Re: Adding thousands separators

From	Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups	comp.lang.forth
Subject	Re: Adding thousands separators
Date	2012-03-03 23:49 +0100
Organization	1&1 Internet AG
Message-ID	<jiu760$cp6$1@online.de> (permalink)
References	(1 earlier) <c00cddcd-5a7e-46c3-b107-d5fa7cf8d7af@j8g2000yqm.googlegroups.com> <be715108-58e0-4ea8-a7e7-71ebfc9bfb55@l1g2000vbc.googlegroups.com> <m0b2km.hm2@spenarnc.xs4all.nl> <7xaa3y2at9.fsf@ruckus.brouhaha.com> <LuGdnfHKuO0W08_SnZ2dnUVZ_oOdnZ2d@supernews.com>

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Andrew Haley wrote:
> When I did Forth full-time (mostly in industrial control
> applications) I was terrified of GC and knew that it wasn't
> appropriate.

As long as you can make the GC a low-priority incremental background 
task, this isn't a problem, rather the contrary.  GC allows you to 
implement memory management with a short (and constant) allocation time, 
something that helps a lot, when your application does dynamic memory 
allocation in the hard realtime path.

Anton's GC is a conservative garbage collector, something that can be 
added as an afterthought.  But IMHO, the best designs are the ones where 
you had made the thought before.  So in a "managed Forth" (where you 
don't have to care about your memory, it is managed for you), there 
would be two sorts of managed objects: on one side, strings and buffers, 
which may resize dynamically, and then may move (the GC there is also a 
compactor), on the other side, OOP objects, which have a static size, 
but do not need to move (there is no sufficient advantage in compacting 
them).

Awareness means that your OOP system knows that OOP objects are garbage 
collected, and whenever you do an assignment of a white object (maybe 
dead) to an object pointer, it "grays" out the assigned object (gray is 
the "alive, but not scanned" color for incremental GCs).  The OOP system 
also can know which variables in an object are actual pointers, reducing 
the false positives (there may still be false positives through other 
possible roots, like stacks), lowering the overall effort.  You can even 
avoid scanning the entire dictionary by requiring that object pointers 
are declared as such (which they usually are) - they then either go to a 
dedicated memory region for quick and easy scanning of roots, or they 
are chain-linked together.

And there are further opportunities.  Objects may have a dedicated life-
time, e.g. a network connection may have an idle timeout.  Instead of 
adding another timeout event queue, you could let the garbage collector 
know that there's a timeout field in the object, and when the timestamp 
there is less than the current time, it has timed out, and doesn't need 
scanning.

There's actually a third class of managed memory, that's the one of 
large data chunks (images, pixel buffers, and alike).  Here, the most 
important thing is that reclaiming this memory also gives it back to the 
OS, which usually requires allocating using mmap and reclaiming using 
munmap (you should also reclaim the unused part of the string memory 
after compaction).  Otherwise you have the JVM situation, where you have 
the combined disadvantage of a non-incremental GC (stopping you here and 
there), and the memory usage of applications grows and grows, and never 
shrinks.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

