P.H.P. and Python (and Tcl/Tk!)

Lennart Sorensen lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org
Wed Apr 30 13:05:47 UTC 2008


On Wed, Apr 30, 2008 at 09:02:04AM -0400, Dave Mason wrote:
> As a computer languages researcher, I have to respond that the only real
> difference in the categories you cite: programming languages, scripting
> languages, and framework languages is marketing, pure and simple.
> 
> What Ousterhout and others are referring to as scripting languages are
> symply dynamically-typed languages, with convenient facilities to access
> other programs.
> 
> Those facilities to access other programs are available in standard C
> libraries... just a bit less conveniently (fork/pipe in the extreme).
> 
> Dynamically typed languages have been around since the 50s (LISP is
> contemporaneous with FORTRAN I), and include LISP, Scheme (a syntactic
> variant of LISP), Smalltalk, Ruby (a syntactic variant of Smalltalk) and
> APL.  There are compilers for these languages, but even interpreters
> (except for Ruby) have relatively little negative effect on performance
> (at most a few months worth of Moore's Law), partly because language
> primitives are often very powerful.
> 
> /bin/sh, awk, early Perl, PHP, and to some degree Tcl/Tk are slightly
> further down that road in that all data are strings, but some operations
> can interpret them as numbers, etc.  This has both performance and
> reliability/safety implications, but they are rarely critical.  Most of
> these languages are also pure interpreters and have some performance hit
> (a few more months worth of Moore's law).
> 
> The only significant theoretical distinction for a programming language
> is whether it is Turing complete: essentially does it have a while-loop
> equivalent, and some form of collections (strings will do).  All the
> languages listed above are Turing complete.  The closest thing that
> arguably is not is sed.

Someone here claims sed is turing complete (I dno't want to try and
prove it one way or the other that's for sure):
http://sed.sourceforge.net/grabbag/scripts/turing.sed

> Christopher Browne makes good points also about ego and programmers/
> operators (and in fact, there were many other levels in that heirarchy -
> blessedly mostly now gone).

I write both C and perl (lots of both) and some shell scripts.  I
consider all of it programming, although maybe for the shell scripts it
often doesn't seem much like programming.

-- 
Len Sorensen
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