Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Newsletter Hub
Free Learning
Arrow right icon
timer SALE ENDS IN
0 Days
:
00 Hours
:
00 Minutes
:
00 Seconds
Learning Elixir
Learning Elixir

Learning Elixir: Unveil many hidden gems of programming functionally by taking the foundational steps with Elixir

Arrow left icon
Profile Icon Kenny Ballou Profile Icon Kenneth Ballou
Arrow right icon
Free Trial
Full star icon Full star icon Full star icon Full star icon Full star icon 5 (1 Ratings)
Paperback Jan 2016 286 pages 1st Edition
eBook
zł59.99 zł125.99
Paperback
zł157.99
Subscription
Free Trial
Arrow left icon
Profile Icon Kenny Ballou Profile Icon Kenneth Ballou
Arrow right icon
Free Trial
Full star icon Full star icon Full star icon Full star icon Full star icon 5 (1 Ratings)
Paperback Jan 2016 286 pages 1st Edition
eBook
zł59.99 zł125.99
Paperback
zł157.99
Subscription
Free Trial
eBook
zł59.99 zł125.99
Paperback
zł157.99
Subscription
Free Trial

What do you get with a Packt Subscription?

Free for first 7 days. $19.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing
Table of content icon View table of contents Preview book icon Preview Book

Learning Elixir

Chapter 2. Elixir Basics – Foundational Steps toward Functional Programming

In the previous chapter, we talked about functional programming, installed Elixir, and tried a few elementary examples.

In this chapter, we are going to go into depth on the syntax and basic built-in types and operators of Elixir (and implicitly, Erlang). We are going to explore some more structural elements of Elixir code and begin our discussion of pattern matching.

Everything is an expression

We have hinted at this concept in the previous chapter, but let's discuss it in more detail here.

In Elixir, there are no statements. Everything is an expression. Let's break this down. Statements typically refer to instructions where the programmer specifies to the computer or runtime to perform some action. This action could, for example, add two numbers together and assign the value to a variable. Or, it could instruct the machine to print data—strings, numbers, and bits—to the console. Or, it could instruct the machine to make a remote connection to another machine and request a web page. These actions may have ephemeral results—the value of the variable, output text on the screen, and page data from the request. But in all of these examples, the code, itself, which instructs the performance of such actions, does not necessarily, nor inherently return anything.

To contrast this to expressions, we note that we can still do all...

A short introduction to types

Like most programming languages, Elixir has its fair share of numerical, boolean, character, and collection types. It also has some extra types, namely, atoms and binaries. In this chapter, we will see how all of these types work. However, let's start our discussion with numerical types.

Numerical types

Numerical types include the obvious integers. For example, in the interactive prompt (iex), we can enter a few basic numbers:

iex(1)> 42
42

We can also do some basic arithmetic with numbers, of course:

iex(2)> 42 + 5
47
iex(3)> 6 * 7
42
iex(4)> 42 - 10
32
iex(5) 42 / 6
7.0

So, addition, subtraction, and multiplication work as we expect. Division, however, did what is typically called implicit type widening or implicit type casting. That is, we took two integer types and converted it into a floating type through division. In fact, the / operator will always return a floating point type. If you want an integer type back, you can use the div and rem...

Invariable variables and pattern matching

One of the most misunderstood concepts in functional programming is that of assignment. Or, said another way, assignment doesn't exist.

Let's try to dispel this misconceived idea. In iex, we might see some code like this:

iex(1)> a = 2
2
iex(2)> a + 4
6

We may be tempted to explain the preceding code snippet with something like, "So we assign 2 to a and then add 4 to a giving us 6." However, in Elixir, this is incorrect. Elixir does not define = as an assignment operator, but rather a match operator. That is, Elixir attempts to match the left side of the = operator to that of the right.

In step 1, for Elixir to make the match succeed, we bind the value of 2 to the variable, a. Then later, when we perform the addition, we are substituting 2 for a, yielding an expression that looks like 2 + 4, which obviously equals 6.

