Data commit

Task/Optional-parameters/F-Sharp/optional-parameters.fs

@@ -0,0 +1,37 @@
+type Table(rows:string[][]) =
+   // in-place sorting of rows
+   member x.Sort(?ordering, ?column, ?reverse) =
+      let ordering = defaultArg ordering compare
+      let column   = defaultArg column   0
+      let reverse  = defaultArg reverse  false
+
+      let factor = if reverse then -1 else 1
+      let comparer (row1:string[]) (row2:string[]) =
+         factor * ordering row1.[column] row2.[column]
+
+      Array.sortInPlaceWith comparer rows
+
+   member x.Print() =
+      for row in rows do printfn "%A" row
+
+// Example usage
+let t = new Table([| [|"a";   "b"; "c"|]
+                     [|"";    "q"; "z"|]
+                     [|"can"; "z"; "a"|] |])
+
+printfn "Unsorted"; t.Print()
+
+t.Sort()
+printfn "Default sort"; t.Print()
+
+t.Sort(column=2)
+printfn "Sorted by col. 2"; t.Print()
+
+t.Sort(column=1)
+printfn "Sorted by col. 1"; t.Print()
+
+t.Sort(column=1, reverse=true)
+printfn "Reverse sorted by col. 1"; t.Print()
+
+t.Sort(ordering=fun s1 s2 -> compare s2.Length s1.Length)
+printfn "Sorted by decreasing length"; t.Print()