Module: Cloneable

Defined in:
lib/standard/facets/cloneable.rb

Overview

Clonable provides a standard basis for adding deep cloneablity to a class via the standard #dup and #clone methods.

Cloneable was originally ported from Jim Weirich’s Rake. The current version is the work of Ken Bloom.

DEPRECATED: A better approach is to provide a #deep_dup and and a #deep_clone, then if a class needs these for #dup and #clone they can just alias them.

CREDIT: Ken Bloom

Instance Method Summary collapse

Instance Method Details

#initialize_copy(sibling) ⇒ Object 



14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
# File 'lib/standard/facets/cloneable.rb', line 14

def initialize_copy(sibling)
  # First duplicate my superclass' state. Note that if it's duplicating
  # instance variables, this will be overwritten, but this is important
  # because we could be dealing with a C extension with state hidden from
  # the Ruby interpreter.
  super

  # We want to know if we're being dup'ed or clone'd, because we want to
  # preserve the state of our internals the same way our state is being
  # preserved. (If we can't figure it out, we'll just use #dup.)
  operation = (
    copy_call  = caller.find{|x| x !~ /'initialize_copy'/}
    copy_match = copy_call.match(/`(dup|clone)'/)
    copy_match ? copy_match[1] : :dup
  )

  sibling.instance_variables.each do |ivar|
    value = sibling.instance_variable_get(ivar)

    # Set my instance variable to be a #dup or #clone
    # or my sibling, depending on what's happening to me right now.
    instance_variable_set(ivar, value.send(operation))
  end
end