curry.js

const isp = v => v === curry._;
const memo = fn => {
  const cache = {};
  return  (...p) => {
    const key = JSON.stringify(p);
    return key in cache ? cache[key] : cache[key] = fn(...p);
  }
};
function curry(fn, length = fn.length) {
  if (length === 0) return fn;
  const run = curry.wrap(length, (...args) => {
    const placeholders = args.reduce((acc, val, idx) => isp(val) ? [...acc, idx] : acc, []);
    const emptyArgsLength = length - (args.length - placeholders.length);
    
    if (emptyArgsLength > 0) {
      if (args.length - placeholders.length === 0) return run;
      else {
        return curry.wrap(emptyArgsLength, (...p) => curry(fn)(...p.reduce((acc, val) => {
          const phIdx = args.indexOf(curry._);
          if (phIdx === -1) return [...acc, val];
          else {
            acc.splice(phIdx, 1, val);
            return acc;
          }
        }, args)));
      }
    }
    else return fn(...args);
  });
  return run;
};
curry._ = Symbol('placeholder');
const makeFn = memo(n => eval(`fn => function _(${Array.from({length: n}, (_, i) => 'p' + i).join(',')}) {return fn(...arguments);};`));
curry.wrap = (n, fn) => makeFn(n)(fn);
const {_} = curry;
const a = (a,b,c) => a + b * c;
const f = curry(a);
const flip = curry(fn => curry((...[a, b, ...c]) => fn(b, a, ...c), fn.length));
const ff = flip(f);