purescript-easy-ffi

Most foreign imports in PureScript follow a familiar pattern:

-- In Module.purs
foreign import foo :: Number -> Number -> Number -> Number

// In Module.js
exports.foo = function(x) {
  return function (y) {
    return function (z) {
      return (x + y) * z; // <- the actually interesting part!
    };
  };
};

Yuck! Using Easy FFI you can scrap all that boilerplate and write the above as:

foo :: Number -> Number -> Number -> Number
foo = unsafeForeignFunction ["x", "y", "z"] "(x + y) * z"

Easy! We can also define foreign functions returning monadic actions, by including an empty argument, e.g.

log :: forall r. String -> Eff (console :: Unit | r) Unit
log = unsafeForeignProcedure ["string", ""] "console.log(string);" -- note the extra ""

which is equivalent to this:

foreign import log :: forall r. String -> Eff (console :: Unit | r) Unit

exports.log = function(string) {
  return function () {
    console.log(string);
  };
};

The only difference between unsafeForeignFunction and unsafeForeignProcedure is that the former takes an expression as its second argument, and the latter a statement.