This is a really different way to think about what is going on internally. Take a moment to let it sink in.

Back...

Elixir structure

So far, we haven't seen much more than tiny snippets, demonstrating a fraction of the syntax of Elixir. Now we are going to go into more detail and look at some more in-depth examples.

We will start with what may be considered a functional language's real "hello world", the map function.

Note

Note that this example will use some concepts that we are going to go into more detail in the next few chapters.

The map function essentially takes a function and a list, and applies the function to each element in the list. Ideally, the application of one element in the list does not depend or effect any other application of any other element. Thus, this is usually something that can be trivial (in concept) to parallelize. However, very few languages make it so easy as the functional languages, and in particular, Elixir.

Using what we know now (and some stuff we haven't covered), here's how we might write our own map function:

defmodule MyMap do
  def map(...

Elixir files

Elixir uses two files, .ex for compiled code and .exs for scripts. They must both be UTF-8 encoded. We will go over .ex some more when we introduce mix in the next chapter. But for now, let's discuss .exs a little more.

We can write all the Elixir code we have shown so far into a script (we won't though, there is just a small subset) and then we can use the interactive interpreter to load up our script and run it.

For example, we can put the MyMap code from earlier into a script:

defmodule MyMap do
  def map([], _) do
    []
  end

  def map([h|t], f) do
    [f.(h) | map(t, f)]
  end
end

square = fn x -> x * x end
MyMap.map([1, 2, 3, 4, 5], square)

Go ahead and save it as mymap.exs. Launch a terminal and use the cd command to navigate to the directory that you saved your script in and then launch iex.

Once in iex, we will use import_file/1 to import and launch our script.

In your iex, type h(import_file/1) to get the documentation of import_file/1:

iex(1)> h(import_file...

Everything is an expression


We have hinted at this concept in the previous chapter, but let's discuss it in more detail here.

In Elixir, there are no statements. Everything is an expression. Let's break this down. Statements typically refer to instructions where the programmer specifies to the computer or runtime to perform some action. This action could, for example, add two numbers together and assign the value to a variable. Or, it could instruct the machine to print data—strings, numbers, and bits—to the console. Or, it could instruct the machine to make a remote connection to another machine and request a web page. These actions may have ephemeral results—the value of the variable, output text on the screen, and page data from the request. But in all of these examples, the code, itself, which instructs the performance of such actions, does not necessarily, nor inherently return anything.

To contrast this to expressions, we note that we can still do all of these things, however, each instruction...

A short introduction to types


Like most programming languages, Elixir has its fair share of numerical, boolean, character, and collection types. It also has some extra types, namely, atoms and binaries. In this chapter, we will see how all of these types work. However, let's start our discussion with numerical types.

Numerical types

Numerical types include the obvious integers. For example, in the interactive prompt (iex), we can enter a few basic numbers:

iex(1)> 42
42

We can also do some basic arithmetic with numbers, of course:

iex(2)> 42 + 5
47
iex(3)> 6 * 7
42
iex(4)> 42 - 10
32
iex(5) 42 / 6
7.0

So, addition, subtraction, and multiplication work as we expect. Division, however, did what is typically called implicit type widening or implicit type casting. That is, we took two integer types and converted it into a floating type through division. In fact, the / operator will always return a floating point type. If you want an integer type back, you can use the div and rem functions...

Left arrow icon Right arrow icon

Key benefits

  • Explore the functional paradigms of programming with Elixir through use of helpful examples
  • Concise step-by-step instructions to teach you difficult technical concepts
  • Bridge the gap between functional programming and Elixir

Description

Elixir, based on Erlang’s virtual machine and ecosystem, makes it easier to achieve scalability, concurrency, fault tolerance, and high availability goals that are pursued by developers using any programming language or programming paradigm. Elixir is a modern programming language that utilizes the benefits offered by Erlang VM without really incorporating the complex syntaxes of Erlang. Learning to program using Elixir will teach many things that are very beneficial to programming as a craft, even if at the end of the day, the programmer isn't using Elixir. This book will teach you concepts and principles important to any complex, scalable, and resilient application. Mostly, applications are historically difficult to reason about, but using the concepts in this book, they will become easy and enjoyable. It will teach you the functional programing ropes, to enable them to create better and more scalable applications, and you will explore how Elixir can help you achieve new programming heights. You will also glean a firm understanding of basics of OTP and the available generic, provided functionality for creating resilient complex systems. Furthermore, you will learn the basics of metaprogramming: modifying and extending Elixir to suite your needs.

