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Little Comparison Between Common Lisp and C and Shell Script
============================================================

Here is a little program: compute factorial of 42,
implemented in C and in Common Lisp and in Shell Script.

We note that:

1- the C program runs faster.

2- the C program gives wrong results (who expected differently?).

3- the C program, while being strictly equivalent, counts more
   parentheses, if you count also the braces, the brackets, the
   angle-brackets (of #include), and the semi-colon that surround
   statements…
   
4- Shell Script is measurably slowest.

5- Shell script has the lowest 'syntax' count (parenthesis and other
   syntactical structures).
   

Said otherwise:

1- You cannot feel the difference of run-time between the Lisp program and the C program.

2- the Lisp program gives the correct result.

3- the lisp program is more concise and counts fewer parentheses.

4- the shell script program is most concise and counts even fewer parens.


==== fact.c =======

42! = 0
        0.00 real         0.00 user         0.00 sys

==== fact.lisp ====

42! = 1405006117752879898543142606244511569936384000000000
        0.00 real         0.00 user         0.00 sys

==== fact.unix ====

42! = 1405006117752879898543142606244511569936384000000000
       real    0m      0.172s user     0m0.064s        sys     0m0.120s
       
===================

fact.lisp             24 parentheses, braces, brackets, angle-brackets, semi-colons, commas
fact.c                34 parentheses, braces, brackets, angle-brackets, semi-colons, commas
fact.unix             8 parentheses, braces, brackets, angle-brackets, semi-colons, commas

==== fact.lisp ====

(defun fact (x)
  (if (zerop x)
      1
      (* x (fact (1- x)))))

(defun main ()
  (format t "~%~D! = ~D~%" 42 (fact 42))
  (quit 0))

==== fact.c ====

#include <stdio.h>

int fact(int x)
{
    if(0==x)
    {
        return(1);
    }
    else
    {
        return(x*fact(x-1));
    }
}

int main()
{
   printf("\n%d! = %d\n",42,fact(42));
   return(0);
}

===================

==== fact.unix ====
#!/bin/sh                                                                       

n=42
nf=1
for n in $(seq 1 $n); do
    nf=$(echo "$nf $n * p" | dc)
done
echo $nf


Note: to compare a more complex and real program implemented in Lisp and in C, 
have a look at https://github.com/informatimago/scquery (sources/ and sources-cl/).

scquery in Lisp     1279 parentheses, braces, brackets, angle-brackets, semi-colons, commas
scquery in C        8052 parentheses, braces, brackets, angle-brackets, semi-colons, commas

TODO: write scquery in POSIX UNIX.