Web Development with ReasonML

Switching to fun

If you have a function that consists solely of a switch expression, you can write it using the keyword fun without needing to give a parameter. The following two functions do the same thing:

miscellanea/misc/src/Shortcuts.re

let recip1 = (x: float): option(float) =>
  switch (x) {
    | 0.0 => None
    | x => Some(1.0 /. x)
  };

let recip2 = fun
  | 0.0 => None
  | x => Some(1.0 /. x);

This only works if the switch expression is a simple variable. You can’t convert the following switch to fun:

miscellanea/misc/src/Shortcuts.re

let toFloat = (s:string): option(float) => {
  switch (float_of_string(s)) {
    | result => Some(result)
    | exception(