Who is this book for?

This book targets developers new to Elixir, as well as Erlang, in order to make them feel comfortable in functional programming with Elixir, thus enabling them to develop more scalable and fault-tolerant applications. Although no knowledge of Elixir is assumed, some programming experience with mainstream Object-Oriented programming languages such a Ruby, Python, Java, C# would be beneficial.

What you will learn

  • Explore Elixir to create resilient, scalable applications
  • Create fault-tolerant applications
  • Become better acquainted with Elixir code and see how it is structured to build and develop functional programs
  • Learn the basics of functional programming
  • Gain an understanding of effective OTP principles
  • Design program-distributed applications and systems
  • Write and create branching statements in Elixir
  • Learn to do more with less using Elixir s metaprogramming
  • Be familiar with the facilities Elixir provides for metaprogramming, macros, and extending the Elixir language

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Jan 05, 2016
Length: 286 pages
Edition : 1st
Language : English
ISBN-13 : 9781785881749
Category :
Languages :

What do you get with a Packt Subscription?

Free for first 7 days. $19.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing

Product Details

Publication date : Jan 05, 2016
Length: 286 pages
Edition : 1st
Language : English
ISBN-13 : 9781785881749
Category :
Languages :

Packt Subscriptions

See our plans and pricing
Modal Close icon
$19.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
$199.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just zł20 each
Feature tick icon Exclusive print discounts
$279.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just zł20 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total 553.97
Mastering Elixir
zł197.99
Learning Elixir
zł157.99
Elixir Cookbook
zł197.99
Total 553.97 Stars icon

Table of Contents

10 Chapters
1. Introducing Elixir – Thinking Functionally Chevron down icon Chevron up icon
2. Elixir Basics – Foundational Steps toward Functional Programming Chevron down icon Chevron up icon
3. Modules and Functions – Creating Functional Building Blocks Chevron down icon Chevron up icon
4. Collections and Stream Processing Chevron down icon Chevron up icon
5. Control Flow – Occasionally You Need to Branch Chevron down icon Chevron up icon
6. Concurrent Programming – Using Processes to Conquer Concurrency Chevron down icon Chevron up icon
7. OTP – A Poor Name for a Rich Framework Chevron down icon Chevron up icon
8. Distributed Elixir – Taking Concurrency to the Next Node Chevron down icon Chevron up icon
9. Metaprogramming – Doing More with Less Chevron down icon Chevron up icon
Index Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Full star icon Full star icon 5
(1 Ratings)
5 star 100%
4 star 0%
3 star 0%
2 star 0%
1 star 0%
Mr. T. Browne May 25, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
I really like this book because if fits my brain better than all the other Elixir books (I own, literally, all of them). This one is great because it's ultra simple, but also does not assume that you're a complete programming newby. It doesn't go into long detail about what a linked list actually is, for example. It just tells you that Elixir has linked lists (denoted by [x, x, x]). It assumes you know what a linked list is, and its O(n) seek characteristics. Basically this is a very good book if you're coming from another (traditional) programming language. It's gentle with the functional aspects and the syntax, but it's not pedantic and long winded on computer science concepts -> it assumes you're familiar with stuff already.I also like the more "conceptual" approach that this book takes, rather than diving into some irrelevant "project" that gets filled out chapter by chapter as the Pragmatic Programmers books tend to do. It speaks to the design oriented mind, as opposed to the osmosis-oriented mind.
Amazon Verified review Amazon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is included in a Packt subscription? Chevron down icon Chevron up icon

A subscription provides you with full access to view all Packt and licnesed content online, this includes exclusive access to Early Access titles. Depending on the tier chosen you can also earn credits and discounts to use for owning content

How can I cancel my subscription? Chevron down icon Chevron up icon

To cancel your subscription with us simply go to the account page - found in the top right of the page or at https://subscription.packtpub.com/my-account/subscription - From here you will see the ‘cancel subscription’ button in the grey box with your subscription information in.

