenberg) writes:
>
>>According to wicklund@intellistor.com (Tom Wicklund):
>>>I think what's desired (and should be implementable) is a way to
>>>define a list class using templates and have the compiler be smart
>>>enough to create a single implementation for the list methods.
>
>>That can already be done with templates.  Create a ListBase class with
>>all the interesting code.  Then create List<class T> template in which
>>all member functions are inline.  Presto.
>
>But the challenge is to do this without requiring inline functions.  A
>list class shouldn't need to know anything about the objects which are
>being placed in the list except for size (depending on implementation)
>and the compiler can easily pass the size to a method if required.
>Unfortunately it requires better compiler technology than most current
>compilers.

This is not entirely true.  The list class needs to know the type of
object that is being added and extracted.  Templates allow for 
compile-time checking, whereas other methods require run-time checking.
Yes, it is a little inelegant to duplicate the code, but it is not
much code to duplicate.  

We aren't using computers with 4 K of core and which execute a few 
thousand instructions per second anymore.  I'm getting tired of people
complaining about implementations which waste a few hundred bytes of 
code without ackowledging the benefit of increased reliability and
decreased programming time.  In many cases, templates even produce more
time-efficient code.  Don't get me wrong; I'd love to have a solution
which provides all the benefits of templates without the extra code,
but in the mean time, I think the cost is well worth it.




-- 
Jeremy Grodberg      "Show me a new widget that's bug-free, and I'll show
jgro@lia.com         you something that's been through several releases."