comp.lang.idl-pvwave archive: archive » Storing !NULL in struct

Home » Public Forums » archive » Storing !NULL in struct

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

Re: Storing !NULL in struct [message #83596 is a reply to message #83531]

Mon, 18 March 2013 12:33

Michael Galloy
Messages: 1114
Registered: April 2006

Senior Member

On 3/18/13 12:26 PM, Yngvar Larsen wrote:
>
> This is not the case for lists, as already discussed:
>
> IDL> larr = list(length=10) & for n=0, 9 do larr[n] = {foo: 0}
> IDL> print, larr[0].foo
> 0
> IDL> larr[0].foo = 4
> % Attempt to store into an expression: Structure reference.
> % Execution halted at: $MAIN$
>
> I fail to see why the latter isn't allowed.

I agree.

> This means that if you still want to modify structures within your list, you need to do something like this
>
> IDL> tmp = larr[0]
> IDL> tmp.foo = 4
> IDL> larr[0] = tmp
> IDL> print, larr[0].foo
> 4
>
> This seems silly to me. What is the purpose of not allowing this?
>
> Switching to hash tables instead of structures as general purpose data structure is of course a very good strategy in 2013, but I have at least 10 years worth of legacy code which already heavily (mis-)uses the anonymous structure as a "hash table light" with case insensitive keys.

I agree here as well. But, I do find it difficult to use new IDL
features for long after they are no longer new since so many users do
not have the latest version of IDL.

Mike
--
Michael Galloy
www.michaelgalloy.com
Modern IDL: A Guide to IDL Programming (http://modernidl.idldev.com)
Research Mathematician
Tech-X Corporation

Report message to a moderator

[Message index]

		Storing !NULL in struct By: tom.grydeland on Tue, 12 March 2013 05:09
		Re: Storing !NULL in struct By: Yngvar Larsen on Tue, 19 March 2013 01:59
		Re: Storing !NULL in struct By: Bob[4] on Mon, 18 March 2013 20:26
		Re: Storing !NULL in struct By: Michael Galloy on Mon, 18 March 2013 12:33
		Re: Storing !NULL in struct By: Yngvar Larsen on Mon, 18 March 2013 11:26
		Re: Storing !NULL in struct By: Michael Galloy on Mon, 18 March 2013 09:48
		Re: Storing !NULL in struct By: tom.grydeland on Mon, 18 March 2013 05:40
		Re: Storing !NULL in struct By: lecacheux.alain on Mon, 18 March 2013 05:20
		Re: Storing !NULL in struct By: tom.grydeland on Mon, 18 March 2013 04:41
		Re: Storing !NULL in struct By: lecacheux.alain on Mon, 18 March 2013 02:27
		Re: Storing !NULL in struct By: tom.grydeland on Mon, 18 March 2013 02:00
		Re: Storing !NULL in struct By: penteado on Fri, 15 March 2013 16:14
		Re: Storing !NULL in struct By: chris_torrence@NOSPAM on Fri, 15 March 2013 13:40
		Re: Storing !NULL in struct By: Michael Galloy on Fri, 15 March 2013 11:51
		Re: Storing !NULL in struct By: kagoldberg on Fri, 15 March 2013 09:40
		Re: Storing !NULL in struct By: Lajos Foldy on Fri, 15 March 2013 07:02
		Re: Storing !NULL in struct By: lecacheux.alain on Fri, 15 March 2013 06:31

Previous Topic:	HASH makes too many temporaries
Next Topic:	MGlib IDL library

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 15:26:01 PDT 2025

Total time taken to generate the page: 2.40709 seconds