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Comment by mmjaa | Hacker News Reader

I got as far as trying to build and run it, but bugged out, thusly:

    $ ./one-page-j
    warning: this program uses gets(), which is unsafe.

    Segmentation fault: 11

Ah well, its still cute to try to read and understand ..

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The code was written on paper. Without the usual compile/debug cycles during development.

The amazing part is how little cleanup work is required to make the code work. It's an entire programming language after all!

It's not 64-bit clean. If you compile it as 32-bit it will run.

I got it to compile but what is it even supposed to do?

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.

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.

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