> Firstly, some ncurses calls return a *WINDOW and others take one as
> an argument but you never actually look at the contents of one
> yourself. I have defined "data Window = Window" and am using Ptr
> Window for the types of these. However, this means I get a warning
> about an unused constructor. Is there a better way to do this?
Hugs supports:
data Window
and I believe GHC and NHC do too. (Malcolm, SimonM: please shout if I
overstate.)
> Secondly, does anyone have any suggestions on how to provide an
> interface to this?
> void getyx(WINDOW *win, int y, int x);
> The getyx macro places the current cursor position of the given
> window in the two integer variables y and x.
> The type would probably ideally be "Ptr Window -> IO (CInt, CInt)".
The easy way is to use GreenCard (the other ffi frontends may be of
use too).
Or, you can do what GreenCard does which is to add 3 wrapper functions
more or less like this:
static int x;
static int y;
void wrap_getyx(WINDOW *win) { getyx(win,x,y); }
int getx(void) { return x; }
int gety(void) { return y; }
or what GreenCard used to do which is more or less
struct result { int x, int y };
void wrap_getyx(WINDOW *win, struct result *r) {
getyx(win,&(r->y),&(r->x));
}
getyx :: Ptr Window -> IO (CInt, CInt)"
getyx w = do
r <- alloc sizeof_result
wrap_getyx w r
x <- deref r 0
y <- deref r 1
free r
return (y,x)
or guess/check that getyx is really, really cheap to call and write two
wrappers gety and getx.
--
Alastair Reid
[EMAIL PROTECTED]
http://www.reid-consulting-uk.ltd.uk/alastair/
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