Aldwin Vlasblom Avaq

Algebraic Law Cheatsheet

An overview of algebraic laws from the perspective of a functional programmer. I've used a Haskell-esque syntax for the definitions of the laws and examples.

General Laws

name	definition	example
Identity [¹][]	`f x = x`	`add 0 42 = 42`

	-- Create our directories table.
	CREATE TABLE `directories` (
	`id` int(11) NOT NULL AUTO_INCREMENT,
	`name` varchar(255) DEFAULT NULL,
	`lft` int(11) NOT NULL,
	`rgt` int(11) NOT NULL,
	PRIMARY KEY (`id`),
	UNIQUE KEY `directory_lft` (`lft`),
	UNIQUE KEY `directory_rgt` (`rgt`)
	) ENGINE=InnoDB DEFAULT CHARSET=utf8;