Subject: Re: Xah on Lisp
From: rpw3@rpw3.org (Rob Warnock)
Date: Wed, 20 Aug 2008 20:22:31 -0500
Newsgroups: comp.lang.lisp
Message-ID: <M_KdnYvqUvfKXjHVnZ2dnUVZ_iydnZ2d@speakeasy.net>
xahlee@gmail.com <xahlee@gmail.com> wrote:
+---------------
| Don Geddis <d...@geddis.org> wrote:
| > You have not defined what it means for a syntax to have "power", nor have
| > you given any specific examples of how the five characters "reduce" that
| > so-called power.
| 
| You want me to define the power of a computer language?
| 
| You think i don't give sufficient explanation and needs to define the
| term?
| 
| are you aware that defining such a thing is nearly impossible?
+---------------

You, on the other hand, are apparently not aware that this has been
an active area of computer science research for decades!! E.g., see:

    http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.51.4656
    "On the expressive power of programming languages"
    Matthias Felleisen
    [In "Science of Computer Programming", Springer-Verlag (1991).]

    Abstract:
    The literature on programming languages contains an abundance of
    informal claims on the relative expressive power of programming
    languages, but there is no framework for formalizing such statements
    nor for deriving interesting consequences. As a first step in
    this direction, we develop a formal notion of expressiveness and
    investigate its properties. To validate the theory, we analyze
    some widely held beliefs about the expressive power of several
    extensions of functional languages. Based on these results, we
    believe that our system correctly captures many of the informal
    ideas on expressiveness, and that it constitutes a foundation
    for further research in this direction.
    ...

Full paper available here:

    ftp://ftp.cs.indiana.edu/pub/scheme-repository/doc/pubs/express.ps.gz
    http://www.cs.rice.edu/CS/PLT/Publications/scp91-felleisen.ps.gz

+---------------
| Some computer scientist, tried to formalize it in some mathematical
| way, but basically went no where (such's failure, for example, can
| be attributed or judged by lack of effectiveness, practicality, utility).
| 
| Do you need me to cite papers, books, on these definition issues i
| discussed above?
+---------------

Yes.


-Rob

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Rob Warnock			<rpw3@rpw3.org>
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