Fix bug with recursion in VM

This was introduced in cf7b7db

1 files changed, 8 insertions, 1 deletions

diff --git a/VM.hs b/VM.hs
index e0ed2f4..784c93b 100644
--- a/VM.hs
+++ b/VM.hs
@@ -103,7 +103,14 @@ callClosure info@(Info bbmap gfds _) state@(State { sTempMap = tmap }) cl as =
             Just (GlobFuncDef b _ _) -> do
                 (rv, state') <- vmRunBB info (state { sArgs = map (findRef tmap) as, sCloVals = clvals })
                                         (bbmap Map.! b)
-                return (rv, state' { sArgs = sArgs state, sCloVals = sCloVals state })
+                -- TODO: we restore tempmap here after the call, and that's
+                -- _really_ dodgy. I think it works because we never mutate
+                -- a reference after first assigning it, and without it
+                -- recursion fails, but it feels ugly. A proper solution
+                -- would be to further compile the IR down to something
+                -- that stores its values on a stack, so that recursion is
+                -- handled automatically.
+                return (rv, state' { sArgs = sArgs state, sCloVals = sCloVals state, sTempMap = sTempMap state })
             Nothing ->
                 -- Take 'tail as' to skip the first self-link argument
                 vmRunBuiltin state clname (map (findRef tmap) (tail as))