What are credits? Chevron down icon Chevron up icon

Credits can be earned from reading 40 section of any title within the payment cycle - a month starting from the day of subscription payment. You also earn a Credit every month if you subscribe to our annual or 18 month plans. Credits can be used to buy books DRM free, the same way that you would pay for a book. Your credits can be found in the subscription homepage - subscription.packtpub.com - clicking on ‘the my’ library dropdown and selecting ‘credits’.

What happens if an Early Access Course is cancelled? Chevron down icon Chevron up icon

Projects are rarely cancelled, but sometimes it's unavoidable. If an Early Access course is cancelled or excessively delayed, you can exchange your purchase for another course. For further details, please contact us here.

Where can I send feedback about an Early Access title? Chevron down icon Chevron up icon

If you have any feedback about the product you're reading, or Early Access in general, then please fill out a contact form here and we'll make sure the feedback gets to the right team. 

Can I download the code files for Early Access titles? Chevron down icon Chevron up icon

We try to ensure that all books in Early Access have code available to use, download, and fork on GitHub. This helps us be more agile in the development of the book, and helps keep the often changing code base of new versions and new technologies as up to date as possible. Unfortunately, however, there will be rare cases when it is not possible for us to have downloadable code samples available until publication.

When we publish the book, the code files will also be available to download from the Packt website.

How accurate is the publication date? Chevron down icon Chevron up icon

The publication date is as accurate as we can be at any point in the project. Unfortunately, delays can happen. Often those delays are out of our control, such as changes to the technology code base or delays in the tech release. We do our best to give you an accurate estimate of the publication date at any given time, and as more chapters are delivered, the more accurate the delivery date will become.

How will I know when new chapters are ready? Chevron down icon Chevron up icon

We'll let you know every time there has been an update to a course that you've bought in Early Access. You'll get an email to let you know there has been a new chapter, or a change to a previous chapter. The new chapters are automatically added to your account, so you can also check back there any time you're ready and download or read them online.

I am a Packt subscriber, do I get Early Access? Chevron down icon Chevron up icon

Yes, all Early Access content is fully available through your subscription. You will need to have a paid for or active trial subscription in order to access all titles.

How is Early Access delivered? Chevron down icon Chevron up icon

Early Access is currently only available as a PDF or through our online reader. As we make changes or add new chapters, the files in your Packt account will be updated so you can download them again or view them online immediately.

How do I buy Early Access content? Chevron down icon Chevron up icon

Early Access is a way of us getting our content to you quicker, but the method of buying the Early Access course is still the same. Just find the course you want to buy, go through the check-out steps, and you’ll get a confirmation email from us with information and a link to the relevant Early Access courses.

What is Early Access? Chevron down icon Chevron up icon

Keeping up to date with the latest technology is difficult; new versions, new frameworks, new techniques. This feature gives you a head-start to our content, as it's being created. With Early Access you'll receive each chapter as it's written, and get regular updates throughout the product's development, as well as the final course as soon as it's ready.We created Early Access as a means of giving you the information you need, as soon as it's available. As we go through the process of developing a course, 99% of it can be ready but we can't publish until that last 1% falls in to place. Early Access helps to unlock the potential of our content early, to help you start your learning when you need it most. You not only get access to every chapter as it's delivered, edited, and updated, but you'll also get the finalized, DRM-free product to download in any format you want when it's published. As a member of Packt, you'll also be eligible for our exclusive offers, including a free course every day, and discounts on new and popular titles.