Data update

Task/Polymorphic-copy/Julia/polymorphic-copy.jl

@@ -0,0 +1,38 @@
+abstract type Jewel end
+
+mutable struct RoseQuartz <: Jewel
+    carats::Float64
+    quality::String
+end
+
+mutable struct Sapphire <: Jewel
+    color::String
+    carats::Float64
+    quality::String
+end
+
+color(j::RoseQuartz) = "rosepink"
+color(j::Jewel) = "Use the loupe."
+color(j::Sapphire) = j.color
+
+function testtypecopy()
+    a = Sapphire("blue", 5.0, "good")
+    b = RoseQuartz(3.5, "excellent")
+
+    j::Jewel = deepcopy(b)
+
+    println("a is a Jewel? ", a isa Jewel)
+    println("b is a Jewel? ", a isa Jewel)
+    println("j is a Jewel? ", a isa Jewel)
+    println("a is a Sapphire? ", a isa Sapphire)
+    println("a is a RoseQuartz? ", a isa RoseQuartz)
+    println("b is a Sapphire? ", b isa Sapphire)
+    println("b is a RoseQuartz? ", b isa RoseQuartz)
+    println("j is a Sapphire? ", j isa Sapphire)
+    println("j is a RoseQuartz? ", j isa RoseQuartz)
+
+    println("The color of j is ", color(j), ".")
+    println("j is the same as b? ", j == b)
+end
+
+testtypecopy()