From: billwolf@hubcap.clemson.edu (William Thomas Wolfe,2847,)
Subject: Re: Garbage Collection
Date: 11 Dec 88 19:11:52 GMT [thread overview]
Message-ID: <3832@hubcap.UUCP> (raw)
In-Reply-To: 124000026@inmet
From article <124000026@inmet>, by ron@inmet.UUCP:
>
> Garbage collection certainly does not come for free, but it is extremely
> useful. It frees the programmer from the need to repeatedly write
> sophisticated ADT deallocate routines and to deal with the potentially
> massive book-keeping requirements for determining whether an object is in
> fact garbage. In general, lack of GC forces a programmer to invest a lot of
> effort addressing issues that are not fundamentally related to the problem
> domain. My experience has also shown that problems of "slow heap leakage"
> are among the hardest errors to correct.
"Repeatedly" write sophisticated ADT deallocate routines?? The basic
idea is to write an ADT once and use it forever (i.e., until the next
language modification :-) ); where does "repeatedly" come in?
Dealing with the details of allocation requires as much effort as
dealing with deallocation. Perhaps you would say that any maintenance
of the structure used to represent your ADT is not fundamentally
related to the problem domain. If so, I will have to disagree.
ADTs, and computer programs in general, are characterized by both
time complexity and space complexity. Making the tradeoffs between
these forms of complexity is one of the most fundamental questions
a programmer must deal with. This is the topic of much, if not most,
of the literature regarding ADTs.
Also, I disagree with the claim that a lot of effort is involved;
in my experience, DESTROY routines are among the easiest to code.
Usually, the ADT is defined recursively, lending itself to a very
easy recursive destruction procedure; after that, just destroy
any sub-ADTs in your descriptor, and from there it only takes one
line of code to blow away the descriptor. About the hardest part
of the whole process is the tedium of looking through to see what
fields are user-defined sub-ADTs, since they have to be explicitly
destroyed due to Ada's lack of integration between UNCHECKED_DEALLOCATION
and user-defined DESTROY procedures.
Bill Wolfe
wtwolfe@hubcap.clemson.edu
next prev parent reply other threads:[~1988-12-11 19:11 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
1988-12-03 22:53 Collective response to := messages Erland Sommarskog
1988-12-04 20:41 ` William Thomas Wolfe,2847,
1988-12-05 5:47 ` Richard A. O'Keefe
1988-12-05 12:45 ` William Thomas Wolfe,2847,
1988-12-06 1:54 ` Richard A. O'Keefe
1988-12-06 20:43 ` William Thomas Wolfe,2847,
1988-12-07 15:22 ` Collective response to := messa ron
1988-12-11 19:11 ` William Thomas Wolfe,2847, [this message]
1988-12-12 5:29 ` Garbage Collection John Gateley
1988-12-12 18:19 ` William Thomas Wolfe,2847,
1988-12-13 1:02 ` Alexander Klaiber
1988-12-13 18:37 ` William Thomas Wolfe,2847,
1988-12-13 23:36 ` Alexander Klaiber
1988-12-14 3:26 ` William Thomas Wolfe,2847,
1988-12-14 17:16 ` Stephe Leake
1988-12-15 14:43 ` Thomas P. Morris
1988-12-14 23:30 ` John Gateley
