@thi.ng/pointfree/ops.js

Pointfree functional composition / Forth style stack execution engine

import { isArray } from "@thi.ng/checks/is-array";
import { illegalArgs } from "@thi.ng/errors/illegal-arguments";
import { $, $n } from "./safe.js";
const defOp1 = (op) => {
  return (ctx) => {
    const stack = ctx[0];
    const n = stack.length - 1;
    $n(n, 0);
    stack[n] = op(stack[n]);
    return ctx;
  };
};
const defOp2 = (op) => (ctx) => {
  const stack = ctx[0];
  const n = stack.length - 2;
  $n(n, 0);
  stack[n] = op(stack.pop(), stack[n]);
  return ctx;
};
const defOp2v = (f) => (ctx) => {
  $(ctx[0], 2);
  const stack = ctx[0];
  const b = stack.pop();
  const n = stack.length - 1;
  const a = stack[n];
  const isa = isArray(a);
  const isb = isArray(b);
  stack[n] = isa && isb ? __op2vAB(f, a, b) : isb && !isa ? __op2vB(f, a, b) : isa && !isb ? __op2vA(f, a, b) : illegalArgs("at least one arg must be an array");
  return ctx;
};
const __op2vAB = (f, a, b) => {
  const res = new Array(Math.min(a.length, b.length));
  for (let i = res.length - 1; i >= 0; i--) {
    res[i] = f(b[i], a[i]);
  }
  return res;
};
const __op2vA = (f, a, b) => {
  const res = new Array(a.length);
  for (let i = res.length - 1; i >= 0; i--) {
    res[i] = f(b, a[i]);
  }
  return res;
};
const __op2vB = (f, a, b) => {
  const res = new Array(b.length);
  for (let i = res.length - 1; i >= 0; i--) {
    res[i] = f(b[i], a);
  }
  return res;
};
export {
  defOp1,
  defOp2,
  defOp2v
};