September 2017 Update

Task/Averages-Pythagorean-means/AppleScript/averages-pythagorean-means-1.applescript

@@ -3,63 +3,66 @@ on arithmetic_mean(xs)
 
     -- sum :: Number -> Number -> Number
     script sum
-        on lambda(accumulator, x)
+        on |λ|(accumulator, x)
             accumulator + x
-        end lambda
+        end |λ|
     end script
 
     foldl(sum, 0, xs) / (length of xs)
 end arithmetic_mean
 
-
 -- geometric_mean :: [Number] -> Number
 on geometric_mean(xs)
 
     -- product :: Number -> Number -> Number
     script product
-        on lambda(accumulator, x)
+        on |λ|(accumulator, x)
             accumulator * x
-        end lambda
+        end |λ|
     end script
 
     foldl(product, 1, xs) ^ (1 / (length of xs))
 end geometric_mean
 
-
 -- harmonic_mean :: [Number] -> Number
 on harmonic_mean(xs)
 
     -- addInverse :: Number -> Number -> Number
     script addInverse
-        on lambda(accumulator, x)
+        on |λ|(accumulator, x)
             accumulator + (1 / x)
-        end lambda
+        end |λ|
     end script
 
     (length of xs) / (foldl(addInverse, 0, xs))
 end harmonic_mean
 
-
--- TEST
+-- TEST -----------------------------------------------------------------------
 on run
-
-    script test
-        on lambda(f)
-            mReturn(f)'s lambda({1, 2, 3, 4, 5, 6, 7, 8, 9, 10})
-        end lambda
-    end script
-
-
-    set {A, G, H} to ¬
-        map(test, {arithmetic_mean, geometric_mean, harmonic_mean})
+    set {A, G, H} to ap({arithmetic_mean, geometric_mean, harmonic_mean}, ¬
+        {{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}})
 
     {values:{arithmetic:A, geometric:G, harmonic:H}, inequalities:¬
         {|A >= G|:A ≥ G}, |G >= H|:G ≥ H}
 end run
 
 
----------------------------------------------------------------------------
--- GENERIC FUNCTIONS
+-- GENERIC FUNCTIONS ----------------------------------------------------------
+
+-- A list of functions applied to a list of arguments
+-- (<*> | ap) :: [(a -> b)] -> [a] -> [b]
+on ap(fs, xs)
+    set {nf, nx} to {length of fs, length of xs}
+    set acc to {}
+    repeat with i from 1 to nf
+        tell mReturn(item i of fs)
+            repeat with j from 1 to nx
+                set end of acc to |λ|(contents of (item j of xs))
+            end repeat
+        end tell
+    end repeat
+    return acc
+end ap
 
 -- foldl :: (a -> b -> a) -> a -> [b] -> a
 on foldl(f, startValue, xs)
@@ -67,7 +70,7 @@ on foldl(f, startValue, xs)
         set v to startValue
         set lng to length of xs
         repeat with i from 1 to lng
-            set v to lambda(v, item i of xs, i, xs)
+            set v to |λ|(v, item i of xs, i, xs)
         end repeat
         return v
     end tell
@@ -79,7 +82,7 @@ on map(f, xs)
         set lng to length of xs
         set lst to {}
         repeat with i from 1 to lng
-            set end of lst to lambda(item i of xs, i, xs)
+            set end of lst to |λ|(item i of xs, i, xs)
         end repeat
         return lst
     end tell
@@ -92,7 +95,7 @@ on mReturn(f)
         f
     else
         script
-            property lambda : f
+            property |λ| : f
         end script
     end if
 end mReturn