Optional parameters: Difference between revisions

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 Named parameters are not builtin, but map-patterns may be used as a substitute. (TODO: Example of this) [[Category:E examples needing attention]]
+=={{header|Ecstasy}}==
+<syntaxhighlight lang="java">
+module OptionalParameters
+    {
+    typedef Type<String  >.Orderer as ColumnOrderer;
+    typedef Type<String[]>.Orderer as RowOrderer;
+    static String[][] sort(String[][]     table,
+                           ColumnOrderer? orderer = Null,
+                           Int            column  = 0,
+                           Boolean        reverse = False,
+                          )
+        {
+        // provide a default orderer
+        orderer ?:= (s1, s2) -> s1 <=> s2;
+        // optionally reverse the order
+        ColumnOrderer byString = reverse
+                ? ((s1, s2) -> orderer(s1, s2).reversed)
+                : orderer;
+        // sort the indicated column
+        RowOrderer byColumn = (row1, row2) -> byString(row1[column], row2[column]);
+        return table.sorted(byColumn);
+        }
+    void run()
+        {
+        String[][] table =
+            [
+            ["c", "x", "i"],
+            ["a", "y", "p"],
+            ["b", "z", "a"],
+            ];
+        show("original input", table);
+        show("by default sort on column 0", sort(table));
+        show("by column 2", sort(table, column=2));
+        show("by column 2 reversed", sort(table, column=2, reverse=True));
+        }
+    void show(String title, String[][] table)
+        {
+        @Inject Console console;
+        console.println($"{title}:");
+        for (val row : table)
+            {
+            console.println($"  {row}");
+            }
+        console.println();
+        }
+    }
+</syntaxhighlight>
+Output:
+<syntaxhighlight>
+original input:
+  [c, x, i]
+  [a, y, p]
+  [b, z, a]
+by default sort on column 0:
+  [a, y, p]
+  [b, z, a]
+  [c, x, i]
+by column 2:
+  [b, z, a]
+  [c, x, i]
+  [a, y, p]
+by column 2 reversed:
+  [a, y, p]
+  [c, x, i]
+  [b, z, a]
+</syntaxhighlight>
 =={{header|Elixir}}==