Web Development with ReasonML

Currying: Handling One Argument at a Time

What would happen if we called the avg function but only gave it one argument? Surely we’d get some sort of error:

functions/src/Currying.re

let avg = (a: float, b: float) : float => {
  (a +. b) /. 2.0;
};

Js.log2("Average of 3 and 4", avg(3.0, 4.0));
Js.log2("Average of 3?!", avg(3.0));

code/functions> bsb -make-world
ninja: Entering directory `lib/bs'
[3/3] Building src/Currying.mlast.d
[1/1] Building src/Currying-Simplefunctions.cmj
code/functions> node src/Currying.bs.js
Average of 3 and 4 3.5
Average of 3?! function (param) {
        return avg(3.0, param);
      }

It compiles without errors, and when we run it, we get a function as output ...