Why doesn’t ReasonML have nullary functions? That is due to ReasonML always performing partial application (explained in detail later): If you don’t provide all of a function’s parameters, you get a new function from the remaining parameters to the result. As a consequence, if you could actually provide no parameters at all, then func() would be the same as func and neither would actually call func.

– Exploring ReasonML and functional programming by Dr. Axel Rauschmayer

Posted first at hoichi.io, because you can’t be too paranoid.