Re: [TCLCORE] biweekly telco on14th of July at 12:00 UTC

[da S. P. J <pet...@fl...>]

I don’t think the implementation matters, what I mean is that functionally it’s a specialized array/dict.

From: Emiliano <emi...@gm...>
Date: Wednesday, July 16, 2025 at 11:48
To: da Silva, Peter J (USA) <pet...@fl...>
Cc: tcl...@li... <tcl...@li...>
Subject: Re: [TCLCORE] biweekly telco on14th of July at 12:00 UTC
On Wed, 16 Jul 2025 14: 15: 46 +0000 "da Silva, Peter J " <peter. dasilva@ flightaware. com> wrote: > Is this a specialized array/dict? There seems considerable overlap. No, it isn't. As specified in TIP 369, the payload of the cargo command


On Wed, 16 Jul 2025 14:15:46 +0000

"da Silva, Peter J " <pet...@fl...> wrote:



> Is this a specialized array/dict? There seems considerable overlap.



No, it isn't. As specified in TIP 369, the payload of the cargo command is

a dictionary, so I used a dict Tcl_Obj, but could have used a hash table.



Quoting the TIP:



"It is proposed that a cargo subcommand be added to most widgets that will allow the user to store data related to the widget in a data dictionary. With the cargo command there are three parameters that can go with it: set, unset, and get.



Set adds and alters entries in the cargo dictionary.



    pathName cargo set name value ?name value ...?

"



Nothing special here. The main point is coupling the data lifetime to

widget lifetime. The difference is syntax; it would become



    $cargocmd set pathName name value ?name value ...?



A simple use case is the tooltip package: it holds the display data in an

array, indexed by widget name and, optionally, by a tag or index, separated

by a comma. When a widget with an entry in the array is destroyed, no

automatic cleanup is done; one must call the cleanup subcommand to delete

the data. If the package used a cargo table instead, the cleanup is

automatic.



Regards

--

Emiliano <emi...@gm...>