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Re: Bug in N_PARAMS? [message #64066 is a reply to message #64011]

Fri, 28 November 2008 02:02

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

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

The user get's shown the CALLING SEQUENCE description

cheers
Reimar

Mark schrieb:
> On Nov 26, 3:29 am, "Kenneth P. Bowman" <k-bow...@null.edu> wrote:
>> Ah. That significantly restricts the utility of
>>
>> SWITCH N_PARAMS() OF
>> 0 : ...
>>
>> ENDSWITCH
>>
>> to provide default values for optional parameters.
>
> Indeed. N_ELEMENTS is what you need for that. The only use I have
> found for N_PARAMS is for writing wrapper routines
>
> pro wrapper, P1, P2, P3, P4, _REF_EXTRA=_extra
> ;; Do some other stuff
> case n_params() of
> 0: wrappee, _STRICT_EXTRA=_extra
> 1: wrappee, P1, _STRICT_EXTRA=_extra
> 2: wrappee, P1, P2, _STRICT_EXTRA=_extra
> 3: wrappee, P1, P2, P3, _STRICT_EXTRA=_extra
> 4: wrappee, P1, P2, P3, P4, _STRICT_EXTRA=_extra
> endcase
> end
>
> Ugly, but sometimes necessary.

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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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