Nullary types in Sanctuary

index.js

const $ = require('sanctuary-def')
const { create, env } = require('sanctuary')

const def = $.create({
  checkTypes: true,
  env: $.env
})

const MyBool = $.NullaryType
  ('dokidoki-types/MyBool')
  ('http://dokidokidriven.com/types/MyBool')
  ([])
  ((x) => x === 'T' || x === 'F')

const S = create({checkTypes: true, env: env.concat ([MyBool])})

const _myAnd =
  def ('myAnd')
  ({})
  ([MyBool, MyBool, MyBool])

const _myOr =
  def ('myOr')
  ({})
  ([MyBool, MyBool, MyBool])

const _myNot =
  def ('myNot')
  ({})
  ([MyBool, MyBool])

const myAnd = _myAnd
  ( a => b => {
    return a === 'T' && b === 'T' ? 'T' : 'F'
  })

const myOr = _myOr
  ( a => b => {
    return a === 'T' || b === 'T' ? 'T' : 'F'
  })

const myNot = _myNot
  ( a => {
    return a === 'T' ? 'F' : 'T'
  })

package.json

{
  "name": "nullary-types",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "sanctuary": "^2.0.0",
    "sanctuary-def": "^0.20.0"
  }
}