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Re: CASE statement [message #27023 is a reply to message #26552]

Mon, 08 October 2001 09:27

John-David T. Smith is currently offline

John-David T. Smith
Messages: 384
Registered: January 2000

Senior Member

Timm Weitkamp wrote:
>
> Paul van Delst <paul.vandelst@noaa.gov> wrote in messagenews:<3BBE2163.F73A162D@noaa.gov>...
>> "Pavel A. Romashkin" wrote:
>>>
>>> Timm Weitkamp wrote:
>>>>
>>>> It actually also has some counterintuitive features. This one, for
>>>> example:
>>>>
>>>> IDL> PRINT, KEYWORD_SET([0])
>>>> 1
>>>
>>> Correct me if I am wrong, but the PURPOSE of KEYWORD_SET is to check if
>>> a KEYWORD is SET. Settable keywords are those that you either set or
>>> don't, either /K_SET or K_SET=0. As such, they should not be set to
>>> arrays. As far as I can see, Keyword_Set is a convenience function. For
>>> value passing keywords, N_elements should be used.
>>> So, it looks to me that the name of this function means exactly what it
>>> is designed for.
>>
>> Excellent point.
>>
>> paulv
>
> Pavel and Paul,
>
> I mostly agree with you. But when you're programming a routine, even
> if you do use KEYWORD_SET in the strictly limited context that it
> should be, it is still possible that the user of the routine
> accidentally passes [0] (or [1]) instead of 0 (or 1) if the keyword is
> passed as an expression and not as an explicit value as in Pavel's
> example. Of course you may then blame the user, but that is of limited
> help.

The paranoid may therefore use:

if n_elements(key) ne 0 then if keyword_set(key[0]) then do_something

or do you contend that key=[1,0] should also be "false"?

JD

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[Message index]

		CASE statement By: K Banerjee on Fri, 07 September 2001 13:17
		Re: CASE statement By: R.Bauer on Wed, 03 October 2001 23:51
		Re: CASE statement By: weitkamp on Fri, 05 October 2001 11:44
		Re: CASE statement By: David Fanning on Wed, 03 October 2001 12:02
		Re: CASE statement By: george.mccabe on Fri, 05 October 2001 09:25
		Re: CASE statement By: David Fanning on Mon, 08 October 2001 09:55
		Re: CASE statement By: John-David T. Smith on Mon, 08 October 2001 09:27
		Re: CASE statement By: R.Bauer on Mon, 08 October 2001 00:19
		Re: CASE statement By: weitkamp on Sat, 06 October 2001 03:01
		Re: CASE statement By: Paul van Delst on Fri, 05 October 2001 14:08
		Re: CASE statement By: Pavel A. Romashkin on Fri, 05 October 2001 12:03

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