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Re: Fibonacci series recursion error

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On Sun, 01 May 2011 18:24:30 -0400, Terry Reedy
  <tjreedy@udel.edu> wrote:
:  This does not make linear recursion 'bad', just impractical for general 
:  use on finite-memory machines. While I consider it very useful for 
:  learning, it is unnecessary because it is easy to write an iterative 
:  version. So called tail-recursion optimization saves memory by REMOVING 
:  RECURSION and replacing it with iteration.
: (...)
:  Python does not do this automatically because 1) it can be a semantic 
:  change under some circumstances; 2) one who wants the iterative version 
:  can just as easily write it directly;

That's the silliest argument I ever heard.  The programmer should write
the code the way he and application domain experts think, i.e. very
often recursively.  The compiler should generate code the way the CPU
thinks (most optimally), i.e. iteratively.

Of course, I am not saying that one should always model problems
recursively, and thus also not that one should implement them
recursively.  Just that when a model is agreed recursively between
the stakeholders, one should get a compiler to do the optimisation,
not a programmer.

I always thought of python as a step forward, in the way it allows 
direct expression of so many alternative modes of thinking (imperative,
functional, recursion, iterators, etc).  If what you say is python
philosophy, it is a step backward in requiring the programmer to
think more about low-level technical matters which even C has managed
to leave for the compiler.

:        and 3) Python has a better way to 
:  process collections that removes essentially all the boilerplate in the 
:  recursive-call and while-loop versions:


-- 
:-- Hans Georg

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Re: Fibonacci series recursion error Paul Rudin <paul.nospam@rudin.co.uk> - 2011-04-30 15:40 +0100
  Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-01 09:18 +0100
    Re: Fibonacci series recursion error Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-01 09:04 +0000
      Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-01 10:27 +0100
        Re: Fibonacci series recursion error Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-01 11:56 +0000
          Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-01 14:15 +0100
            Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-02 06:49 +1000
              Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-02 06:36 +0100
                Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-02 16:28 +1000
                Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-02 16:30 +1000
                Re: Fibonacci series recursion error (slightly OT) Dave Angel <davea@ieee.org> - 2011-05-02 08:50 -0400
            Re: Fibonacci series recursion error Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-02 01:09 +0000
              Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-02 10:41 +0100
        Re: Fibonacci series recursion error Terry Reedy <tjreedy@udel.edu> - 2011-05-01 18:24 -0400
          Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-02 14:14 +0100
            Re: Fibonacci series recursion error Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-02 16:41 +0000
              Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-02 21:02 +0100
                Re: Fibonacci series recursion error Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-03 00:21 +0000
                Re: Fibonacci series recursion error rusi <rustompmody@gmail.com> - 2011-05-02 20:42 -0700
                Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-03 06:13 +0100
                Re: Fibonacci series recursion error Robert Brown <robert.brown@gmail.com> - 2011-05-08 01:44 -0400
                Re: Fibonacci series recursion error Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-08 12:59 +0000
                Development time vs. runtime performance (was: Fibonacci series recursion error) Teemu Likonen <tlikonen@iki.fi> - 2011-05-08 19:34 +0300
                Re: Development time vs. runtime performance (was: Fibonacci series recursion error) Chris Angelico <rosuav@gmail.com> - 2011-05-09 12:49 +1000
                Re: Development time vs. runtime performance (was: Fibonacci series recursion error) Robert Brown <robert.brown@gmail.com> - 2011-05-08 23:01 -0400
            Re: Fibonacci series recursion error Terry Reedy <tjreedy@udel.edu> - 2011-05-02 14:56 -0400
            Re: Fibonacci series recursion error Chris Angelico <rosuav@gmail.com> - 2011-05-03 07:56 +1000
              Re: Fibonacci series recursion error Hans Georg Schaathun <hg@schaathun.net> - 2011-05-03 08:01 +0100

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