variations on a theme

This is the grokout experiment, which is one of several variations on a theme:

build and run the grokout ruleset

Here is the grokout.lmn ruleset as a web page: grokout

Compile the grokout ruleset as a shebang script called grokout.lm:

 [user@machine web]$ make grokout.lm
 lmn2m -o grokout.lm -s /usr/bin/lm grokout.lmn
 chmod +x grokout.lm

Here is some text that contains a good deal of material that is recognised and some that is not - it's the code for Eratosthenes' sieve in Javascript:

 [user@machine web]$ cat /home/user/src/dmdscript/1.0.6/dmdscript/sieve.ds

 /* Eratosthenes Sieve prime number calculation. */

 size = 8190;
 sizepl = 8191;

 var flags = new Array(sizepl);

 var i, prime, k, count, iter;

 print("10 iterations\n");
 starttime = new Date();
 for (iter = 1; iter <= 10; iter++)
 {   count = 0;
     for (i = 0; i <= size; i++)
         flags[i] = true;
     for (i = 0; i <= size; i++)
     {   if (flags[i])
         {   prime = i + i + 3;
             k = i + prime;
             while (k <= size)
             {
                 flags[k] = false;
                 k += prime;
             }
             count += 1;
         }
     }
 }
 elapsedtime = new Date() - starttime;
 print("\n" + count + " primes\n");
 print("elapsed time = " + elapsedtime + "\n");

Here is the result of applying the filtering translator ruleset - anything that it recognises as matching expr ";" is translated, everything else is copied (it is not suggested that the resulting output is of any use to anyone, and it is certainly no longer valid as Javascript):

 [user@machine web]$ ./grokout.lm /home/user/src/dmdscript/1.0.6/dmdscript/sieve.ds

 /* Eratosthenes Sieve prime number calculation. */

 (CODE (set size 8190))
 (CODE (set sizepl 8191))

 var flags = new Array(CODE sizepl)

 var i, prime, k, count, (CODE iter)

 print("10 iterations\n");
 starttime = new Date();
 for ((CODE (set iter 1)) iter <= (CODE 10) iter++)
 {   (CODE (set count 0))
     for ((CODE (set i 0)) i <= (CODE size) i++)
         (CODE (set flags[i] true))
     for ((CODE (set i 0)) i <= (CODE size) i++)
     {   if (flags[i])
         {   (CODE (set prime (add (add i i) 3)))
             (CODE (set k (add i prime)))
             while (k <= size)
             {
                 (CODE (set flags[k] false))
                 k += (CODE prime)
             }
             count += (CODE 1)
         }
     }
 }
 elapsedtime = new Date() (CODE (neg starttime))
 print("\n" + count + " primes\n");
 print("elapsed time = " + elapsedtime + "\n");