Data commit

Task/Deepcopy/Ruby/deepcopy.rb

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+# _orig_ is a Hash that contains an Array.
+orig = { :num => 1, :ary => [2, 3] }
+orig[:cycle] = orig	# _orig_ also contains itself.
+
+# _copy_ becomes a deep copy of _orig_.
+copy = Marshal.load(Marshal.dump orig)
+
+# These changes to _orig_ never affect _copy_,
+# because _orig_ and _copy_ are disjoint structures.
+orig[:ary] << 4
+orig[:rng] = (5..6)
+
+# Because of deep copy, orig[:ary] and copy[:ary]
+# refer to different Arrays.
+p orig	# => {:num=>1, :ary=>[2, 3, 4], :cycle=>{...}, :rng=>5..6}
+p copy	# => {:num=>1, :ary=>[2, 3], :cycle=>{...}}
+
+# The original contains itself, and the copy contains itself,
+# but the original and the copy are not the same object.
+p [(orig.equal? orig[:cycle]),
+   (copy.equal? copy[:cycle]),
+   (not orig.equal? copy)]	# => [true, true, true]