1988-12-15 19:25 ` William Thomas Wolfe,2847,
1988-12-19 16:12 ` John Gateley
1988-12-20 19:34 ` Bill Wolfe
1988-12-16 0:49 ` Keys are references, too (was Re: Garbage Collection) Badger BA 64810
1988-12-18 18:42 ` William Thomas Wolfe,2847,
1988-12-13 20:22 ` Garbage Collection William Thomas Wolfe,2847,
1988-12-14 6:40 ` Richard A. O'Keefe
1988-12-14 17:43 ` William Thomas Wolfe,2847,
1989-01-02 17:51 ` ryer
1989-01-05 8:31 ` William Thomas Wolfe,2847,
1989-01-06 16:58 ` ryer
1989-01-08 19:24 ` William Thomas Wolfe,2847,
-- strict thread matches above, loose matches on Subject: below --
1999-08-18 0:00 garbage collection Ronald Ayoub
1999-08-18 0:00 ` tmoran
1999-08-18 0:00 ` Keith Thompson
1999-08-19 0:00 ` Tucker Taft
1999-08-19 0:00 ` Robert Dewar
1999-08-19 0:00 ` Robert Dewar
1999-08-20 0:00 ` tmoran
1999-08-20 0:00 ` Keith Thompson
1999-08-20 0:00 ` Matthew Heaney
1999-08-20 0:00 ` Keith Thompson
1999-08-21 0:00 ` Matthew Heaney
1999-08-21 0:00 ` Robert Dewar
1999-08-21 0:00 ` Matthew Heaney
1999-08-21 0:00 ` Robert Dewar
1999-08-21 0:00 ` Brian Rogoff
1999-08-21 0:00 ` Robert Dewar
1999-08-18 0:00 ` Gisle S�lensminde
1999-08-18 0:00 ` Robert I. Eachus
1999-08-19 0:00 ` Gautier
1999-08-19 0:00 ` Robert I. Eachus
1999-08-20 0:00 ` Keith Thompson
1999-08-20 0:00 ` Robert Dewar
1999-08-18 0:00 ` Pascal MALAISE
1999-08-20 0:00 ` David Botton
1996-10-24 0:00 Garbage Collection H Brett Bolen
1989-01-10 19:16 Erland Sommarskog
1989-01-11 16:10 ` William Thomas Wolfe,2847,
1989-01-06 22:17 Erland Sommarskog
1989-01-08 18:40 ` William Thomas Wolfe,2847,
1989-01-09 3:56 ` Barry Margolin
1989-01-09 16:22 ` William Thomas Wolfe,2847,
1989-01-09 19:00 ` Barry Margolin
1989-01-10 2:50 ` William Thomas Wolfe,2847,
1989-01-11 9:22 ` Barry Margolin
1989-01-11 16:01 ` William Thomas Wolfe,2847,
1989-01-11 18:21 ` Barry Margolin
1989-01-12 2:43 ` William Thomas Wolfe,2847,
1989-01-15 7:14 ` Barry Margolin
1989-01-05 23:26 Erland Sommarskog
1988-12-31 0:04 Erland Sommarskog
1989-01-05 8:13 ` William Thomas Wolfe,2847,
1988-12-28 19:20 Erland Sommarskog
1988-12-30 0:52 ` Bill Wolfe
1988-12-26 23:37 Erland Sommarskog
1988-12-27 21:24 ` William Thomas Wolfe,2847,
1988-12-28 16:09 ` Snorri Agnarsson
1988-12-30 0:46 ` Bill Wolfe
1988-12-27 22:24 ` Bob Hathaway
1988-12-18 20:12 Erland Sommarskog
1988-12-20 19:04 ` Bill Wolfe
1988-12-13 20:07 Erland Sommarskog
1988-12-15 19:13 ` William Thomas Wolfe,2847,
[not found] <145@krafla.rhi.hi.is>
[not found] ` <272@fang.ATT.COM>
1988-03-29 13:47 ` From Modula to Oberon Denis Fortin
1988-03-30 15:32 ` Lawrence Crowl
1988-03-30 22:41 ` Hans Boehm
1988-03-31 6:27 ` Garbage Collection Richard Harter
1988-03-31 19:49 ` Hans Boehm
1988-04-01 5:43 ` Richard Harter
1988-04-01 18:43 ` Hans Boehm
1988-04-04 23:14 ` 00704a-Liber
1986-03-16 22:24 Garbage collection "Alexander L. Wolf"
[not found] <1979@mit-eddi.UUCP>
[not found] ` <2144@mit-eddie.UUCP>
1984-06-18 19:28 ` Abstraction In Ada Jon Mauney
1984-06-22 7:47 ` Doug Alan
1984-06-25 2:15 ` brad
1984-07-17 10:34 ` garbage collection Eric Smith
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