What can you do in LISP that you can't do in Python

[ssthapa at classes.cs.uchicago.edu]

Alex Martelli <aleaxit at yahoo.com> wrote:
>
>Python, Scheme, Common Lisp, and a zillion other languages (including
>C, C++, Java, Fortran, Cobol, PL/I, Ada, Perl, Basic, ...) are all
>"Turing Complete" (to within the physical limitations imposed by
>finiteness of computer hardware), so you will never find anything
>that you "could do in X and couldn't do in Y" for any X and Y in
>this set of languages.  

    Actually, I don't think this is quite true.  I believe this 
holds only if the Church-Turing Thesis is true.  The original Church-Turing 
thesis basically states that every effective calculation can be 
done by a Turing machine. I don't think the Church-Turing Thesis has 
been proved let alone the much stronger version that a Turing machine
can compute whatever any machine working with a finite set of instructions
and data can compute.  
    If the stronger version of the C-T thesis is incorrect then it is possible
for programs in one language to compute things that a program in another
language can't compute.  However, both languages would share a common subset
of functions that can be computed.


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Suchandra Thapa                       | "There are only two kinds of math . 
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