Data commit

Task/Comma-quibbling/REBOL/comma-quibbling-1.rebol

@@ -0,0 +1,18 @@
+Rebol []
+
+comma-quibbling: func [block] [
+    rejoin [
+        "^{"
+
+        to-string use [s] [
+            s: copy block
+            s: next s
+            forskip s 2 [insert s either tail? next s [" and "] [", "]]
+            s: head s
+        ]
+
+        "^}"
+    ]
+]
+
+foreach t [[] [ABC] [ABC DEF] [ABC DEF G H]] [print comma-quibbling t]

Task/Comma-quibbling/REBOL/comma-quibbling-2.rebol

@@ -0,0 +1,24 @@
+Rebol []
+
+; builds string instead of using an intermediate block
+
+comma-quibbling: func [block /oxford /local s length] [
+    length: length? block
+    rejoin [
+        "^{"
+
+        either length < 2 [to-string block] [
+            s: to-string block/1
+            for n 2 (length - 1) 1 [repend s [", " pick block n]]
+            if all [oxford (length > 2)] [append s ","]
+            repend s [" and " last block]
+        ]
+
+        "^}"
+    ]
+]
+
+test: [[] [ABC] [ABC DEF] [ABC DEF G H]]
+foreach t test [print comma-quibbling t]
+print "Now with Oxford comma"
+foreach t test [print comma-quibbling/oxford t]