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Re: Tail recursion to while iteration in 2 easy steps

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Date Sat, 05 Oct 2013 09:39:40 +0200
From Antoon Pardon <antoon.pardon@rece.vub.ac.be>
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Op 04-10-13 23:14, Terry Reedy schreef:
> On 10/4/2013 6:46 AM, Ian Kelly wrote:
>
>> On the other hand, if you start optimizing every tail call and not
>> just the recursive functions, then I can see where that could start to
>> get problematic for debugging -- as arbitrary functions get removed
>> from the stack traces just because they happened to end in tail calls.
>
> The idea of CPython space-optimizing tail calls when the call is made
> has been suggested on python-ideas. Guido verified that it is
> technically possible with the current bytecode interpreter but rejected
> it because it would arbitrarily mess up stack traces.

What does this mean?

Does it mean that a naive implementation would arbitrarily mess up
stack traces and he wasn't interested in investigating more
sophisticated implementations?

Does it mean he just didn't like the idea a stack trace wouldn't be a
100% represenatation of the active call history?

Does it mean he investigated more sphisticated implementations but found
them to have serious short comings that couldn't be remedied easily?

-- 
Antoon Pardon

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Thread

Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-01 17:30 -0400
  Re: Tail recursion to while iteration in 2 easy steps rusi <rustompmody@gmail.com> - 2013-10-01 22:16 -0700
    Re: Tail recursion to while iteration in 2 easy steps Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-10-02 10:23 +0200
      Re: Tail recursion to while iteration in 2 easy steps rusi <rustompmody@gmail.com> - 2013-10-02 06:29 -0700
    Re: Tail recursion to while iteration in 2 easy steps Ravi Sahni <ganeshsahni07@gmail.com> - 2013-10-03 22:57 +0530
      Re: Tail recursion to while iteration in 2 easy steps rusi <rustompmody@gmail.com> - 2013-10-04 03:52 -0700
  Re: Tail recursion to while iteration in 2 easy steps Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-10-02 10:17 +0200
    Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-02 11:59 -0700
    Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-02 14:05 -0700
      Re: Tail recursion to while iteration in 2 easy steps Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-10-04 11:49 +0200
        Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-04 10:51 +0000
        Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-04 18:32 -0400
          Re: Tail recursion to while iteration in 2 easy steps Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-10-07 19:15 +0200
            Re: Tail recursion to while iteration in 2 easy steps Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-10-07 19:57 +0200
              Re: Tail recursion to while iteration in 2 easy steps Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-10-08 10:56 +0200
                Re: Tail recursion to while iteration in 2 easy steps Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-10-08 12:49 +0300
            Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-07 16:42 -0400
            Re: Tail recursion to while iteration in 2 easy steps random832@fastmail.us - 2013-10-07 17:19 -0400
              Re: Tail recursion to while iteration in 2 easy steps Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-10-08 10:41 +0200
            Re: Tail recursion to while iteration in 2 easy steps MRAB <python@mrabarnett.plus.com> - 2013-10-07 22:39 +0100
            Re: Tail recursion to while iteration in 2 easy steps Piet van Oostrum <piet@vanoostrum.org> - 2013-10-07 18:03 -0400
            Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-07 15:47 -0700
              Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-07 23:50 +0000
                Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-07 17:24 -0700
                Formal-ity and the Church-Turing thesis rusi <rustompmody@gmail.com> - 2013-10-07 20:17 -0700
                Re: Formal-ity and the Church-Turing thesis Ravi Sahni <ganeshsahni07@gmail.com> - 2013-10-08 10:46 +0530
                Re: Formal-ity and the Church-Turing thesis rusi <rustompmody@gmail.com> - 2013-10-07 22:44 -0700
                Re: Formal-ity and the Church-Turing thesis Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-08 07:43 +0100
                Re: Formal-ity and the Church-Turing thesis Ravi Sahni <ganeshsahni07@gmail.com> - 2013-10-08 18:31 +0530
                Re: Formal-ity and the Church-Turing thesis rusi <rustompmody@gmail.com> - 2013-10-08 06:33 -0700
                Re: Formal-ity and the Church-Turing thesis Steven D'Aprano <steve@pearwood.info> - 2013-10-08 07:50 +0000
                Re: Formal-ity and the Church-Turing thesis Ravi Sahni <ganeshsahni07@gmail.com> - 2013-10-08 18:16 +0530
