Dave Thomas - Programming Elixir: Functional |> Concurrent |> Pragmatic |> Fun

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ISBN-13: 978-1-937785-58-1

Book version: P1.0October, 2014

I have always been fascinated with how changes in hardware affect howwe write software.

A couple of decades ago, memory was a very limited resource. It madesense back then for our software to take hold of some piece ofmemory and mutate it as necessary. However, allocating this memory andcleaning up after we no longer needed it was a very error-pronetask. Some memory was never freed; sometimes memory was allocated overanother structure, leading to faults. At the time, garbage collectionwas a known technique, but we needed faster CPUs in order to use it inour daily software and free ourselves from manual memorymanagement. That has happenedmost of our languages are nowgarbage-collected.

Today, a similar phenomenon is happening. Our CPUs are not getting anyfaster. Instead, our computers get more and more cores. This means new software needs to use as many cores as it can if it is to maximizeits use of the machine. This conflicts directly with how we currently writesoftware.

In fact, mutating our memory state actually slows down our softwarewhen many cores are involved. If you have four cores trying to accessand manipulate the same piece of memory, they can trip over eachother. This potentially corrupts memory unless some kind ofsynchronization is applied.

I quickly learned that applying this synchronization is manual, errorprone, and tiresome, and it hurts performance. I suddenly realized thats nothow I wanted to spend time writing software in the next years of mycareer, and I set out to study new languages and technologies.

It was on this quest that I fell in love with the Erlang virtualmachine and ecosystem.

In the Erlang VM, all code runs in tiny concurrent processes, each with its own state. Processes talk to each othervia messages. And since all communication happens by message-passing,exchanging messages between different machines on the same network ishandled transparently by the VM, making it a perfect environment forbuilding distributed software!

However, I felt there was still a gap in the Erlang ecosystem. I missedfirst-class support for some of the features I find necessary in mydaily work, things such as metaprogramming, polymorphism, andfirst-class tooling. From this need, Elixir was born.