[Scummvm-devel] Simplifying keyboard repeat

[Max Horn]

Am 19.05.2006 um 13:18 schrieb Marcus Comstedt:

>
> Max Horn <max at quendi.de> writes:
>
>>> The SCUMM help text for example lists Ctrl 0-9, Alt 0-9, Alt x, Ctrl
>>> z, Alt Enter, Ctrl d, Ctrl s, Ctrl f, Ctrl g, Ctrl m, Ctrl Alt 1-8,
>>> Ctrl Alt +, Ctrl Alt - and Ctrl a.  Yet only a few of these are
>>> implemented by the SCUMM engine itself.
>>
>> You are mixing engine specific hotkeys with backend specific hotkeys.
>
> No, I'm not.  engines/scumm/help.cpp is.  I just extracted the
> list from there.

Oh my god, the help dialog in the SCUMM engine :-). Does anybody even  
maintain that? :-).

[...]

> Well, I haven't even checked the actual docs,
You should, though.

> I'm just comparing the
> on-line help text with what is actually implemented by the code which
> contains it.  As I said, mismatches can be remedied both by removing
> text and by adding implementation, but I don't think it's all that
> clear cut that any mismatches are due to "suckfullness" of the
> documentation.

But it does. Or rather in this case, it documents the "uber- 
suckfullness" / "lameness" of that help dialog. It can't be fixed by  
changing the backends / engines, either -- some backends simply  
*never* will have those hotkeys, ever! So the help dialog *does*  
suck, the issue is orthogonal to whether and how we implement certain  
backend specific hotkeys.

[...]

>> You mean adding those three lines to a couple dozen event loops
>> spread over 11 engines, vs. adding it only in the DC backend (and
>> maybe the X11 backend, should it ever implement aspect ration
>> correction) ? Somehow I fail to see how this is "better" in about any
>> regard... :-)
>
> I'm trying to convince you that having _one_ implementation, and not
> spreading it out _at all_, is better.  Remember?  ;-)

Sure, I do. Do you remember my question? I'll repeat it for you:  
"Marcus, could you give a list of all hotkeys that you think should  
be shared, and state which ports would share them?"

>   Today it's
> three(?) backends which would need the three lines,

It's two backends. From the list you have given so far (i.e.: Ctrl-A.  
And nothing else), your proposal is to add a function which  
essentially does this:
bool handleCommonHotkeys(Event evt) {
   if (hotkey = ctrl-a)
     toggle aspect correction
     return didHandle;
   else
    return didNotHandle;
}

and then modifying those *two* backends to call that function.

> how many tomorrow?

Good question. From where I am at, the best guess I can come up with  
is "likely 0, if not, we can rediscuss this".

> What about the next time such a generic hotkey is added?

Yeah, let's see, in the past 4 years, we added one, we should prepare  
for the second one which is due 2008 :-)


Look, I am all for factoring out shared code when it makes sense, in  
fact a lot of the work I have done in the past years on ScummVM  
revolves around exactly that. But the stress here is on "where it  
makes sense". I think to justify factoring out something, it has to  
be either repeated several times, or has to be complicated. But a  
*trivial* code check, that is used in two places, doesn't quite fill  
that role for me. That's why I ask: Are there other candidates? If we  
have 3-4 hotkeys that are shared by at least 2 backends, we can talk  
this. But it's silly to do that for the single case you have  
suggested so far. To me, it clearly falls into the category "needless  
overdesign".


Cheers,
Max