Erlang (programming language)/Tutorials

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.

Basic Erlang

Get to know the Command Line

Terms

Pattern Matching

Expressions

Functions

Guards

Modules

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.

Popular Modules

math

gb_sets

lists

regexp: Regular Expressions

Nonstandard Modules

Eunit Unit Testing Module

Object Oriented Programming with erlang

Objects with erlang

Functional Programming with erlang

Fun with folding

Iterator

Simplify Numeric Types (auto-demotion of numerical types)

Example programs

Hello World (Serial)

Hello World (parallel)

Prime Sieve with Linda

Autonomous Agents in Erlang -- def: Autonomous Agent.

Advanced OTP

Databases

ETS programming

DETS programming

Mnesia database

Advanced Erlang

Making parsers with yecc

Evaluation

Projects using erlang

• CouchDB - a scalable database for Apache
• Wings3D - a 3-D editor

References

1 - Erlang Man Pages at Erlang,org