[Tcl-bugs] [ tcl-Feature Requests-2549883 ] Tcl_CreateEnemble() lacks ClientData, Tcl_CmdDeleteProc args

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Feature Requests item #2549883, was opened at 2009-01-30 18:23
Message generated for change (Settings changed) made by dkf
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Category: 21. [namespace]
Group: None
>Status: Closed
>Resolution: Rejected
Priority: 5
Private: No
Submitted By: Don Porter (dgp)
Assigned to: Donal K. Fellows (dkf)
Summary: Tcl_CreateEnemble() lacks ClientData,Tcl_CmdDeleteProc args

Initial Comment:

Seems there's no way when creating an
ensemble command to set a Tcl_CmdDeleteProc.

Either a revised interface permitting that,
or some advice in the documentation about
how to proceed in light of this disability
(delete trace?  CmdInfo manipulation?) would
be in order.



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>Comment By: Donal K. Fellows (dkf)
Date: 2009-07-13 13:33

Message:
Can also use Tcl_SetEnsembleParameterList to install global extra arguments
to every subcommand. If that's not sufficient, it really is time to get
busy with TclOO instead.

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Comment By: Donal K. Fellows (dkf)
Date: 2009-02-23 10:51

Message:
There is one way to do it now: attach the clientData to the individual
subcommands in the ensemble. But the C OO routines are probably easier
overall, especially if you're not interested in supporting inheritance.

Everything in the OO code is NRE-enabled.

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Comment By: Don Porter (dgp)
Date: 2009-01-31 18:09

Message:
The intended use case was to convert the
slave interp command returned by [interp create]
into an ensemble.  The motivation for that was
to assist the NRE-enabling of [$slave invokehidden]
to fix Tcl Bug 2486550.

Since I opened this, I've learned more about NRE
and it's now clear that conversion to an ensemble
is not necessary, and not really even very helpful
in tackling 2486550, so this particular motivating
case is no longer active.

Now consider it just a feature request for extensions.
If an extension wants to create an object-like command,
is there a recommended way to build on Tcl_CreateEnsemble()
to achieve that?  Or is it recommended to use the OO
C routines instead?


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Comment By: Donal K. Fellows (dkf)
Date: 2009-01-31 15:26

Message:
Try explaining the use-case for this significant increase in complexity
first. :-)

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Comment By: Don Porter (dgp)
Date: 2009-01-30 19:21

Message:

well, access to these things is
denied because the ensemble machinery
itself is making use of them.  So
what's the way to implement an object-like
command?


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Comment By: Don Porter (dgp)
Date: 2009-01-30 19:18

Message:

Also no way to set a ClientData.

Without these things, appears very hard
to use the public access to ensemble machinery
to create an object-like command.

Maybe I'm barking up the wrong tree, and
should be putting oo facilities to work
instead?


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Comment By: Don Porter (dgp)
Date: 2009-01-30 18:24

Message:

This disability leaks through to the
internal TclMakeEnsemble() utility as well.

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