From: "Clément Pit--Claudel" <clement.pit@gmail.com>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: John Mastro <john.b.mastro@gmail.com>, emacs-devel <emacs-devel@gnu.org>
Subject: Re: [PATCH] Elpa: Pinpoint semantics of `seq-subseq' for streams
Date: Thu, 15 Sep 2016 18:18:19 -0400 [thread overview]
Message-ID: <b6a95523-21b1-0ed7-3993-fa05557e319a@gmail.com> (raw)
In-Reply-To: <87sht0an3u.fsf@web.de>
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On 2016-09-15 17:07, Michael Heerdegen wrote:
> Clément Pit--Claudel <clement.pit@gmail.com> writes:
>
>>> but the same applies to a list.
>>
>> Not exactly: the list needs to be fully built before you iterate
>> over it. That's when the memory problems occur. So yes, during
>> iteration you can discard the cons cells that you've already seen
>> in both cases, but in the list case these cells need to all be
>> constructed and kept in memory beforehand.
>
> But I think what John said is still a valid argument: If you
> construct a stream of lines of a process's output (just for example),
> of, say, 10000 lines, you create 10000 new objects (strings), and you
> discard 10000 - n of them. They all need to be garbage collected.
This is orthogonal to the list-vs-stream debate, isn't it?
> This will not only take a large amount of time - garbage collection
> happens not all the time, so memory will be filled to a certain
> amount as well. But I think the impact of garbage collection of that
> many objects is a more serious problem than memory usage anyway.
[citation needed] :) Garbage collection costs time; memory costs, well, memory. It's just a trade-off.
> Instead, a simple loop incrementing a position variable or something
> like that might be more appropriate (efficient).
Sure, but again: how is this related to lists vs strings? Lists need to be garbage collected just the same.
> Instead, a simple loop incrementing a position variable or something
> like that might be more appropriate (efficient).
I'm not sure what you mean :\ Are you saying that sometime streams are not the right solution for a given problem? I agree fully :)
Cheers,
Clément.
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next prev parent reply other threads:[~2016-09-15 22:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 16:23 [PATCH] Elpa: Pinpoint semantics of `seq-subseq' for streams Michael Heerdegen
2016-09-13 18:02 ` Clément Pit--Claudel
2016-09-13 21:17 ` Michael Heerdegen
2016-09-14 1:24 ` Clément Pit--Claudel
2016-09-14 15:05 ` Michael Heerdegen
2016-09-14 23:26 ` Clément Pit--Claudel
2016-09-15 0:51 ` John Mastro
2016-09-15 2:00 ` Clément Pit--Claudel
2016-09-15 17:01 ` John Mastro
2016-09-15 21:07 ` Michael Heerdegen
2016-09-15 22:18 ` Clément Pit--Claudel [this message]
2016-09-15 22:28 ` Michael Heerdegen
2016-09-15 22:52 ` Clément Pit--Claudel
2016-09-15 0:58 ` Michael Heerdegen
2016-09-15 3:47 ` Clément Pit--Claudel
2016-09-15 8:42 ` Nicolas Petton
2016-09-15 22:30 ` Michael Heerdegen
2016-09-15 23:08 ` Nicolas Petton
2016-09-15 21:29 ` Michael Heerdegen
2016-09-14 1:28 ` John Wiegley
2016-09-14 15:15 ` Michael Heerdegen
2016-09-13 22:20 ` Nicolas Petton
2016-09-13 22:40 ` Michael Heerdegen
2016-09-14 8:25 ` Nicolas Petton
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