Elixir 1. General language features and variables

Elixir is a High Level, Dynamic, Functional Programming language based on Erlang Development Platform. Erlang is designed to create scalable, distributed, and fault-tolerant systems. Elixir is a modern replacement for Erlang Programming language which also runs on Erlang VM. Both language are inter compatible and can easily share libraries.

The Elixir Programming language

The Elixir programming language is more compact, clean and easy to write and maintain.

Today we are going to start a tour of elixir language, these are my notes while learning elixir from the book "Elixir in Action, Second Edition" by Sasa Juric. I have always used conventional note book for writing technical notes, mainly notes when learning new programming language and i think they are not that useful, hence this is me trying to take notes on Obsidian and later publish on my blog.

Note: This is not a guide, nor a tutorial, it is just what i may have written in my note book, so these are think form the language which i kept for future reference, i.e this series will mostly contain nontrivial concepts and constructs.

Here is the beautiful book cover picture.

I am pretty sure that this will be more usable and effective that note books, because i find my self writing lots of notes in my GitHub Gist, from which i take reference a lot.

So lets start

Installation

Elixir can be installed from the official installation guide , what i have seen is for most (if not all) OS have elixir package for elixir.

For me, on Arch linux, the command is

sudo pacman -s elixir

This will install both elixir and erlang. As elixir will run on Erlang VM, called as BEAM, we also need Erlang on the system.

Interactive Shell

elixir comes with an interactive shell like node, python and many more, which can be starting by running iex (interactive elixir).

iex

for me, i can see something like this.

$ iex
Erlang/OTP 26 [erts-14.0.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit:ns]
 
Interactive Elixir (1.15.0) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)>

see i am using Erlang version 26 and Elixir version 1.15.0.

Running iex starts an instance of the BEAM and then starts an interactive Elixir shell inside it.

Now we can execute an expression by directly typing on shell.

iex(3)> 1 + 2
3
iex(4)>

here 1 + 2 is an expression which resulted in 3 .

Note: Everything in Elixir is an expression, even if and case.

I think this is because Elixir is a functional programming language, so passing of data between functions is very important as the data is itself is immutable

Any valid elixir code can be executed in the shell, even multi line commands,

iex(7)> 1 + (
...(7)>   2 * 3
...(7)> ) / 4
2.5
iex(8)>

• iex is provided by a module called IEx

iex(9)> h IEx

Variables

iex(7)> my_name = "Kunal Singh"
"Kunal Singh"
iex(8)> my_name = 20
20
iex(9)> my_name
20
iex(10)> my_name = [1, 2, 3]
[1, 2, 3]
iex(11)> my_name
[1, 2, 3]
iex(12)>

• Dynamic Type

In Elixir terms, assignment is called Binding. When you initialize a variable with a value, the variable is bound to that value.

Variables name

valid_variable_name
also_valid_1
validButNotRecommended
NotValid

variable names can end with a ? and !,

what!

iex(1)> a? = "A"
"A"
iex(2)> b! = "B"
"B"
iex(3)> a?
"A"
iex(4)> b!
"B"
iex(5)>

About Rebinding (reassigning) variables

Rebinding doesn’t mutate the existing memory location. It reserves new memory and reassigns the symbolic name to the new location.

Because here (in erlang / elixir eco) data is immutable

Elixir is a Garbage Collected language, which will clean all these memory allocation, without any manual maneuver.

I have mixed feeling about this, as language like Rust handle memory without garbage collector, which increases the performance of the language.