Add l (length) instruction

2 files changed, 4 insertions, 0 deletions

diff --git a/rip-lang.txt b/rip-lang.txt
index 75ed5bf..f5f2146 100644
--- a/rip-lang.txt
+++ b/rip-lang.txt
@@ -11,6 +11,7 @@ i: increment
 d: decrement
 r: pops the number of items to rotate clockwise
 R: pops the number of items to rotate anti-clockwise
+l: push length of stack (before this push)
 a s m q: + - * / (add, subtract, multiply, quotient (integer))
 G L E: greater, less, equal; booleans are 1 and 0, as you expect
 n: not; equivalent to 0E
diff --git a/rip.hs b/rip.hs
index ca8675f..14e7f6f 100644
--- a/rip.hs
+++ b/rip.hs
@@ -150,6 +150,9 @@ rip' code@(x:xs) fns st = do
                     (begin, rest) = (take n newst, drop n newst)
                     res = last begin : init begin ++ rest  --SLOW!
 
+        'l' ->
+            rip' xs fns (fromIntegral (length st) : st)
+
         'a' ->
             rip' xs fns (a + b : cs)
                 where (b:a:cs) = st