September Morn Update

Task/Reverse-a-string/Visual-Basic-.NET/reverse-a-string.visual

@@ -1,5 +1,57 @@
-  Function Reverse(ByVal s As String) As String
-    Dim t() as Char = s.toCharArray
-    Array.reverse(t)
-    Return new String(t)
-  End Function
+#Const REDIRECTOUT = True
+
+Module Program
+    Const OUTPATH = "out.txt"
+
+    ReadOnly TestCases As String() = {"asdf", "as⃝df̅", "Les Misérables"}
+
+    ' SIMPLE VERSION
+    Function Reverse(s As String) As String
+        Dim t = s.ToCharArray()
+        Array.Reverse(t)
+        Return New String(t)
+    End Function
+
+    ' EXTRA CREDIT VERSION
+    Function ReverseElements(s As String) As String
+        ' In .NET, a text element is series of code units that is displayed as one character, and so reversing the text
+        ' elements of the string correctly handles combining character sequences and surrogate pairs.
+        Dim elements = Globalization.StringInfo.GetTextElementEnumerator(s)
+        Return String.Concat(AsEnumerable(elements).OfType(Of String).Reverse())
+    End Function
+
+    ' Wraps an IEnumerator, allowing it to be used as an IEnumerable.
+    Iterator Function AsEnumerable(enumerator As IEnumerator) As IEnumerable
+        Do While enumerator.MoveNext()
+            Yield enumerator.Current
+        Loop
+    End Function
+
+    Sub Main()
+        Const INDENT = "    "
+
+#If REDIRECTOUT Then
+        Const OUTPATH = "out.txt"
+        Using s = IO.File.Open(OUTPATH, IO.FileMode.Create),
+              sw As New IO.StreamWriter(s)
+            Console.SetOut(sw)
+#Else
+        Try
+            Console.OutputEncoding = Text.Encoding.ASCII
+            Console.OutputEncoding = Text.Encoding.UTF8
+            Console.OutputEncoding = Text.Encoding.Unicode
+        Catch ex As Exception
+            Console.WriteLine("Failed to set console encoding to Unicode." & vbLf)
+        End Try
+#End If
+            For Each c In TestCases
+                Console.WriteLine(c)
+                Console.WriteLine(INDENT & "SIMPLE:   " & Reverse(c))
+                Console.WriteLine(INDENT & "ELEMENTS: " & ReverseElements(c))
+                Console.WriteLine()
+            Next
+#If REDIRECTOUT Then
+        End Using
+#End If
+    End Sub
+End Module