--- a/test.yl	Tue Sep 03 20:20:06 2019 +0200
+++ b/test.yl	Mon Sep 09 19:52:37 2019 +0200
@@ -13,12 +13,29 @@
 ")
 
 (defn pow (a b)
- (let next (- b 1))
  (if (== b 0) 1
   ((* a (pow a (- b 1))))
   )
  )
 
+(defn sum-to (n)
+ (if (== n 0) 0 ((+ n (sum-to (- n 1))))))
+
 -- Here we output it
 (print (fac 13) newline)
 (print (pow 2 10) newline)
+(print (sum-to 100) newline)
+
+-- This produces a "generator function", yielding numbers from 0 to n.
+-- This only works once, however, as `counter` is statically allocated.
+-- TODO: Implement built-in to dynamically create references.
+(defn make-gen (n)
+ (let counter 0)
+ (let max n) -- we can't reference the argument in a closure :\
+ (defn increment () (if (== counter max) ((undef)) ((let counter (+ counter 1)) counter)))
+ increment)
+
+(let my-gen (make-gen 10))
+(let my-gen2 (make-gen 10))
+(print (my-gen) (my-gen) (my-gen) (my-gen2))
+(print newline)