# Bitmasks

Bitmasks for boolean flags.

## Usage

Define your flags as an enumeration:

```haskell
import Data.Word
import Data.Bitmask

data PizzaTopping =
    Cheese
  | Mushrooms
  | Pineapple
  | Ham
  deriving (Show, Eq, Bounded, Enum)

-- We only need 8 bits since there are only 4 toppings
type PizzaMask = Bitmask8 PizzaTopping
```

### Creating bitmasks

```haskell
-- A Margherita pizza (cheese only)
margherita :: PizzaMask
margherita = fromFlags [Cheese]

veggie :: PizzaMask
veggie = fromExceptFlags [Ham]

```

### Access and modify flags

Use `getFlag` to check if a pizza has a specific topping:

```haskell
>>> getFlag Cheese funghi
True
>>> getFlag Pineapple funghi
False
```

Add toppings to a pizza:

```haskell
>>> hawaiian = addFlags [Pineapple, Ham] margherita
>>> getFlags [Pineapple, Mushroom] hawaiian
True
```

Make any pizza vegetarian (bitwise AND):

```haskell
>>> veggieHawaiian = veggie .&. hawaiian
>>> getFlag Ham veggieHawaiian
```

Toggle (I have no idea what I'm talking about) the toppings :

```haskell
>>> funghi = flipFlags [Pineapple, Mushroom] veggieHawaiian
>>> toFlags funghi
[Cheese,Mushrooms]
```

Remove a topping:

```haskell
>>> margherita == deleteFlag Mushroom funghi
True
```

### Convert to lists

```haskell
-- Get all toppings as a list
>>> toFlags funghi
[Cheese,Mushrooms]
>>> toFlags hawaiian
[Cheese,Pineapple,Ham]

-- Convert to association lists
>>> toFlagsBool funghi
[(Cheese,True),(Mushrooms,True),(Pineapple,False),(Ham,False)]
```