@thi.ng/pointfree/loop.js

Pointfree functional composition / Forth style stack execution engine

import { $ } from "./safe.js";
import { $stackFn } from "./word.js";
const defLoop = (test, body) => {
  const _test = $stackFn(test);
  const _body = $stackFn(body);
  return (ctx) => {
    while (true) {
      ctx = _test(ctx);
      $(ctx[0], 1);
      if (!ctx[0].pop()) {
        return ctx;
      }
      ctx = _body(ctx);
    }
  };
};
const loopq = (ctx) => {
  const stack = ctx[0];
  $(stack, 2);
  const body = stack.pop();
  return defLoop(stack.pop(), body)(ctx);
};
const dotimes = (ctx) => {
  let stack = ctx[0];
  $(stack, 2);
  const w = $stackFn(stack.pop());
  for (let i = 0, n = stack.pop(); i < n; i++) {
    ctx[0].push(i);
    ctx = w(ctx);
  }
  return ctx;
};
export {
  defLoop,
  dotimes,
  loopq
};