<p>Anonymous functions and closures are a useful concepts included in most modern
programming languages. Like so many elements of modern programming the closure
has its origins in the <a href="http://letoverlambda.com/index.cl/guest/chap2.html">early Lisps</a>.</p>

<p>Anonymous functions are used heavily in JavaScript for…</p>

<p><a href="http://en.wikipedia.org/wiki/SOLID_(object-oriented_design)">SOLID</a> is an acronym created by <a href="http://en.wikipedia.org/wiki/Robert_Cecil_Martin">Bob
Martin</a> and <a href="https://twitter.com/mfeathers">Michael
Feathers</a> that refers to five fundamental
principles that help engineers write maintainable code. We like to think of these
principles as the foundational elements we use when evaluating the health…</p>

<p>Regular expressions have been around since the early days of computer
science. They gained widespread adoption with the introduction of Unix. A
regular expression is a notation for describing sets of character strings. They
are used to identify patterns…</p>

<p>Almost all applications store data in one format or another somewhere. Us
developers spend a lot of time thinking about our data. In a most cases we end
up storing that data in a relational database. The advent of the
<a href="http://en.wikipedia.org/wiki/Object-relational_mapping">ORM</a> has made writing
raw SQL…</p>

<p>The value of unit tests and TDD are well documented. Unfortunately, it’s still
daunting to start practicing it. Here’s a primer.</p>

<h2 id="our-desired-code">Our desired code</h2>

<p>We need to write a method that:</p>

<ul>
<li>takes a string as an argument</li>
<li>reverses the string</li>
<li>saves the string…</li>
</ul>

<blockquote>
<p><a href="http://www.stroustrup.com/glossary.html#Gpolymorphism">Polymorphism</a>
- the provision of a single interface to entities of different types</p>
</blockquote>

<p>Polymorphism is one of the fundamental features of object oriented programming, but what
exactly does it mean? At its core, in Ruby, it means being able to send…</p>