# Nucleotide Count

Given a DNA string, compute how many times each nucleotide occurs in the string.

DNA is represented by an alphabet of the following symbols: 'A', 'C',
'G', and 'T'.

Each symbol represents a nucleotide, which is a fancy name for the
particular molecules that happen to make up a large part of DNA.

Shortest intro to biochemistry EVAR:

- twigs are to birds nests as
- nucleotides are to DNA and RNA as
- amino acids are to proteins as
- sugar is to starch as
- oh crap lipids

I'm not going to talk about lipids because they're crazy complex.

So back to nucleotides.

DNA contains four types of them: adenine (`A`), cytosine (`C`), guanine
(`G`), and thymine (`T`).

RNA contains a slightly different set of nucleotides, but we don't care
about that for now.

## 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

The Calculating DNA Nucleotides_problem at Rosalind [http://rosalind.info/problems/dna/](http://rosalind.info/problems/dna/)

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