enum

class Enum < Object

An Enum is a type-safe data type, similar to enum in C/C++. When an Enum element is printed, the name of the Enum is printed instead of the value (unlike in C/C++, where Enums are just special integers). An Enum element only compares equal to another item if the other item is an Enum element and has the same value.

Eg.:

  E = Enum[:B, :C, :D]
  F = Enum.new(:A, :B, :C, 10, :D)
  p E::C.type       #=> EnumTest::E
  p E::C.to_s       #=> C
  p E::C.to_i       #=> 1
  p F::D.type       #=> EnumTest::F
  p F::D.to_s       #=> D
  p F::D.to_i       #=> 10

class Element < Object

An Enum::Element is more type-safe than a Fixnum. Additionally, we can have other Element types derive from this one.

Mixins

Comparable
Enumerable

Public Methods

initialize(name, value)

Create a new Enum::Element; only used internally.

to_i()

Retrieve the value of this element (which is usually an integer).

Returns: the value of this element.

to_s()

Convert this element to a string.

Returns: a string containing the name of this element.

value

value is an alias for to_i.

name

name is an alias for to_s.

<=>(other)

Compare this element to another element.

Returns: 0 if both elements are the same type and have the same type, -1 if this element is determined to be less than the other element, or 1 if this element is determined to be greater than the other element.

self.each(&block)

Iterate through all the Enum Elements in a customer in order.

Returns: the last value from the last call to yield.

self.lookup_table()

Checks to see whether a lookup table has been created yet, creates it if it hasn't been, and returns the lookup table. The lookup table matches a value (usually Fixnum) to an Enum Element.

Returns: a lookup table for this Enum type.

Public Methods

self.[](*args)

A synonym for Enum.new

self.new(*args)

Create a new Enum type

args	a list of arguments representing the possible values for this Enum type

Returns: a new class (a customer, see below) that derives from Enum::Element representing the new Enum type.

class customer < Element

Public Methods

customer.new(enum)

Construct an Enum Element from a Fixnum (or whatever value type we are using) or a name or a string (or anything else that has a to_s function that generates a valid constant).

Returns: a new Enum Element.