[MACTCL] Some progress getting Tk to work with Ruby

[Robert K. <ro...@ke...>]

All:

I have been doing some tinkering trying to get Jeff's new Tcl and Tk for 
Mac OS X to work with Ruby. I thought I'd share some thoughts about what 
I've think I've found so far in case it's of some help to those trying 
to get Tk to work with other scripting languages.

As background, I initially wrote directly to Jim a few days back saying 
I tried to run a Ruby script that used Tk and nothing showed up. He 
suggested I verify that DoActualWait was getting called to listen for 
events. You should also knno that while I've been learning Ruby, I'm no 
expert. Also, this is my first time looking at Tcl/Tk internals. Please 
take the suggestions below as such and feel free to correct any 
misunderstandings I might have.

When I first began to try to debug the problem, I noticed something odd. 
When I ran Ruby under gdb a Tk-window appeared with the two buttons that 
it's supposed to have. However, I couldn't do anything with it (like 
make it key, or close it). But, when run from the command-line without 
gdb the window doesn't show up at all. So, from there, I began to try to 
track down why DoActualWait() wasn't getting called...

SUGGESTED CHANGE TO tkMacOSXInit.c:TkpInit()
When a Ruby script that uses Tk starts up, it calls the following Tcl/Tk 
functions to get started:
	Tcl_FindExecutable
	Tcl_CreateInterp
	Tcl_Init
	Tk_Init
What I noticed is that there are some very important looking functions 
that only get called from tkMacOSXAppInit.c:main() or 
tkMacOSXAppInit.c:Tcl_AppInit(). Specifically, they are 
tk_MacOSXSetupTkNotifier(), TkMacOSXInitAppleEvents(interp), and 
TkMacOSXInitMenus(interp).

I would suggest that these three functions need to be called from 
TkpInit() which is the platform specific code called from Tk_Init.

SUGGESTED CHANGE TO tkMacOSXNotify.c:tk_MacOSXSetupTkNotifier()
When I first added tkMacOSXNotify to TkpInit() it didn't do anything. 
After some more code reading, I found this comment in 
tkMacOSXAppInit.c:main() that made that not so surprising:
<code_snippet>
     /*
      * NB - You have to swap in the Tk Notifier BEFORE you start up the
      * Tcl interpreter for now.  It probably should work to do this
      * in the other order, but for now it doesn't seem to.
      */
</code_snippet>

I would like to suggest that we add one line to the end of 
tk_MacOSXSetupTKNotifier() that reads:
	   TclInitNotifier();
It seems that by calling Tcl_SetNotifier, we update the pointers in 
tcl_stubs, but it doesn't seem to be sufficient because the 
ThreadSpecificData, tsdPtr, keeps a pointer to the tcl_InitNotifier that 
won't be updated unless we call TclInitNotifier. Furthermore, this 
guarantees that TkMacOSXInitNotifier() gets called. And, if you look at 
the source for tclNotify.c:TclInitNotifier() it becomes very clear why 
it was working iff we swapped in the notifier before the interpreter is 
created.

SO WHERE DOES THAT LEAVE ME ?
Well, acutally, not much better off :-( I can now guarantee that my 
event loop is running which is a Good Thing (TM). However, I still only 
see the window appear when I run under gdb. And when I click on the 
window I get a new message about SetFrontProcess failing with an error 
code of "-600".

I'm not familiar with Carbon's idea of processes and how to control, it 
but after reading the error message for "-600", I decided to try and 
call GetProcessInformation to find out more about the running process in 
hopes of finding out why I get different behavior in GDB and outside of 
GDB.

When I run outside of GDB, the process has the following properties:
LAUNCH DONT SWITCH
DESK ACCESSORY
MULTI LAUNCH
NEED SUSPEND RESUME
CAN BACKGROUND
DOES ACTIVATE ON FG SWITCH
GET FRONT CLICKS
LOCAL AND REMOTE HL EVENTS
STATIONERY AWARE

When I run inside of GDB, the process has these very different 
properties:
ONLY BACKGROUND
32 BIT COMPATIBLE
HIGH LEVEL EVENT AWARE

The "ONLY BACKGROUND" bit being set while running under GDB explains why 
it won't let the window be set to the front. However, I don't understand:
	a) why don't I get windows when running outside of GDB
	b) how can I control what these attributes are ? Are there Carbon 
functions to declare what I want them to be ?

Thanks in advance for any thoughts or help in figuring out what to 
tinker with next.

Robert Kedoin