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Learning Erlang (programming language)

I know very little about the Erlang programming language. This document will go over all of my knowledge of the Erlang programming language.

Hello World in Erlang

This is how you make a normal Hello World program in Erlang:

-module(hello_world).
-compile(export_all).
hello() ->
    io:format("hello world~n").

/!\ This example has not been tested yet, and may not work

Comments in Erlang

Comments in Erlang are the same as in languages like PostScript.

Single line comments

Single line comments in Erlang are written like so:

%% This is a single line comment

Multi-line comments

Erlang does not support multi-line comments.

Break keyword in Erlang

Erlang does not support the break keyword.

Factorials in Erlang

A factorial can be defined like so:

fac(0) -> 1;
%% if 0, return 1, semicolon means `else`

/!\ This example has not been tested yet, and may not work

Fibonacci sequence in Erlang

Here is an undocumented Fibonacci sequence program written in Erlang.

-module(series).
-export([fib/1]).

fib(0) -> 0;
fib(N) when N < 0 -> err_neg_val;
fib(N) when N < 3 -> 1;
fib(N) -> fib_int(N, 0, 1).

fib_int(1, _, B) -> B;
fib_int(N, A, B) -> fib_int(N-1, B, A+B).

/!\ This example has not been tested yet, and may not work

Modules in Erlang

Erlang programs are defined with the -module line at the beginning. This can be written like so:

-module(myModule)
-export(0)

myModule1():
    io:format("Erlang module").

/!\ This example has not been tested yet, and may not work

Other knowledge of the Erlang programming language

1. Erlang is a language by Joe Armstrong, Robert Virding, and Mike Williams

2. Erlang is not a semicolon and curly bracket language, but it is a semicolon language

3. Erlang uses the *.erl file extension by default.

4. Erlang also uses the *.hrl file extension

5. Erlang originally was a proprietary language, but was later made open source

6. Erlang is used in the development of WhatsApp

7. Erlang was created in 1986

8. Erlang is not one of the top 50 programming languages (as of 2022, July 31st, it has never ranked 50 or higher on the TIOBE index, but it has ranked in the top 100) source: TIOBE index

9. Erlang is a language recognized by GitHub (as of 2022, Tuesday, August 2nd)

10. Erlang is a "let it crash" styled langaueg

11. No other knowledge of the Erlang programming language

Additional comments

1. I have not yet memorized the names of the developers

2. No other additional comments available

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File info

File type: Markdown document (*.md *.mkd *.mdown *.markdown)

File version: 1 (2022, Tuesday, August 2nd at 4:23 pm PST)

Line count (including blank lines and compiler line): 180

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File history

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Version 1 (2022, Tuesday, August 2nd at 4:23 pm PST)

Changes:

• Started the file

• Added the title section

• Added the Hello World in Erlang section

• Added the Object Oriented Hello World in Erlang section

• Added the Comments in Erlang section

• Added the Single line comments subsection

• Added the Multi-line comments subsection

• Added the break keyword in Erlang section

• Added the Factorials in Erlang section

• Added the Fibonacci sequence in Erlang section

• Added the Modules in Erlang section

• Added the other knowledge of the Erlang programming language section

• Added the Additional comments section

• Added the file info section

• Added the file history section

• No other changes in version 1

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