Re: Length of actual parameters in a function call.

*To*: mathgroup at smc.vnet.net*Subject*: [mg47124] Re: Length of actual parameters in a function call.*From*: Paul Abbott <paul at physics.uwa.edu.au>*Date*: Fri, 26 Mar 2004 03:56:33 -0500 (EST)*Organization*: The University of Western Australia*References*: <c3udpe$9om$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <c3udpe$9om$1 at smc.vnet.net>, "E. Martin-Serrano" <eMartinSerrano at houston.rr.com> wrote: > A few weeks ago, reviewing some tutorials on pattern matching and error > handling, I came across an undocumented function to monitor the number of > parameters submitted to a function in a call; but somehow I lost its track > later. I guess that it must be something well-known by our specialists. Any > help about where to locate it? > > The undocumented feature helps in tracking situations as when we define > "MyFunction[a_,b_,c_]:= something" and then it is called as "myFunction[a]" > leaving the function unevaluated. MyFunction[a_, b_, c_] := something MyFunction[args___] := Null /; Length[{args}] != 3 && Message[MyFunction::argx, MyFunction, Length[{args}]] MyFunction[a] Cheers, Paul -- Paul Abbott Phone: +61 8 9380 2734 School of Physics, M013 Fax: +61 8 9380 1014 The University of Western Australia (CRICOS Provider No 00126G) 35 Stirling Highway Crawley WA 6009 mailto:paul at physics.uwa.edu.au AUSTRALIA http://physics.uwa.edu.au/~paul

**Follow-Ups**:**Re: Re: Length of actual parameters in a function call.***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>