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Re: Unknown options in Mma 3.0: built-in functions vs. user-defined functions

• To: mathgroup at smc.vnet.net
• Subject: [mg6988] Re: [mg6943] Unknown options in Mma 3.0: built-in functions vs. user-defined functions
• From: David Withoff <withoff>
• Date: Thu, 1 May 1997 14:48:36 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

> Does anyone know why the response to the attempted use of a function
> with an unknown option differs depending on whether the function is
> built in or user-defined?
> 
> If I try to use, say, Plot, with an unknown option (call it "newopt"),
> I get the error message Plot::optx: Unknown option newopt in
> Plot[.....].  However, if I use a user-defined function with an
> unknown option, I get no error message -- rather, the option is simply
> ignored.
> 
> Bob Lawrence

This is a reflection of coding conventions and programmer choices
rather than a distinction between built-in functions and user-defined
functions.  The people who write built-in functions (the programmers
at Wolfram Research) tend to include tests for unknown options in
built-in functions.  The same tests can be (and often are) included
in user-defined functions too, but not all programmers do that.

Dave Withoff
Wolfram Research