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Ticket UUID:	929a918ec1b4adf0381fc1fc4609297185019ba8
Title:	docs should say oo::configurable can only be mixed in with oo::configurable
Type:	Bug	Created on:	2024-07-09 10:04:54
Submitter:	mnsummerfield	Assigned to:	nobody
Subsystem:	69. Other	Severity:	Minor
Priority:	5 Medium	Last modified:	2024-09-17 08:51:28
Status:	Open	Closed by:	nobody
Resolution:	None	Closed on:
Version:	9.0b2

Description:
Page: https://www.tcl.tk/man/tcl9.0/TclCmd/configurable.html#M5 This is the description section. I suggest adding a sentence something like: Note that oo::configurable classes can only be mixed in (using `mixin`) with _other_ oo::configurable classes, not with plain oo::class classes. The reason for suggesting this is that I tried mixing in an oo::class with an oo::configurable and got a very confusing "unknown method "configure":" error message.
User Comments:
oehhar added on 2024-07-09 10:34:02: Great ! Could you give a somple sample for the error case. Maybe, the issue is not intentional or the error message may be imporved. Thanks, Harald dmcooke added on 2024-09-03 20:24:28: This is because the `mixin` slot works by replacement by default. So the bare statement `mixin V` replaces the `::oo::configuresupport::configurable` mixin that the `oo::configurable` metaclass adds. It should work if you use `mixin -append V` instead. I don't know why `mixin` defaults to replacement, instead of appending (like `variable` does). It doesn't make any sense. dkf added on 2024-09-17 08:51:28: The real problem comes if someone joins two class hierarchies that use the property list slots in different ways (such as `oo::configurable` and some of the stuff that's been mooted for Tk megawidgets, though in that case they also fight over the meaning of `configure` as a method). There really isn't a good way around that. I guess we need a bit better documentation to describe the limits of what's possible.

Attachments:

obj5-bad.tcl [download] added by mnsummerfield on 2024-07-10 07:18:20. [details]