ex11 - brain dump 3

Joachim Durchholz <>
Mon Jan 19 11:40:05 CET 2004


Vlad Dumitrescu wrote:
> Input events are easy to abstract out, because
> they're just messages;

Not sure what exactly you mean, but there's more than meets the eye with 
input events.
You need at least two levels of events:
1) Basic IO: key press, key release, mouse button press/release, mouse move.
2) "Predigested" events: mouse click, double click, drag (and subsequent 
drop), keypress, keeping a key pressed, change in shift-lock state, etc. 
etc.
3) High-level events: when a window area is uncovered and must be 
redrawn, when the user selects a different color scheme, to be applied 
to all applications, when the user logs out, when the computer is about 
to be shut down, when the contents of a text field changes, etc. etc. etc.

This is just a list of things that *can* be done using events 
(incidentally, it's a list of the more whacky messages from MS Windows). 
Many of these events aren't needed if everything is done in a language 
that's better than C; however, there are many situations when a 
"callback" (implemented by whatever means: messages, virtual functions, 
a parameter/attribute of function type) is the best answer.

Just my 2c.

Regards,
Jo
--
Currently looking for a new job.




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