crocks/pointfree/bichain.js

A collection of well known Algebraic Datatypes for your utter enjoyment.

/** @license ISC License (c) copyright 2019 original and current authors */
/** @author Dale Francis (dalefrancis88) */

var curry = require('../core/curry')
var isFunction = require('../core/isFunction')

// bichain : bichain m => (e -> m c b) -> (a -> m c b) -> m e a -> m c b
function bichain(f, g, m) {
  if(!isFunction(f) || !isFunction(g)) {
    throw new TypeError('bichain: First two arguments must be Sum Type returning functions')
  }

  if(m && isFunction(m.bichain)) {
    return m.bichain.call(m, f, g)
  }

  throw new TypeError(
    'bichain: Third argument must be a Sum Type'
  )
}

module.exports = curry(bichain)