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Recursion in Computer Science

Started byrusi <rustompmody@gmail.com>
First post2011-05-19 22:05 -0700
Last post2011-05-19 22:22 -0700
Articles 3 — 2 participants

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  Recursion in Computer Science rusi <rustompmody@gmail.com> - 2011-05-19 22:05 -0700
    Re: Recursion in Computer Science Chris Angelico <rosuav@gmail.com> - 2011-05-20 15:18 +1000
      Re: Recursion in Computer Science rusi <rustompmody@gmail.com> - 2011-05-19 22:22 -0700

#5812 — Recursion in Computer Science

Fromrusi <rustompmody@gmail.com>
Date2011-05-19 22:05 -0700
SubjectRecursion in Computer Science
Message-ID<725020f8-3a73-4a8a-a587-e4c4996bcb04@z15g2000prn.googlegroups.com>
There have been a number of unrelated discussions regarding recursion
on this list.
I believe that recursion occurs in a wider spread of areas than is
usually recognised.

Heres a list of some such areas.
Please note I am using recursion in a broad and somewhat fuzzy sense.
Narrow specific definitions would lead to conclusions like:
 -- Prolog has no functions or procedures so it has no recursion
 -- Since recursion is equivalent to stack + iteration therefore
Fortran supports recursion.

Heres (an initial approx to) such a list:
-------------------------------------------------------

recursive functions
recursive data -- eg linked lists, trees
nesting
self reference -- Y combinator
well founded induction
structural induction
bootstrapping
language to describe language -- syntax
  - yacc in yacc
language to describe language -- semantics
  - lisp in lisp -- metacircularity
Goedel's theorem <- meta-mathematics <- ordinary math
undecidability <- universal TM <- Turing machine as ordinary computer
reentrancy
 [An  OS-like program fails to be reentrant for the same reason that
 Fortan-like language fails to support recursion -- Non use of stack]
virtualization in OS
Introspection in modern languages
Models to metamodels
corecursion
  - laziness, infinite datastructures
  - semantics of generators/iterators in python
Von Neuman machine
  - code is data -- therefore quondam hardware becomes software
  - data can be code -- viruses

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#5814

FromChris Angelico <rosuav@gmail.com>
Date2011-05-20 15:18 +1000
Message-ID<mailman.1820.1305868733.9059.python-list@python.org>
In reply to#5812
On Fri, May 20, 2011 at 3:05 PM, rusi <rustompmody@gmail.com> wrote:
>  - data can be code -- viruses

It's not JUST viruses. There's plenty of legitimate reasons for your
data to actually be code... that's how compilers work! :)

Chris Angelico

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#5815

Fromrusi <rustompmody@gmail.com>
Date2011-05-19 22:22 -0700
Message-ID<dd4669f5-e2ff-4150-b63f-cd2f1207a00f@l14g2000pro.googlegroups.com>
In reply to#5814
On May 20, 10:18 am, Chris Angelico <ros...@gmail.com> wrote:
> On Fri, May 20, 2011 at 3:05 PM, rusi <rustompm...@gmail.com> wrote:
> >  - data can be code -- viruses
>
> It's not JUST viruses. There's plenty of legitimate reasons for your
> data to actually be code... that's how compilers work! :)
>
> Chris Angelico

Yes sure Thanks.
An exhaustive list would be much longer (and I got tired of typing)

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