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Re: problem with symbol and function declaration

• To: mathgroup at smc.vnet.net
• Subject: [mg30225] Re: problem with symbol and function declaration
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Fri, 3 Aug 2001 00:55:57 -0400 (EDT)
• Organization: Universitaet Leipzig
• References: <9kavlj$c2q$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

a) *don't* use such kind of definitions ! over bars, subscripts ..
   and friends are for Input/Output formating *not* for programming !   
b)

OverBar[x] = 2;

test[xx_, sym_:x] = 2*OverBar[sym]*x /. x -> xx;
test[1]

work as expected. Your definition can't work because

test[x_] = 2*OverBar[x]*x

will never know that the pattern x_ should use first
the symbol x and than replace the symbol x by the value
of the pattern x_.

Regards
  Jens


Martin Richter wrote:
> 
> Hi
> 
> OverBar[x]=2;
> test[x_] = 2*OverBar[x]*x;
> test[1]
> 
> gives
>  _
> 21
> 
> and not 4. So it is like Mathematica is looking at OverBar[x] as two symbols
> and not one ?
> Maybe it is a silly idea so use non ASCII letters for variables.
> 
> Thanks for any comments
> Martin
> 
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