From: sforman <sforman@hushmail.com>
Date: Sat, 29 Jul 2023 16:55:28 +0000 (-0700)
Subject: pop
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=c50f2a75412d2533ca21332f4870ddf96d48f08c;p=joypy%2FThun.git

pop
---

diff --git a/implementations/Elm/src/Joy.elm b/implementations/Elm/src/Joy.elm
index 67d90c3..42c3e52 100644
--- a/implementations/Elm/src/Joy.elm
+++ b/implementations/Elm/src/Joy.elm
@@ -47,6 +47,7 @@ joy_eval symbol stack expression =
         "cons" -> joy_cons stack expression
         "dup" -> joy_dup stack expression
         "first" -> joy_first stack expression
+        "pop" -> joy_pop stack expression
         "rest" -> joy_rest stack expression
         _ -> Err ("Unknown word: " ++ symbol)
 
@@ -100,6 +101,13 @@ joy_first stack expression =
         Err msg -> Err msg
 
 
+joy_pop : JList -> JList -> Result String (JList, JList)
+joy_pop stack expression =
+    case pop_any(stack) of
+        Ok (_, s0) -> Ok (s0, expression)
+        Err msg -> Err msg
+
+
 joy_rest : JList -> JList -> Result String (JList, JList)
 joy_rest stack expression =
     case pop_list(stack) of