ReasonML Quick Start Guide

Would this work with normal variants?

Let's try to do this with normal variants and see what happens:

type validArgs =   | Int(int)  | Str(string);[@bs.val] external dynamic : validArgs => string = "";dynamic(Int(1));

The problem with the preceding implementation is that Int(1) does not compile to a JavaScript number. Normal variants are compiled to an array and our dynamic function returns undefined instead of "Number: 42". The function returns undefined because no cases on the switch statement were matched.

With polymorphic variants, BuckleScript compiles dynamic(`Int(42)) to dynamic(42) and the function works as expected.