# Etl

We are going to do the `Transform` step of an Extract-Transform-Load.

### ETL
Extract-Transform-Load (ETL) is a fancy way of saying, "We have some crufty, legacy data over in this system, and now we need it in this shiny new system over here, so
we're going to migrate this."

(Typically, this is followed by, "We're only going to need to run this
once." That's then typically followed by much forehead slapping and
moaning about how stupid we could possibly be.)

### The goal
We're going to extract some scrabble scores from a legacy system.

The old system stored a list of letters per score:

- 1 point: "A", "E", "I", "O", "U", "L", "N", "R", "S", "T",
- 2 points: "D", "G",
- 3 points: "B", "C", "M", "P",
- 4 points: "F", "H", "V", "W", "Y",
- 5 points: "K",
- 8 points: "J", "X",
- 10 points: "Q", "Z",

The shiny new scrabble system instead stores the score per letter, which
makes it much faster and easier to calculate the score for a word. It
also stores the letters in lower-case regardless of the case of the
input letters:

- "a" is worth 1 point.
- "b" is worth 3 points.
- "c" is worth 3 points.
- "d" is worth 2 points.
- Etc.

Your mission, should you choose to accept it, is to transform the legacy data
format to the shiny new format.

### Notes

A final note about scoring, Scrabble is played around the world in a
variety of languages, each with its own unique scoring table. For
example, an "E" is scored at 2 in the Māori-language version of the
game while being scored at 4 in the Hawaiian-language version.

## Running tests

In order to run the tests, issue the following command from the exercise
directory:

For running the tests provided, `rebar3` is used as it is the official build and
dependency management tool for erlang now. Please refer to [the tracks installation
instructions](http://exercism.io/languages/erlang/installation) on how to do that.

In order to run the tests, you can issue the following command from the exercise
directory.

```bash
$ rebar3 eunit
```

### Test versioning

Each problem defines a macro `TEST_VERSION` in the test file and
verifies that the solution defines and exports a function `test_version`
returning that same value.

To make tests pass, add the following to your solution:

```erlang
-export([test_version/0]).

test_version() ->
  1.
```

The benefit of this is that reviewers can see against which test version
an iteration was written if, for example, a previously posted solution
does not solve the current problem or passes current tests.

## Questions?

For detailed information about the Erlang track, please refer to the
[help page](http://exercism.io/languages/erlang) on the Exercism site.
This covers the basic information on setting up the development
environment expected by the exercises.

## Source

The Jumpstart Lab team [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.