This might be a good time to check out algebraic data types, esp. with a single constructor. For example, in Elm you might declare: type Length = Inches In

This might be a good time to check out algebraic data types, esp. with a single constructor. For example, in Elm you might declare: type Length = Inches Int Then any function that accepts a Length, you can only pass in a length. This effectively acts like tagged tuples verified at compile time. You can later extend this type to be: type Length = Inches Int | Meters Int and any code that reads length would have to handle both cases (also checked at compile that). I have found this to be a great way of ensuring all of your types are correct (and sometimes, a great frustration of wishing I didn't have to wrap/unwrap types so often).