ProgrammingElixirBook

Step #1 of my Learning Elixir journey is complete.

I had expected to mostly read and instead I worked through most of the exercises.

A useful first step:

• The Elixir syntax no longer looks quite so foreign.
• Pattern matching caused a fundamental shift in how I think about writing functions.
• I’m confident I can write and deploy a simple application.
• I have a reasonable understanding of message passing.
• Still lots of practice mapping and reducing.
• Actors!

I appreciate the positive feedback I’ve received from my posts. The primary audience for these posts is myself, to keep myself motivated and gauge my progress.

Still lots to learn, the dance continues and yes, Dave, I did have fun. Thank you.

Programming Elixir ≥1.6: Functional |> Concurrent |> Pragmatic |> Fun by Dave Thomas.

Some of Dave’s words I found particularly interesting, insightful, or inspiring.

“But mostly, I want you to have fun.”

“…you can think about programming in a different way.”

“You no longer have to think too hard about protecting your data consistency in a multithreaded environment.”

“I don’t want to hide data. I want to transform it.”

Writing Your Own Sigils

1. Lowercase sigils interpolate their parameters, uppercase sigils do not.

2. User-defined sigils are not globally available. Need to be imported. Reduces the risk of running into a system-defined sigil.

Protocols remind me of Python’s duck typing.

An Elixir behaviour is a list of functions a module is expected to implement.

My interest is in application development so macros are not something I expect to ever be creating. So this is mostly a chapter for reading.

Did work through the first two exercises. Took awhile for me to understand that I cannot use a macro-defined function in the module where it was expanded. Makes sense since Elixir first compiles then loads, so the dynamically-created function isn’t available for use.

Agents are processes that maintain state. Effectively, this is wrapping the Stack.Stash process we’ve implemented earlier.

Ran into significant issues between outdated Distillery information and incompatibility with OTP 25.

A day for reading and playing with Dave’s code. I’ll be keeping the duper source around for future reference to starting multiple servers.

In order to reliably remember a value, we spin up a process that does nothing except remembering. This isolates the information storage, which has maximal reliability, from information manipulation, which can have all sorts of problems.