2016 Update

Task/Y-combinator/AppleScript/y-combinator-1.applescript

@@ -0,0 +1,99 @@
+-- Y COMBINATOR
+
+on |Y|(f)
+    script
+        on lambda(y)
+            script
+                on lambda(arg)
+                    y's lambda(y)'s lambda(arg)
+                end lambda
+            end script
+
+            f's lambda(result)
+
+        end lambda
+    end script
+
+    result's lambda(result)
+end |Y|
+
+
+-- TEST
+on run
+
+    -- Factorial
+    script fact
+        on lambda(f)
+            script
+                on lambda(n)
+                    if n = 0 then return 1
+                    n * (f's lambda(n - 1))
+                end lambda
+            end script
+        end lambda
+    end script
+
+
+    -- Fibonacci
+    script fib
+        on lambda(f)
+            script
+                on lambda(n)
+                    if n = 0 then return 0
+                    if n = 1 then return 1
+                    (f's lambda(n - 2)) + (f's lambda(n - 1))
+                end lambda
+            end script
+        end lambda
+    end script
+
+    {facts:map(|Y|(fact), range(0, 11)), fibs:map(|Y|(fib), range(0, 20))}
+
+    --> {facts:{1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800},
+    --> fibs:{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765}}
+
+end run
+
+
+---------------------------------------------------------------------------
+
+
+-- GENERIC FUNCTIONS (FOR TEST)
+
+-- 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 lambda(item i of xs, i, xs)
+        end repeat
+        return lst
+    end tell
+end map
+
+-- range :: Int -> Int -> [Int]
+on range(m, n)
+    if n < m then
+        set d to -1
+    else
+        set d to 1
+    end if
+    set lst to {}
+    repeat with i from m to n by d
+        set end of lst to i
+    end repeat
+    return lst
+end range
+
+-- Lift 2nd class handler function into 1st class script wrapper
+-- mReturn :: Handler -> Script
+on mReturn(f)
+    if class of f is script then
+        f
+    else
+        script
+            property lambda : f
+        end script
+    end if
+end mReturn