June 2018 Update

Task/List-comprehensions/AppleScript/list-comprehensions-1.applescript

@@ -51,24 +51,19 @@ end run
 
 -- (>>=) :: Monad m => m a -> (a -> m b) -> m b
 on |>>=|(xs, f)
-    concat(map(f, xs))
+    concatMap(f, xs)
 end |>>=|
 
--- concat :: [[a]] -> [a] | [String] -> String
-on concat(xs)
-    script append
-        on |λ|(a, b)
-            a & b
-        end |λ|
-    end script
-
-    if length of xs > 0 and class of (item 1 of xs) is string then
-        set empty to ""
-    else
-        set empty to {}
-    end if
-    foldl(append, empty, xs)
-end concat
+-- concatMap :: (a -> [b]) -> [a] -> [b]
+on concatMap(f, xs)
+    set acc to {}
+    tell mReturn(f)
+        repeat with x in xs
+            set acc to acc & |λ|(contents of x)
+        end repeat
+    end tell
+    return acc
+end concatMap
 
 -- enumFromTo :: Int -> Int -> [Int]
 on enumFromTo(m, n)
@@ -84,30 +79,6 @@ on enumFromTo(m, n)
     return lst
 end enumFromTo
 
--- foldl :: (a -> b -> a) -> a -> [b] -> a
-on foldl(f, startValue, xs)
-    tell mReturn(f)
-        set v to startValue
-        set lng to length of xs
-        repeat with i from 1 to lng
-            set v to |λ|(v, item i of xs, i, xs)
-        end repeat
-        return v
-    end tell
-end foldl
-
--- 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
 on mReturn(f)