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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: newbie Q: storage management
Date: 1997/05/09
Message-ID: <dewar.863177058@merv>#1/1
X-Deja-AN: 240566736
References: <5k5hif$7r5@bcrkh13.bnr.ca> <dewar.862662935@merv>
 	<336E15A4.167E@magellan.bgm.link.com> <dewar.862915787@merv>
 	<E9rMAn.93B@world.std.com> <JSA.97May7204713@alexandria>
Organization: New York University
Newsgroups: comp.lang.ada
Date: 1997-05-09T00:00:00+00:00
List-Id: <comp.lang.ada>


Jon asks

<<Again, this makes good sense - at least up to a point.  But as you say
 "in general".  Why even have generics?>>
   
  Because there was consensus agreement that this was a critical feature

<<Why have tasking?>>

  Because there was consensus agreement that this was a critical feature

<<Why have packages?>>

  Because there was consensus agreement that this was a critical feature

  The whole point is that no such consensus existed for the idea of GC, not
  even a noticable minority opinion, hence it was just not on the radar
  screen. And this was not because it was ignored, it was because the great
  majority actively opposed the idea, and there was no significant input
  from anyone to the contrary (look for example through the revision
  requests ...)

<<How about the DSA?  How many Ada83 vendors were falling over
  themselves trying to implement various distributed object scenarios??>>

  A fair question, the DSA only *just* survived the process, and the
  discussion was exactly along the lines of wondering whether we were
  sure that we knew enough to specify the approach. However, unlike the
  case with GC, the clear majority *did* feel that this was a critical
  feature which should be addressed. The discussion was not over whether
  the language should have such features, but whether the formulation
  was correct. We did not even get that far with GC.

<<True enough.  One obvious way out of this for Ada is the generalized
version of what Robert called out as a "compromise": a subsystem of
generics which offered several variants.  A single global GC handling
all dynamic memory issues isn't really needed.  In fact, this is an
area where Ada could do something a little different by offering the
ability to have multiple collectors per application targetting the
specific needs of specific types (or classes of types).  This is the
sort of thing that I've been working on.>>

  Actually, I prefer an approach with single global GC handling, but in
  any case, clearly the constructive thing at this stage is to produce
  sample implementations and encourage users to use them!