OpenEuphoria

Re: Win32lib dialogs within proc's

• Posted by Matthew Lewis <MatthewL at KAPCOUSA.COM> Mar 10, 2000
• 418 views

> From: Irv Mullins
>
> Ermm. I have dozens of such "user built dialogs" in my programs.
> I just build a new window, place an edit text and/or checkboxes or
> radio buttons as needed, and probably an "OK" button and a "cancel"
> button, which when clicked transfer the info or do the task
> called for,
> then close the window.
>
> I'm trying to think of where something like this would be
> needed. So far,
> nothing comes to mind.
>

I seem to have solved my problem, but here's what I'm doing.  I'm working on
writing a game that's basically like Magic the Gathering (a fantasy card
game--and actually the reason I started using Euphoria a couple of years
ago).  Each card has it's own special procedures for doing whatever the
card's effects are in the game.  For instance, when you cast a Lightning
Bolt, you then choose a target, and the Lightning Bolt does some damage to
whatever your target was.  Well, I've got a ton of procedures that need to
do such a thing.  In order to find out what the target is, I need to open up
the window, and once the window is done, go right back to the spot in the
card's event code.  If I simply open the window, it comes right back to the
code, without giving the user a chance to respond.


>
> Actually, there shouldn't be many globals required. Perhaps
> you need to
> reconsider
> how your program functions. In Windows, there's generally _not_ a main
> flow -
> just a state that is modified in response to events, and perhaps some
> procedures that
> are run on demand.  (sort, print, etc)
>

I've definitely considered this, but I haven't come up with any satisfactory
solutions yet.  At least, not without completely rewriting the basic engine
of the game...

In any case, I hacked win32lib, and came up with something that seems to
work.  I created a procedure called EventLoop, which just runs an extra
event loop on top of WinMain's (in fact, EventLoop is just WinMain
modified).  When you've finished with the Loop, you just set the last value
of EventLoopExit to true, and it ends, and you continue.  This should allow
multiple nested loops, using EventLoopExit as a stack of flags.  A definite
caveat is that win32lib won't detect if you've closed down the main window
(to exit the program) from within the event loop.


global sequence EventLoopExit
global procedure EventLoop( integer id, integer style )
-- main routine
    atom hWnd
    atom msg
    atom ele

    -- allocate a message buffer
    msg = allocate_struct(SIZEOF_MESSAGE)

    EventLoopExit &= 0
    ele = length(EventLoopExit)
    openWindow( id, style )

    -- message loop
    while c_func( xGetMessage, { msg, NULL, 0, 0 } )  and not
        EventLoopExit[ele] do
        c_proc( xTranslateMessage, { msg } )
        c_proc( xDispatchMessage, { msg } )
    end while
    EventLoopExit = EventLoopExit[1..ele-1]
end procedure