1. Case/switch
Kat brought up case/switch. I'd love to see this become part of the
language.
I was writing an artificial life program for Windows. Basically, it was
a bunch of buttons in a grid. If a button was "hot", the program would
check to see whether the button in the row above and to either side was
"hot" to determine whether to make that button itself "hot".
Well, as you can imagine, that works fine for the buttons in the middle
of the grid. But when you get to the buttons in the grid above, you have
to check to see if a button is at a window edge. So there are a lot of
"if button1 = leftedge or button2 = rightedge" kind of stuff. It got
really tedious. The only think I could think was "This would be so much
easier with a Case statement".
Is there some easy way to do that that I'm missing?
2. Re: Case/switch
----- Original Message -----
From: "SR.Williamson" <writeneu at hotmail.com>
To: "EUforum" <EUforum at topica.com>
Subject: Case/switch
>
> Kat brought up case/switch. I'd love to see this become part of the
> language.
>
> I was writing an artificial life program for Windows. Basically, it was
> a bunch of buttons in a grid. If a button was "hot", the program would
> check to see whether the button in the row above and to either side was
> "hot" to determine whether to make that button itself "hot".
>
> Well, as you can imagine, that works fine for the buttons in the middle
> of the grid. But when you get to the buttons in the grid above, you have
> to check to see if a button is at a window edge. So there are a lot of
> "if button1 = leftedge or button2 = rightedge" kind of stuff. It got
> really tedious. The only think I could think was "This would be so much
> easier with a Case statement".
>
> Is there some easy way to do that that I'm missing?
>
As a general principle, I try to use a data-oriented programming style. In
the case (no pun intended) you describe, you could try something like
this...
--------------
function doTopLeft( ... )
. . .
end function
function doTop( ... )
. . .
end function
function doTopRight( ... )
. . .
end function
.
.
.
function doMiddle( ... )
. . .
end function
constant TL = routine_id("doTopLeft"),
TP = routine_id("doTop"),
TR = routine_id("doTopRight"),
.
.
.
MD = routine_id("doMiddle")
-- For each button in the grid, you assign it's position handler.
-- Assuming you have a sequence holding the button ids and
-- another for the position property.
sequence GridBtns, GridPosns
GridBtns = repeat(0, ButtonCount)
GridPosn = repeat(0, ButtonCount)
for i = 1 to GridWidth do
for j = 1 to GridHeight do
if i = 1 then -- top row
if j = 1 then
x = TL -- top left
elsif j = GridHeight then
x = BL -- bottom left
else
x = LF -- left
end if
elsif i = GridWidth then
if j = 1 then
x = TR -- top right
elsif j = GridHeight then
x = BR -- bottom right
else
x = RT -- right
end if
else
if j = 1 then
x = TP -- top
elsif j = GridHeight then
x = BT -- bottom
else
x = MD -- middle
end if
end if
-- Calc the index for the position.
z = (j-1)* GridWidth + i
GridPosn[z] = x
next
next
-- Once this data is initialised, in the click handler do this.
procedure onClickBtn()
integer b
object rc
b = find(getSelf(), GridBtns)
rc = call_func( GridPosn[b], { . . .})
.
.
.
end procedure
-------
The idea is that you do a once-only set up of data that you can quickly use
during the running of your code. This is much quicker than making the
position decision everytime a button is pressed. This way, you only make
that decision once (so long as the button doesn't move).
cheers,
Derek
