From 143b71102822bc70b0d559a57306e456ff5055d5 Mon Sep 17 00:00:00 2001
From: Simon Forman <sforman@hushmail.com>
Date: Mon, 12 Aug 2019 21:08:35 -0700
Subject: [PATCH] swapd function

---
 thun/gnu-prolog/thun.pl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/thun/gnu-prolog/thun.pl b/thun/gnu-prolog/thun.pl
index b3651b6..3dcb8a9 100644
--- a/thun/gnu-prolog/thun.pl
+++ b/thun/gnu-prolog/thun.pl
@@ -94,6 +94,7 @@ func(unit,      [X|S], [[X]|S]).
 func(thunk,        S ,   [X|S]).
 
 func(rolldown, [A, B, C|S], [B, C, A|S]).
+func(swapd,    [A, B, C|S], [A, C, B|S]).
 func(dupd,        [A, B|S], [A, B, B|S]).
 func(over,        [A, B|S], [B, A, B|S]).
 func(tuck,        [A, B|S], [A, B, A|S]).