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Subject: half-idea for #ifdef and key deifnition hell...

half-idea for #ifdef and key deifnition hell...

From: Jonathan Gordon <>
Date: Wed, 22 Mar 2006 20:18:42 +1100

hey all,
ok, so i had a few min on the throne before and i was thinking about
how to make the keypress code nicer (and get rid of those bloody
painful _PRE definitions..)

ok, so just remember, this idea isnt 100% done and prob has flaws, but
thats why im putting it on the list.. so we can argue about it and
make it workable..

so, my idea is to sort of emulate the menu code...
youd have something like
struct {
int button_code;
bool needs_pre;
int ret_code;
function* function_to_call;
} Button_Choice;
where cutton_code is the #define of the button you want to get,
needs_pre will check that the last button was the _pre definition
(which in this would be the array item prior to this one), ret_code
would be the value to return, ill explain the reason in a sec, and
function_to_call is the function to call when this key is pressed
(instead of having a switch afterwards), this would of course be
skipped if its NULL;

so, then youd use it something like
static struct Button_Choice [] {
    { GENERIC_LEFT, 0, 1, NULL},
    { GENERIC_RIGHT, 0, 2, NULL},
    { GENERIC_ENTER,1, 4, NULL},

then, instead of calling button_get() or whatever it is, you call
another function do_button_choice(struct Button_Choice *buttons, int
num_choices, int &last_button, int time_out) where last_button is used
to store the last_button so the _PRE things work, we could use a
static variable here, but this way means we can call it in a "nested"
sort of fasino... although, just typing this now, im not sure this is
needed... and timeout sets the button timeout before returning...

in that function it would call get_button with the timeout setting..
if get_button returns BUTTON_NONE then the funciton immediatly returns
BUTTON_NONE also. otherwise it goes through the list and if the button
that was pressed is in the list it checks if it needs _pre, if it does
and the last button was not pre then im not sure what it should
return.. (maybe it should keep going through the list and check if the
same definition exsists but without needs_pre? otherwise return
if the button is found (and if it needs _pre and it was the last
button) if it has a function to call it returns that functions return
value (or not?) otherwise it returns that items ret_code value.
now the reason we need that and not do like the menu and just return
the item index is so we dont have any #ifdef 's in the switch but can
still use them when adding items...

does this sound workable? would it make life easier and actually be a
good replacement for the current system?

my only concern is that it may not be fast enough... but if its not,
then where key press speed is really needed (i.e games), they can call
get_button() manually...
Received on 2006-03-22

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