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Re: Passing zero as a Parameter/ NOT KEYWORD_SET [message #16067 is a reply to message #16066]

Tue, 29 June 1999 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Martin Schultz (mgs@io.harvard.edu) writes:

>> The best way to proceed is pretend keyword_set() was really
>> named is_defined_and_non_zero(). Forget that it's called
>> keyword_set().

> In fact it is "is_defined_and_uneven" !
> Just try to pass var=2 into a routine and print keyword_set(var). Hope,
> David will take notice of this in his article.

Most people use Keyword_Set for entirely the wrong thing.
Keyword_Set very clearly returns 0 if the argument is 0 or
undefined. It returns a 1 if the argument is *anything*
other than 0 or undefined. It should be used ONLY with
those keywords that require a Boolean value.

But I welcome your comments on the article. (Just don't
bug me night and day until I incorporate your comments. :-)

http://www.dfanning.com/tips/keyword_check.html

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: J.D. Smith on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Vapuser on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: R.Bauer on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Martin Schultz on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Liam Gumley on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: philaldis on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: R.Bauer on Wed, 30 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Pavel Romashkin on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: davidf on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: J.D. Smith on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: J.D. Smith on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: davidf on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Martin Schultz on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: R.Bauer on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: davidf on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: J.D. Smith on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Andy Sowter on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: philaldis on Tue, 29 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Grady Daub on Mon, 28 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: Grady Daub on Mon, 28 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: philaldis on Mon, 28 June 1999 00:00
		Re: Passing zero as a Parameter/ NOT KEYWORD_SET By: luthi on Mon, 28 June 1999 00:00

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