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Date: Sat, 09 Feb 2013 19:55:53 -0700
From: Michael Torrie <torriem@gmail.com>
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Subject: Re: Is Python programming language?
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Xref: csiph.com comp.lang.python:38546

On 02/09/2013 07:40 PM, Terry Reedy wrote:
> If the language has arrays, conditional execution, and explicit (while) 
> loops or recursion, you can be pretty sure it is Turing complete. I 
> presume this covers awk and bash. Something like the game of Life, where 
> the looping in implicit in the operation, is much harder to show Turing 
> complete. I suspect sed is non-trivial also.

All you have to do to show a language is turing complete is to implement
a turing machine in it.  Here's one in sed that I found:
http://www.catonmat.net/blog/proof-that-sed-is-turing-complete/