Thread

Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-13 21:24 +1100
  Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-02-13 13:05 -0800
    Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-16 10:19 +1100
  Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-02-15 08:48 +0100
    Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-02-23 22:46 -0800
      Re: Adding thousands separators "A. K." <akk@nospam.org> - 2012-02-24 08:07 +0100
      Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-02-24 15:00 +0100
        Re: Adding thousands separators "Elizabeth D. Rather" <erather@forth.com> - 2012-02-24 08:29 -1000
          Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-02-25 00:11 +0100
        Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-02-27 23:28 -0800
          Re: Adding thousands separators Alex McDonald <blog@rivadpm.com> - 2012-02-28 01:37 -0800
            Re: Adding thousands separators Ron Aaron <rambamist@gmail.com> - 2012-02-28 15:06 +0200
          Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-02-29 09:29 +0100
            Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-29 03:00 -0600
              Re: Adding thousands separators The Beez <the.beez.speaks@gmail.com> - 2012-02-29 03:44 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-29 11:19 -0600
            Re: Adding thousands separators hughaguilar96@yahoo.com - 2012-02-29 22:48 -0800
              Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-03-01 08:38 +0100
                Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-01 00:57 -0800
                Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-03-01 18:23 +0100
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-01 17:22 -0800
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-01 18:00 -0800
                Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-01 22:14 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-02 06:58 -0800
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-02 11:07 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-03-02 13:13 -0600
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-02 11:25 -0800
                Re: Adding thousands separators Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-03 11:00 +0000
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-03 03:17 -0800
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-03 12:30 +0000
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-03 11:39 -0800
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-06 16:31 -0800
                Re: Adding thousands separators mhx@iae.nl (Marcel Hendrix) - 2012-03-03 15:52 +0200
                Re: Adding thousands separators Coos Haak <chforth@hccnet.nl> - 2012-03-03 16:23 +0100
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-03 10:19 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-03 12:35 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-03-03 11:02 -0600
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-03 17:25 +0000
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-03 10:14 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-03-03 14:14 -0600
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-03 14:52 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-03-04 03:39 -0600
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-04 15:02 +0000
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-03-03 14:11 -0600
                Re: Adding thousands separators Bernd Paysan <bernd.paysan@gmx.de> - 2012-03-03 23:49 +0100
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-03 15:50 -0800
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-04 15:38 +0000
                Re: Adding thousands separators Bernd Paysan <bernd.paysan@gmx.de> - 2012-03-04 18:08 +0100
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-03-04 11:20 -0600
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-04 17:45 +0000
                Re: Adding thousands separators Bernd Paysan <bernd.paysan@gmx.de> - 2012-03-04 23:50 +0100
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-05 14:39 +0000
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-03-06 13:01 -0800
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-03-12 16:05 +0000
                Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-03 15:45 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-03 17:56 -0800
                Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-05 15:41 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-06 11:27 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-03 11:01 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-02 05:53 -0800
                Re: Adding thousands separators Bernd Paysan <bernd.paysan@gmx.de> - 2012-03-03 01:49 +0100
      Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-29 17:20 +1100
        Re: Adding thousands separators "A. K." <akk@nospam.org> - 2012-02-29 07:51 +0100
        Re: Adding thousands separators hughaguilar96@yahoo.com - 2012-02-29 21:26 -0800
          Re: Adding thousands separators "WJ" <w_a_x_man@yahoo.com> - 2012-03-03 03:45 +0000
          Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-04 20:49 +1100
            Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-03-04 15:16 +0100
              Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-06 15:06 +1100
                Re: Adding thousands separators Hans Bezemer <the.beez.speaks@gmail.com> - 2012-03-06 08:32 +0100
            Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-05 15:06 -0800
              Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-06 15:03 +1100
              Re: Adding thousands separators hwfwguy@gmail.com - 2012-03-06 20:29 -0800
                Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-06 23:18 -0800
                Re: Adding thousands separators John Passaniti <john.passaniti@gmail.com> - 2012-03-07 06:07 -0800
