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Re: variables in common blocks [message #53866 is a reply to message #53865]

Fri, 04 May 2007 08:56

lasse
Messages: 48
Registered: February 2007

Member

On 4 May, 16:16, David Fanning <n...@dfanning.com> wrote:
> Lasse Clausen writes:
>> Ok. I'll describe what I am using common blocks for: Whatever day
>> during the week, I am doing one of the following:
>> 1) read data
>> 2) process data
>> 3) plot data
>> Since there are many different ways to process or plot data, it is
>> nice to read the data into common blocks, so that when I decide to
>> process or plot the data differently, I do not have to read it in
>> again.
>
>> If you have an easy solution on how to avoid common blocks, shoot. And
>> why are common blocks bad? Is it the same reason "goto" statements are
>> bad?
>
> Oh, oh. *I* didn't want to get into it. I just wanted
> to light the fire. :-(
>
> OK, there is *nothing* inherently evil about either Common
> blocks or GOTO statements. Both have a purpose, and I have
> used both (I think, although I can't remember a specific
> instance of either).
>
> But what generally makes both Common blocks and GOTO
> statements pernicious is how easy it is for inexperienced
> programmers to substitute them for clear thinking and
> well-written programs. The program I have been working
> on for several weeks was brought to me because it is
> nearly impossible for two "expert" users to get the program
> to run the same way twice in a row, or--sometimes--to
> even run at all. It depends entirely on what order things
> are done and the current phase of the moon. Mostly, this
> is because of the indiscriminate use of Common blocks,
> and the fact that the left hand doesn't always know what the
> right hand is doing.
>
> If I saw a COMMON block in a program written by JD Smith
> or Craig Markwardt, I probably wouldn't even think twice.
> But when I open an e-mail and there is someone pleading for
> "help" and I see Common blocks, I head straight for the
> liquor cabinet.
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Ok, agreed. It is not that I am not on your side, it is just that I
use common blocks for the above stated reasons and I cannot think of
any other way of doing it without reading in the data every time I
want to plot it in a different way.

Anyway, have a good weekend.

Cheers
Lasse

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[Message index]

		Re: variables in common blocks By: David Fanning on Fri, 04 May 2007 09:48
		Re: variables in common blocks By: Christopher Thom on Fri, 04 May 2007 09:40
		Re: variables in common blocks By: David Fanning on Fri, 04 May 2007 09:03
		Re: variables in common blocks By: lasse on Fri, 04 May 2007 08:56
		Re: variables in common blocks By: Foldy Lajos on Fri, 04 May 2007 08:36
		Re: variables in common blocks By: David Fanning on Fri, 04 May 2007 08:16
		Re: variables in common blocks By: Maarten[1] on Fri, 04 May 2007 08:07
		Re: variables in common blocks By: lasse on Fri, 04 May 2007 07:42
		Re: variables in common blocks By: David Fanning on Fri, 04 May 2007 07:11
		Re: variables in common blocks By: lasse on Fri, 04 May 2007 07:06
		Re: variables in common blocks By: David Fanning on Fri, 04 May 2007 06:45

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