# Roman Numerals

Write a function to convert from normal numbers to Roman Numerals.

The Romans were a clever bunch. They conquered most of Europe and ruled
it for hundreds of years. They invented concrete and straight roads and
even bikinis. One thing they never discovered though was the number
zero. This made writing and dating extensive histories of their exploits
slightly more challenging, but the system of numbers they came up with
is still in use today. For example the BBC uses Roman numerals to date
their programmes.

The Romans wrote numbers using letters - I, V, X, L, C, D, M. (notice
these letters have lots of straight lines and are hence easy to hack
into stone tablets).

```
 1  => I
10  => X
 7  => VII
```

There is no need to be able to convert numbers larger than about 3000.
(The Romans themselves didn't tend to go any higher)

Wikipedia says: Modern Roman numerals ... are written by expressing each
digit separately starting with the left most digit and skipping any
digit with a value of zero.

To see this in practice, consider the example of 1990.

In Roman numerals 1990 is MCMXC:

1000=M
900=CM
90=XC

2008 is written as MMVIII:

2000=MM
8=VIII

See also: http://www.novaroma.org/via_romana/numbers.html

## Getting Started

Make sure you have read [D page](http://exercism.io/languages/d) on
exercism.io.  This covers the basic information on setting up the development
environment expected by the exercises.

## Passing the Tests

Get the first test compiling, linking and passing by following the [three
rules of test-driven development](http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd).
Create just enough structure by declaring namespaces, functions, classes,
etc., to satisfy any compiler errors and get the test to fail.  Then write
just enough code to get the test to pass.  Once you've done that,
uncomment the next test by moving the following line past the next test.

```D
static if (all_tests_enabled)
```

This may result in compile errors as new constructs may be invoked that
you haven't yet declared or defined.  Again, fix the compile errors minimally
to get a failing test, then change the code minimally to pass the test,
refactor your implementation for readability and expressiveness and then
go on to the next test.

Try to use standard D facilities in preference to writing your own
low-level algorithms or facilities by hand.  [DRefLanguage](https://dlang.org/spec/spec.html)
and [DReference](https://dlang.org/phobos/index.html) are references to the D language and D standard library.


## Source

The Roman Numeral Kata [http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals](http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals)

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