Re: FWIW: script vs. configurtion file

[saint@eng.it]

Joel Rees writes:
 > On Wed, Jul 23, 2014 at 9:29 PM,  <saint@eng.it> wrote:
 > > Zenaan Harkness writes:
 > >
 > >> So thank you Joel for spending the time to describe these
 > >  > concepts as 'pedantically' as you have. Your descriptions
 > >  > are an excellent grounding for the conversation which is
 > >  > undoubtedly going to continue :)
 > >
 > > One question. Can you give me an example of Turing completeness with
 > > just declarations?
 > >
 > > If not, the description you refer to may be valid only when discussing
 > > "configuration", and even there there is some loss.
 > >
 > > [Scripts, in the Unix world - and GNU is a Unix replacement - are
 > >  something almost Turing complete or Turing complete, depending on the
 > >  language used for the a given script]
 > 
 > You know, I don't think I've seen very many configuration scripts,
 > even those using the richer aspects of bash, perl, python, et. al.,
 > which have made use of Turing completeness.
 > 
 > (And I do not think you intend to mean that the configuration scripts
 > themselves might sometimes be Turing complete.)

1) Yes  you are right!  The correct version  of my sentence  in square
   brackets should have been

   [Scripts, in the Unix world - and GNU is a Unix replacement - are
    something written in an almost-Turing-complete or Turing-complete
    language]

   Blame on me for the error, kudos to you for understanding what I
   really meant.

2) When a program has a declarative configuration file, then you can
   select among a certain number of fixed behaviours. When a program
   has a Turing complete language for its configuration then that
   program is likely to be quickly extensible. 

   I admit that you could write a declarative configuration that lets
   you specify "scripts" to be executed by the "configured" program
   or the system. Frankly, I would put everything into a "script", much
   easier to write and maintain.
   
If the argument of the discussion was whether a declarative language
has or has not a grammar, then my point is outside this discussion,
and chances are that my limited English skills prevented me from
understanding that.

But I still have the feeling that the original post tried to
demonstrate a more general equivalence between declarative
configuration and "scripted" configuration.

That's all, folks :)!

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Warning: gnome-config-daemon considered more dangerous than GOTO