Association

General binary association allows one object to be associated with another. It has a variety of uses, link-lists, simple ordered maps and mixed collections, among them.

Usage

Associations can be used to draw simple relationships.

  :Apple >> :Fruit
  :Apple >> :Red

  :Apple.associations #=> [ :Fruit, :Red ]

It can also be used for simple lists of ordered pairs.

  c = [ :a >> 1, :b >> 2 ]
  c.each { |k,v| puts "#{k} associated with #{v} }

produces

  a associated with 1
  b associated with 2

Limitations

The method :>> is used to construct the association. It is a rarely used method so it is generally available. But you can‘t use an Association while extending any of the following classes becuase they use #>> for other things.

  Bignum
  Fixnum
  Date
  IPAddr
  Process::Status

Methods

<=>
[]
inspect
invert!
new
to_ary
to_s

Included Modules

Comparable

Classes and Modules

Module Association::Kernel

Constants

REFERENCE	=	Hash.new{ \|h,k,v\| h[k]=[] }
	Store association references.

Attributes

[RW]	index
[RW]	value

Public Class methods

[](*args)

[ show source ]

# File lib/facets/association.rb, line 105
  def self.[](*args)
    new(*args)
  end

new(index, value=nil)

[ show source ]

# File lib/facets/association.rb, line 109
  def initialize(index, value=nil)
    @index = index
    @value = value
  end

Public Instance methods

<=>(assoc)

[ show source ]

# File lib/facets/association.rb, line 114
  def <=>(assoc)
    return -1 if self.value < assoc.value
    return  1 if self.value > assoc.value
    return  0 if self.value == assoc.value
  end

inspect()

[ show source ]

# File lib/facets/association.rb, line 130
  def inspect
    %{#{@index.inspect} >> #{@value.inspect}}
  end

invert!()

[ show source ]

# File lib/facets/association.rb, line 120
  def invert!
    temp = @index
    @index = @value
    @value = temp
  end

to_ary()

[ show source ]

# File lib/facets/association.rb, line 134
  def to_ary
    [ @index, @value ]
  end

to_s()

[ show source ]

# File lib/facets/association.rb, line 126
  def to_s
    return "#{index.to_s}#{value.to_s}"
  end