September Morn Update

Task/Permutations/AppleScript/permutations-1.applescript

@@ -2,23 +2,27 @@
 
 -- permutations :: [a] -> [[a]]
 on permutations(xs)
-    script firstElement
-        on |λ|(x)
-            script tailElements
-                on |λ|(ys)
-                    {{x} & ys}
+    script go
+        on |λ|(xs)
+            script h
+                on |λ|(x)
+                    script ts
+                        on |λ|(ys)
+                            {{x} & ys}
+                        end |λ|
+                    end script
+                    concatMap(ts, go's |λ|(|delete|(x, xs)))
                 end |λ|
             end script
 
-            concatMap(tailElements, permutations(|delete|(x, xs)))
+            if {} ≠ xs then
+                concatMap(h, xs)
+            else
+                {{}}
+            end if
         end |λ|
     end script
-
-    if length of xs > 0 then
-        concatMap(firstElement, xs)
-    else
-        {{}}
-    end if
+    go's |λ|(xs)
 end permutations
 
 
@@ -58,17 +62,6 @@ on |delete|(x, xs)
     end if
 end |delete|
 
--- map :: (a -> b) -> [a] -> [b]
-on map(f, xs)
-    tell mReturn(f)
-        set lng to length of xs
-        set lst to {}
-        repeat with i from 1 to lng
-            set end of lst to |λ|(item i of xs, i, xs)
-        end repeat
-        return lst
-    end tell
-end map
 
 -- Lift 2nd class handler function into 1st class script wrapper
 -- mReturn :: Handler -> Script