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Re: Bug in N_PARAMS? [message #64048 is a reply to message #64011]

Mon, 01 December 2008 06:11

Jeremy Bailin
Messages: 618
Registered: April 2008

Senior Member

On Nov 30, 5:06 pm, Mark <mark.h...@gmail.com> wrote:
> On Nov 28, 11:02 pm, Reimar Bauer <R.Ba...@fz-juelich.de> wrote:
>
>> The usecase for me is to call a helper routine if not enough parameters
>> were used.
>
>> e.g.
>
>> if n_params() lt 2 then begin
>> MESSAGE,call_help(),/cont
>> return
>> endif
>
> Sure, but even if 2 parameters were supplied, you still don't know if
> the variables they're associated with are defined. If you're going to
> check for that anyway, with N_ELEMENTS, the N_PARAMS check is
> redundant.
>
> Eg.
>
> pro mypro, a, b
>
> if n_elements(a) eq 0 || n_elements(b) eq 0 then begin
> MESSAGE,call_help(),/cont
> return
> endif
>
> end

Except that there are valid reasons for passing in an undefined
variable, if it's used for output. So it's perfectly legitimate to
want to know whether it was passed in without caring whether it is
defined.

-Jeremy.

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[Message index]

		Bug in N_PARAMS? By: Kenneth P. Bowman on Mon, 24 November 2008 11:31
		Re: Bug in N_PARAMS? By: David Fanning on Tue, 02 December 2008 07:10
		Re: Bug in N_PARAMS? By: Mark[1] on Mon, 01 December 2008 14:55
		Re: Bug in N_PARAMS? By: Jeremy Bailin on Mon, 01 December 2008 06:11
		Re: Bug in N_PARAMS? By: Mark[1] on Sun, 30 November 2008 14:06
		Re: Bug in N_PARAMS? By: R.Bauer on Fri, 28 November 2008 02:02
		Re: Bug in N_PARAMS? By: pgrigis on Wed, 03 December 2008 11:15
		Re: Bug in N_PARAMS? By: David Fanning on Wed, 03 December 2008 10:49
		Re: Bug in N_PARAMS? By: R.Bauer on Wed, 03 December 2008 09:59

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