adamantium
Create immutable objects with ease.
This is a small standalone gem featuring a module extracted from axiom. It allows you to make objects immutable in a simple, unobtrusive way.
Examples
require 'adamantium'
require 'securerandom'
class Example
# Inclusion of Adamantium defaults to deep freeze behavior
# of constructor and memoizer
include Adamantium
# Instance and attributes (ivars) are frozen per default
# Example:
#
# object = Example.new
# object.frozen? # => true
# object.attribute.frozen? # => true
#
def initialize
@attribute = "foo bar"
end
attr_reader :attribute
# Memoized method with deeply frozen value (default)
# Example:
#
# object = Example.new
# object.random => ["abcdef"]
# object.random => ["abcdef"]
# object.random.frozen? => true
# object.random[0].frozen? => true
#
def random
[SecureRandom.hex(6)]
end
memoize :random
# Memoized method with non frozen value
# Example:
#
# object = Example.new
# object.buffer # => <StringIO:abcdef>
# object.buffer # => <StringIO:abcdef>
# object.buffer.frozen? # => false
#
def buffer
StringIO.new
end
memoize :buffer, freezer: :noop
# Memoized method with shallow frozen value
# Example:
#
# object = Example.new
# object.random2 => ["abcdef"]
# object.random2 => ["abcdef"]
# object.random2.frozen? => true
# object.random2[0].frozen? => false
#
def random2
[SecureRandom.hex(6)]
end
memoize :random2, freezer: :flat
# Transform method derives changed instances without
# calling the constructor
# Example:
#
# object = Example.new
# object.random => ["abcdef"]
# update = object.edit "baz quux"
# update.random => ["abcdef"]
# update.attribute => "baz quux"
#
def edit(attribute)
transform do
@attribute = attribute
end
end
end
class FlatExample
# Inclusion of Adamantium::Flat defaults to shallow frozen
# behavior for memoizer and constructor
include Adamantium::Flat
# Instance is frozen but attribute is not
# Example:
#
# object = FlatExample.new
# object.frozen? # => true
# object.attribute.frozen? # => false
#
def initialize
@attribute = "foo bar"
end
attr_reader :attribute
# Memoized method with flat frozen value (default with Adamantium::Flat)
# Example:
#
# object = Example.new
# object.random => ["abcdef"]
# object.random => ["abcdef"]
# object.random.frozen? => true
# object.random[0].frozen? => false
#
def random
[SecureRandom.hex(6)]
end
memoize :random
end
Credits
Contributing
See CONTRIBUTING.md for details.
Copyright
Copyright © 2012-2014 Dan Kubb. See LICENSE for details.