innoave / bounded-number

A type representing a bounded number

Bounded Number

The type Bounded number represent a number bounded between a minimum and a maximum.

Once the bounds are set the value of a bounded number can not get greater than its max bound neither can it get lower than its min bound.

Functions that modify the value of a bound number come in two variants.

1. The normal variant clips the resulting value within the defined bounds. Functions of this variant are inc, dec, incBy, decBy, set and map.

   Bounded.between 0 10
       --|> Expect.equal 0 << Bounded.value
       |> Bounded.incBy 2
       --|> Expect.equal 2 << Bounded.value
       |> Bounded.incBy 9
       --|> Expect.equal 10 << Bounded.value

2. The trying variant explicitly states whether the result would overrun the defined bounds by returning a Maybe. These are functions which names are prefixed with "try" like tryInc, tryDec, trySet, tryMap.

   Bounded.between 0 10
       --|> Expect.equal 0 << Bounded.value
       |> Bounded.tryIncBy 2
       --|> Expect.equal (Just 2) << Bounded.value
       |> Bounded.tryIncBy 9
       --|> Expect.equal Nothing << Bounded.value

The value of a bounded number can be set directly by the set function and read using the value function.

Bounded.between 0 10
    |> Bounded.set 4
    |> Bounded.value
    --|> Expect.equal 4

The functions encode and decoder support a default JSON representation of a bounded number.

Check out the documentation of the functions as well as the fairly complete unit tests.