# Space Age

Given an age in seconds, calculate how old someone would be on:

   - Earth: orbital period 365.25 Earth days, or 31557600 seconds
   - Mercury: orbital period 0.2408467 Earth years
   - Venus: orbital period 0.61519726 Earth years
   - Mars: orbital period 1.8808158 Earth years
   - Jupiter: orbital period 11.862615 Earth years
   - Saturn: orbital period 29.447498 Earth years
   - Uranus: orbital period 84.016846 Earth years
   - Neptune: orbital period 164.79132 Earth years

So if you were told someone were 1,000,000,000 seconds old, you should
be able to say that they're 31 Earth-years old.

If you're wondering why Pluto didn't make the cut, go watch [this
youtube video](http://www.youtube.com/watch?v=Z_2gbGXzFbs).

## Setup

Check out [Exercism Help](http://exercism.io/languages/lisp) for instructions to
get started writing Common Lisp. That page will explain how to install and setup
a Lisp implementation and how to run the tests.

## Formatting

While Common Lisp doesn't care about indentation and layout of code,
nor whether you use spaces or tabs, this is an important consideration
for submissions to exercism.io. Excercism.io's code widget cannot
handle mixing of tab and space characters well so using only spaces is recommended to make
the code more readable to the human reviewers. Please review your
editors settings on how to accomplish this. Below are instructions for
popular editors for Common Lisp.

### VIM

Use the following commands to ensure VIM uses only spaces for
indentation:

```vimscript
:set tabstop=2
:set shiftwidth=2
:set expandtab
```

(or as a oneliner `:set tabstop=2 shiftwidth=2 expandtab`). This can
be added to your `~/.vimrc` file to use it all the time.

### Emacs

Emacs is very well suited for editing Common Lisp and has many
powerful add-on packages available. The only thing that one needs to
do with a stock emacs to make it work well with exercism.io is to
evaluate the following code:

`(setq indent-tab-mode nil)`

This can be placed in your `~/.emacs` (or `~/.emacs.d/init.el`) in
order to have it set whenever Emacs is launched.

One suggested add-on for Emacs and Common Lisp is
[SLIME](https://github.com/slime/slime) which offers tight integration
with the REPL; making iterative coding and testing very easy.

## Source

Partially inspired by Chapter 1 in Chris Pine's online Learn to Program tutorial. [http://pine.fm/LearnToProgram/?Chapter=01](http://pine.fm/LearnToProgram/?Chapter=01)

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