comp.lang.idl-pvwave archive: archive » Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice!

Home » Public Forums » archive » Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice!

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! [message #72250 is a reply to message #72167]

Thu, 19 August 2010 12:35

Chris[7]
Messages: 4
Registered: August 2010

Junior Member

In reality, how many people actually use CATCH to handle the case of a
failed call to where? Maybe I'm off base here, but I'm guessing that
people either do something like

hit = where(data eq min(data)-1, count)
if count eq 0 then ....

or they don't check for a failure at all. In the former case, the code
still works fine in IDL 8. In the latter case, the data gets messed up
in an admittedly subtle way. But in that case, the "existing valid code"
isn't valid -- not checking the result of where is a bug. It wouldn't be
fair to blame IDL for that.

chris

On 8/19/10 1:57 AM, svhhaugan wrote:
> On Aug 18, 8:45 pm, "Jeff N."<jeffnettles4...@gmail.com> wrote:
>>> For IDL 8, the rules have suddenly been changed, with no warning
>>> and no way to turn it off (other than staying with version 7).
>>
>> I don't know how you can say there was no warning - ITTVIS has been
>> advertising the negative indexing feature for months now. And it was
>> completely obvious to me from the get-go that the new indexing would
>> have the effect on where() calls that you're talking about. It was
>> one of the first things I thought of.
>
> I guess we haven't been spending much time reading the advertising ;-)
> Anyhow, that's not the kind of warning I referred to.
>
> I think most researchers naively expect new features in a
> "programming
> language" to preserve the stated semantics of existing code, or at
> least
> provide (optional) warning mechanisms (compile-time or run-time)
> that'll flag those cases where the semantics have been changed.
>
> The help file for IDL 7 said "code similar to the following *can*
> be used to avoid errors", not "code similar to the following
> *should* be used, because we do not guarantee that an error will
> occur in the next version of IDL".
>
> Stein

Report message to a moderator

[Message index]

		Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! By: svhhaugan on Thu, 19 August 2010 04:57
		Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! By: jeffnettles4870 on Wed, 18 August 2010 11:45
		Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! By: svhhaugan on Wed, 18 August 2010 06:30
		Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! By: Haje Korth on Wed, 18 August 2010 05:30
		Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! By: Maarten[1] on Wed, 18 August 2010 05:14
		Re: Warning: IDL 8.0 alters the behaviour of existing valid programs without any notice! By: Chris[7] on Thu, 19 August 2010 12:35

Previous Topic:	exporting floats
Next Topic:	FITS WCS routines

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 11:00:05 PDT 2025

Total time taken to generate the page: 0.55769 seconds