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Re: Length of actual parameters in a function call.

• To: mathgroup at smc.vnet.net
• Subject: [mg47498] Re: Length of actual parameters in a function call.
• From: Torben Winther Graversen <immtwg at bohr.gbar.dtu.dk>
• Date: Wed, 14 Apr 2004 07:16:56 -0400 (EDT)
• Organization: UNI-C
• References: <c3udpe$9om$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

E. Martin-Serrano <eMartinSerrano at houston.rr.com> wrote:
: Hi,

: 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.


Hi,

Perhaps the one you are looking for is ArgumentCountQ ?

I stumbled on it a few days ago on Ted Ersek's Tricks page:

http://www.verbeia.com/mathematica/tips/HTMLLinks/Tricks_210.html

The documentation on Wolfram's site is at:

http://support.wolfram.com/mathematica/kernel/Symbols/System/ArgumentCountQ.html

ArgumentCountQ[head,len,min,max] tests whether the number len of 
arguments of a function head is between min and max. 



Regards,

  Torben