\ 4tH library - ANS CORE - Copyright 2003,2007 J.L. Bezemer
\ You can redistribute this file and/or modify it under
\ the terms of the GNU General Public License

[UNDEFINED] ?DUP [IF]
: 2! SWAP OVER ! CELL+ ! ;
: 2@ DUP CELL+ @ SWAP @ ;
: ?DUP DUP IF DUP THEN ;
[THEN]