                Re: Adding thousands separators hwfwguy@gmail.com - 2012-03-07 06:36 -0800
                Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-03-07 16:19 -0800
                Re: Adding thousands separators Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-08 10:51 +0000
  Re: Adding thousands separators Doug Hoffman <glidedog@gmail.com> - 2012-02-15 20:18 -0500
    Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-17 12:29 +1100
      Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-17 09:42 -0800
        Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-20 15:24 +0000
          Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-20 20:41 -0800
            Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-21 16:46 +0000
              Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-21 12:23 -0600
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-21 11:32 -0800
                Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-22 12:46 +1100
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-22 10:08 +0000
                Re: Adding thousands separators "Elizabeth D. Rather" <erather@forth.com> - 2012-02-22 08:51 -1000
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-22 14:28 -0800
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-23 13:13 +0000
                Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-24 14:32 +1100
                Re: Adding thousands separators "Elizabeth D. Rather" <erather@forth.com> - 2012-02-23 19:53 -1000
                Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-03 12:47 +1100
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-03-02 22:26 -0800
                Re: Adding thousands separators Jan Coombs <jan_2011-02@murray-microft.co.uk> - 2012-03-03 14:32 +0000
                Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-04 21:31 +1100
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-03-04 10:07 -0800
                Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-06 15:31 +1100
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-03-05 22:26 -0800
                Re: Adding thousands separators Josh Grams <josh@qualdan.com> - 2012-03-06 12:32 +0000
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-24 05:04 -0800
                Re: Adding thousands separators "Elizabeth D. Rather" <erather@forth.com> - 2012-02-24 08:30 -1000
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-22 04:28 -0600
                Re: Adding thousands separators stephenXXX@mpeforth.com (Stephen Pelc) - 2012-02-22 14:59 +0000
                Re: Adding thousands separators stephenXXX@mpeforth.com (Stephen Pelc) - 2012-02-22 18:05 +0000
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-22 07:49 -0800
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-02-22 12:46 -0800
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-22 18:24 -0800
                Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-24 13:23 +1100
              Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-21 11:29 -0800
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-22 09:56 +0000
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-22 07:37 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-22 10:30 -0600
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-22 16:24 +0000
                Re: Adding thousands separators Brad <hwfwguy@gmail.com> - 2012-02-23 07:44 -0800
                Re: Adding thousands separators Bernd Paysan <bernd.paysan@gmx.de> - 2012-02-23 17:54 +0100
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-23 16:51 +0000
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-23 11:49 -0600
                Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-02-23 13:26 -0800
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-23 15:58 -0600
                Re: Adding thousands separators Bernd Paysan <bernd.paysan@gmx.de> - 2012-02-26 02:25 +0100
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-26 03:24 -0600
                Re: Adding thousands separators anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-02-26 13:40 +0000
                Re: Adding thousands separators Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-02-26 11:06 -0600
                Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-23 15:02 -0800
  Re: Adding thousands separators Doug Hoffman <glidedog@gmail.com> - 2012-02-16 13:21 -0500
  Re: Adding thousands separators Paul Rubin <no.email@nospam.invalid> - 2012-02-16 20:44 -0800
    Re: Adding thousands separators Coos Haak <chforth@hccnet.nl> - 2012-02-17 21:32 +0100
  Re: Adding thousands separators "A. K." <akk@nospam.org> - 2012-02-17 22:41 +0100
    Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-17 18:52 -0800
      Re: Adding thousands separators "A. K." <akk@nospam.org> - 2012-02-18 10:39 +0100
        Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-02-18 21:22 +1100
          Re: Adding thousands separators "A. K." <akk@nospam.org> - 2012-02-18 13:12 +0100
            Re: Adding thousands separators "Peter Knaggs" <pjk@bcs.org.uk> - 2012-02-18 16:30 +0000
              Re: Adding thousands separators Jan Coombs <jan_2011-02@murray-microft.co.uk> - 2012-02-18 17:08 +0000
              Re: Adding thousands separators BruceMcF <agila61@netscape.net> - 2012-02-18 14:46 -0800
            Re: Adding thousands separators "Ed" <nospam@invalid.com> - 2012-03-04 20:47 +1100
  Re: Adding thousands separators Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-02-28 17:03 -0800
  Re: Adding thousands separators "WJ" <w_a_x_man@yahoo.com> - 2012-03-01 18:13 +0000
    Re: Adding thousands separators Alex McDonald <blog@rivadpm.com> - 2012-03-01 12:46 -0800
  Re: Adding thousands separators "WJ" <w_a_x_man@yahoo.com> - 2012-03-01 18:52 +0000

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