                Re: Formal-ity and the Church-Turing thesis Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-08 13:11 +0000
                Re: Formal-ity and the Church-Turing thesis Robert Day <robertkday@gmail.com> - 2013-10-08 14:25 +0100
                Re: Formal-ity and the Church-Turing thesis Chris Angelico <rosuav@gmail.com> - 2013-10-09 08:36 +1100
                Re: Formal-ity and the Church-Turing thesis Mark Janssen <dreamingforward@gmail.com> - 2013-10-07 22:19 -0700
                Re: Formal-ity and the Church-Turing thesis rusi <rustompmody@gmail.com> - 2013-10-07 23:01 -0700
                Re: Formal-ity and the Church-Turing thesis Mark Janssen <dreamingforward@gmail.com> - 2013-10-08 10:39 -0700
                Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-07 17:16 -0700
                Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-08 02:36 +0000
                Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-07 20:27 -0700
                Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve@pearwood.info> - 2013-10-08 09:22 +0000
                Re: Tail recursion to while iteration in 2 easy steps Charles Hixson <charleshixsn@earthlink.net> - 2013-10-09 15:45 -0700
                Re: Tail recursion to while iteration in 2 easy steps Piet van Oostrum <piet@vanoostrum.org> - 2013-10-07 22:46 -0400
                Re: Tail recursion to while iteration in 2 easy steps Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-10-08 10:25 +0300
                Re: Tail recursion to while iteration in 2 easy steps Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-10-08 11:18 +0200
              Re: Tail recursion to while iteration in 2 easy steps Piet van Oostrum <piet@vanoostrum.org> - 2013-10-07 22:45 -0400
                Re: Tail recursion to while iteration in 2 easy steps Mark Janssen <dreamingforward@gmail.com> - 2013-10-07 20:34 -0700
    Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-02 18:17 -0400
      Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-03 01:24 +0000
        Re: Tail recursion to while iteration in 2 easy steps Dave Angel <davea@davea.name> - 2013-10-03 01:39 +0000
        Re: Tail recursion to while iteration in 2 easy steps MRAB <python@mrabarnett.plus.com> - 2013-10-03 02:46 +0100
          Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-03 02:34 +0000
            Re: Tail recursion to while iteration in 2 easy steps Chris Angelico <rosuav@gmail.com> - 2013-10-03 14:14 +1000
            Re: Tail recursion to while iteration in 2 easy steps random832@fastmail.us - 2013-10-03 10:16 -0400
            Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-03 15:04 -0400
        Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-02 22:41 -0400
          Re: Tail recursion to while iteration in 2 easy steps Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-04 01:30 +0000
        Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-02 23:06 -0400
        Re: Tail recursion to while iteration in 2 easy steps random832@fastmail.us - 2013-10-03 10:14 -0400
        Literal syntax for frozenset, frozendict (was: Tail recursion to while iteration in 2 easy steps) Ben Finney <ben+python@benfinney.id.au> - 2013-10-04 10:18 +1000
        Re: Literal syntax for frozenset, frozendict Ethan Furman <ethan@stoneleaf.us> - 2013-10-03 18:31 -0700
    Re: Tail recursion to while iteration in 2 easy steps Duncan Booth <duncan.booth@invalid.invalid> - 2013-10-03 14:52 +0000
      Re: Tail recursion to while iteration in 2 easy steps Neil Cerutti <neilc@norwich.edu> - 2013-10-03 16:03 +0000
        Re: Tail recursion to while iteration in 2 easy steps Duncan Booth <duncan.booth@invalid.invalid> - 2013-10-04 10:16 +0000
          Re: Tail recursion to while iteration in 2 easy steps Ian Kelly <ian.g.kelly@gmail.com> - 2013-10-04 04:41 -0600
          Re: Tail recursion to while iteration in 2 easy steps Ian Kelly <ian.g.kelly@gmail.com> - 2013-10-04 04:46 -0600
            Re: Tail recursion to while iteration in 2 easy steps Duncan Booth <duncan.booth@invalid.invalid> - 2013-10-04 11:16 +0000
          Re: Tail recursion to while iteration in 2 easy steps Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-10-04 14:11 +0300
          Re: Tail recursion to while iteration in 2 easy steps Terry Reedy <tjreedy@udel.edu> - 2013-10-04 17:14 -0400
          Re: Tail recursion to while iteration in 2 easy steps Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-10-05 09:39 +0200
          Re: Tail recursion to while iteration in 2 easy steps random832@fastmail.us - 2013-10-07 17:27 -0400
            Re: Tail recursion to while iteration in 2 easy steps Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-10-08 10:11 +0300
          Re: Tail recursion to while iteration in 2 easy steps Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-10-08 11:43 +0200

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