all tasks

Task/Sort-stability/REBOL/sort-stability.rebol

@@ -0,0 +1,18 @@
+; REBOL's sort function is not stable by default. You need to use a custom comparator to make it so.
+
+blk: [
+    [UK London]
+    [US New-York]
+    [US Birmingham]
+    [UK Birmingham]
+]
+sort/compare blk func [a b] [either a/2 < b/2 [-1] [either a/2 > b/2 [1] [0]]]
+
+; Note that you can also do a stable sort without nested blocks.
+blk: [
+    UK London
+    US New-York
+    US Birmingham
+    UK Birmingham
+]
+sort/skip/compare blk 2 func [a b] [either a < b [-1] [either a > b [1] [0]]]