Call By Reference
- To: mathgroup at smc.vnet.net
- Subject: [mg6774] Call By Reference
- From: Adalbert Hanssen <hsse at amath01.amath.zeiss.de>
- Date: Fri, 18 Apr 1997 02:37:41 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Dear Ebersloh, your problem can easily be solved using Hold, HoldFirst etc. Define your function fun as usually, then e.g. SetAtributes[fun, HoldFirst], and the invoke fun. Of course, then you must supply a symbol for held parameters. The following does *NOT* work for a function unsing Hold or any of its flavours (as the counterpart also does not for call-by-reference parameters in other programming languages): f[x_]:=... SetAttributes[f,HoldFirst]; f[1] (* this does not work, only supply *symbols* *) x=1; f[x] (* this works *) best regards Dipl-Math. Adalbert Hanszen <hsse at amath01.amath.zeiss.de>