From d42b0088f674ffdcd607016213c66455864b7588 Mon Sep 17 00:00:00 2001
From: Tim Vaughan <tgvaughan@gmail.com>
Date: Fri, 22 Jul 2016 20:24:41 +1200
Subject: [PATCH] Added tail-call optimization.

---
 defer-is.4th | 2 ++
 scheme.4th   | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/defer-is.4th b/defer-is.4th
index 1b171b6..3949d0c 100644
--- a/defer-is.4th
+++ b/defer-is.4th
@@ -40,3 +40,5 @@ hide abort-defer
 : goto ( cfa -- )
     R> drop execute ;
 
+: goto-prime ( cfa -- )
+    R> R> 2drop execute ;
diff --git a/scheme.4th b/scheme.4th
index cecacff..893b20b 100644
--- a/scheme.4th
+++ b/scheme.4th
@@ -981,7 +981,8 @@ defer eval
                 2drop ( env body )
                 car 2swap ( exp env )
 
-                eval \ TODO: tail call optimization
+                ['] eval goto-prime  \ Tail call optimization
+                \ eval               \ No tail call optimization
             endof
 
             bold fg red ." Object not applicable. Aboring." reset-term cr
-- 
2.20.1