It's a tiny interpreter. You can create vectors, add them, concatenate them, store them to variables, count their lengths, and so on. An example session:

    x=~5
    5
    0 1 2 3 4
    y=x,x
    10
    0 1 2 3 4 0 1 2 3 4
    x+y
    10
    0 2 4 6 8 0 1 2 3 4

To understand the source, the key are the arrays `C vt[]`, `A(vd[])()`, and `A(vm[])()`, which maps the verb token to the dyads and monads respectively. `V1` functions are monads, `V2` are dyads.

Should start a REPL. The `main` function looks like this:

  main(){
    C s[99];
    while(gets(s)) 
      pr(ex(wd(s)));
  }

which is a very direct expression of read-execute-print-loop.