# Allergies

Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.

An allergy test produces a single numeric score which contains the
information about all the allergies the person has (that they were
tested for).

The list of items (and their value) that were tested are:

* eggs (1)
* peanuts (2)
* shellfish (4)
* strawberries (8)
* tomatoes (16)
* chocolate (32)
* pollen (64)
* cats (128)

So if Tom is allergic to peanuts and chocolate, he gets a score of 34.

Now, given just that score of 34, your program should be able to say:

- Whether Tom is allergic to any one of those allergens listed above.
- All the allergens Tom is allergic to.

Note: a given score may include allergens **not** listed above (i.e.
allergens that score 256, 512, 1024, etc.).  Your program should
ignore those components of the score.  For example, if the allergy
score is 257, your program should only report the eggs (1) allergy.


## Hints

To complete this exercise you need to to create the data type `Allergen`,
with `Eq` and `Show` instances, and implement the following functions:

- `allergies`
- `isAllergicTo`

You will find a dummy data declaration and type signatures already in place,
but it is up to you to define the functions and create a meaningful data type,
newtype or type synonym.



## Getting Started

For installation and learning resources, refer to the
[exercism help page](http://exercism.io/languages/haskell).

## Running the tests

To run the test suite, execute the following command:

```bash
stack test
```

#### If you get an error message like this...

```
No .cabal file found in directory
```

You are probably running an old stack version and need
to upgrade it.

#### Otherwise, if you get an error message like this...

```
No compiler found, expected minor version match with...
Try running "stack setup" to install the correct GHC...
```

Just do as it says and it will download and install
the correct compiler version:

```bash
stack setup
```

## Running *GHCi*

If you want to play with your solution in GHCi, just run the command:

```bash
stack ghci
```

## Feedback, Issues, Pull Requests

The [exercism/haskell](https://github.com/exercism/haskell) repository on
GitHub is the home for all of the Haskell exercises.

If you have feedback about an exercise, or want to help implementing a new
one, head over there and create an issue.  We'll do our best to help you!

## Source

Jumpstart Lab Warm-up [http://jumpstartlab.com](http://jumpstartlab.com)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.