@thi.ng/pointfree/word.js

Pointfree functional composition / Forth style stack execution engine

import { isArray } from "@thi.ng/checks/is-array";
import { isFunction } from "@thi.ng/checks/is-function";
import { compL } from "@thi.ng/compose/comp";
import { $ } from "./safe.js";
import { tos } from "./stack.js";
const $stackFn = (f) => isArray(f) ? defWord(f) : f;
const __compile = (prog) => prog.length > 0 ? compL.apply(
  null,
  prog.map(
    (w) => !isFunction(w) ? (ctx) => (ctx[0].push(w), ctx) : w
  )
) : (ctx) => ctx;
const unwrap = ([stack], n = 1) => n === 1 ? tos(stack) : stack.slice(Math.max(0, stack.length - n));
const defWord = (prog, env, mergeEnv = true) => {
  const w = __compile(prog);
  return env ? mergeEnv ? (ctx) => (w([ctx[0], ctx[1], { ...ctx[2], ...env }]), ctx) : (ctx) => (w([ctx[0], ctx[1], { ...env }]), ctx) : w;
};
const defWordU = (prog, n = 1, env, mergeEnv = true) => {
  const w = __compile(prog);
  return env ? mergeEnv ? (ctx) => unwrap(w([ctx[0], ctx[1], { ...ctx[2], ...env }]), n) : (ctx) => unwrap(w([ctx[0], ctx[1], { ...env }]), n) : (ctx) => unwrap(w(ctx), n);
};
const exec = (ctx) => ($(ctx[0], 1), $stackFn(ctx[0].pop())(ctx));
const $try = (ctx) => {
  const stack = ctx[0];
  $(stack, 2);
  const err = stack.pop();
  try {
    return exec(ctx);
  } catch (e) {
    stack.push(e, err);
    return exec(ctx);
  }
};
const execjs = (ctx) => {
  const stack = ctx[0];
  $(stack, 1);
  const [fn, ...args] = stack.pop();
  stack.push(fn(...args));
  return ctx;
};
export {
  $stackFn,
  $try,
  defWord,
  defWordU,
  exec,
  execjs,
  unwrap
};