Add [DEFINED] and [UNDEFINED] (#127)

[debian/pforth] / fth / condcomp.fth

diff --git a/fth/condcomp.fth b/fth/condcomp.fth
index dc65c6bc76616d1c0da991e9d59a15234645dfbd..762cde89a605ffe45ef1f2d3ff2fab43be96674b 100644 (file)
--- a/fth/condcomp.fth
+++ b/fth/condcomp.fth
@@ -46,5 +46,15 @@ anew task-condcomp.fth
 
 : EXISTS? ( <name> -- flag , true if defined )
     bl word find
-    swap drop
+    nip 0<>
+; immediate
+
+: [DEFINED] ( <name> -- flag , true if defined, ANS )
+    bl word find
+    nip 0<>
+; immediate
+
+: [UNDEFINED] ( <name> -- flag , true if not defined, ANS )
+    bl word find
+    nip 0=
 ; immediate