Erlang Language Programming Tutorials

History

The erlang language was first written in prolog by Joe Armstrong. Ref:audio interview with Joe Armstrong from (http://www.se-radio.net). Joe is a known fan of prolog and borrowed much syntax from prolog in the design of erlang. This first prolog version of erlang was slow and motivated the creation of a virtual machine. Later an emulator called the BEAM was written in C and is about 200,000 lines of C code. It is thought that erlang is short for "Ericsson Language", due to its place of birth.

Overview

Basic Erlang

Get to know the Command Line

Errors - working with exceptions

Processes and Messages

Trapping Exit Signals

Timeouts

Macros

Techniques of Recursion

List Comprehensions

List Comments

Syntax

Functions are defined by the domain of the arguments and the number of arguemnts. A function ends with a period. A function over a particular domain of values is separated by a semicolon. The arrow shows how a particular function of a particular value or variable maps to an output.

fact(0) -> 1;
fact(N) when is_integer(N) -> 
    fact(N-1)*N.

Advanced Syntax

Simple Types

Basic types in erlang include:

atom - alice
integer - 3
float - 3.1415
pid - a process id number <0.42.0>
list - [ things in square brackets ]
tuple - { things in curly braces }

Advanced Types

binary - a binary data block, <<42>>
function - a function, F = fun(X) -> X*X end.
port - a path for data to flow to the outside world
reference - a unique id over all processes
record - the standard erlang data structure

Modules

Adding/Replacing Modules

Erlang is picky about updating or replacing modules of the same name. You should completely remove the old module code from the directory tree, not just rename the containing directory.