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Contents
require 'forwardable'
require 'compo/composite'
module Compo
# Implementation of Composite that stores its children in a Hash.
#
# IDs for items entering a ListComposite may be any permissible hash.
#
# Adding an item at an occupied ID removes the occupant.
class HashComposite
include Composite
extend Forwardable
# Initialises a HashComposite
#
# @api public
# @example Initializes a HashComposite.
# comp = HashComposite.new
def initialize
@children = {}
end
# Returns the HashComposite's children, as a Hash
#
# @api public
# @example Gets the children of an empty HashComposite.
# comp.children
# #=> {}
# @example Gets the children of a populated HashComposite.
# comp.children
# #=> {foo: 3, bar: 5}
#
# @return [Hash] The Hash mapping the IDs of children to their values.
attr_reader :children
private
# Inserts a child into the HashComposite with the given ID
#
# You probably want to use #add instead.
#
# @api private
#
# @param id [Object] The ID under which the child is to be added.
# @param child [Object] The child to add to the HashComposite.
#
# @return [Object] The newly added child.
def add!(id, child)
remove_id(id)
@children[id] = child
end
def_delegator :@children, :delete, :remove_id!
# Creates an ID function for the given child
#
# The returned proc is O(1), as it stores the ID assigned to the child at
# calling time under the assumption that it will not change until removal.
#
# @api private
#
# @param child [Object] The child whose ID is to be returned by the proc.
#
# @return [Proc] A proc returning the child's ID.
def id_function(child)
id = @children.key(child)
proc { id }
end
end
end
Version data entries
9 entries across 9 versions & 1 rubygems