Another gem from the past

The developer survey conducted by Stack Overflow is a point of reference for many businesses. It is also one of the most followed surveys by the professionals alike. In 2024 the survey reported Erlang developers are paid higher salary. That said we focus on the language itself in this dispatch.

This language was designed to be used for real time applications. Those with a low latency response. Like many programming languages of those days, Erlang is function oriented. In the modern days popular chatting application WhatsApp is built using Erlang. Similarly, AWS and many Message Queue applications also built using Erlang. Key features that make this language the diamond in the rough are its features of concurrency, code swapping (!), message passing etc. Amongst these the code swapping feature is the most admirable one that we love. In this feature we could swap the system code without a down time! Did that rise your eyebrows? It did for us.

The famous way to kickstart any programming language is with a hello world. Here it goes.

-module(hello).

-export([greet/0]).

greet() ->

? ? io:format(“Hello world!~n”).

The way to compile this is simple as?

c(hello).

You must do this within the Erlang shell.

Once this finishes successfully, we can invoke the result of compilation as;

hello:greet()

Where the first word is for the module and the next word is for the function that was exported.

Basics

Unlike the object-oriented compiled languages, most of functional languages are dynamically typed. Thus, there is no vast type system in Erlang. It also plays in benefit of being a fast system. The few that are known in Erlang are –

exampleOfTuple = {“hello”, “again”, 3}.

exampleOfList = [42, 2005, {“hello”, “again”}].

exampleOfMap = #{sender=>”Jack”, messages=> 24}

Let us look at a another simple yet convoluted type;

-module(conversion).

-export([convert/2]).

convert(value, inch) ->

? ? value/2.54.

convert(value, centimeters) ->

? ? value * 2.54.

The literals inch and centimeters are the types which is used to do some what similar overriding. They are called Atoms in the language.

Next we look at some control having learnt the basics. The corner stone of control is the if condition which is written as

case omega of?

? ? 1.52 -> controlMeasure:triggerReserve();

? ? 2.45 -> controlMeasure:fillReserve();

? ? _ -> controllMeasure:releaseDelta();

end.

This is familiar to the swith..case which is an advanced form of if..else. If you have not noticed another similarity with the languages of those days. It is the blend of natural language English into programming. Did you notice the period kept at the end of the line. It is the terminator which in many programming languages is “;”.

That is much about control, we cannot miss out on mentioning about higher order functions, a key tennet of modern-day functional programming languages.

converter = fun(x) -> x*4 end.

converter(10).

This can be invoked directly from Erlang shell. We are assigning a container for a higher order function. Remember Erlang shell knows nothing but function. The token “converter” is a function and it trickles down the parameter to its assignment.

This is all one experienced professional will need to get started with Erlang. To build a system there is more than these basics. But they build upon these. Concepts of processes, message passing and error handling are very essential to building a robust system.

As much as the carrot of higher pay may attract talent to Erlang; we wish the real value surfaces up as such long bygone gem of a language is polished by the present generation to solve day-to-day problems. Very much like reliable messaging between two friends (read WhatsApp).