On Wednesday, 28 March 2018 at 17:42:45 UTC, Steven Schveighoffer
wrote:
On 3/28/18 11:46 AM, Chris Katko wrote:
enum hasRotate = anySatisfy!( isa(pos), a); //if of type
"pos"
anySatisfy!(isa!pos, a)
anySatisfy takes a template alias (in this case, an
instantiation of isa with a specific type), and then applies
the template to all the elements of the alias sequence,
returning true if any statisfy.
-Steve
Yeah, that was one of my errors during my 4 AM binge. But I
forgot/missed to update that when I posted.
So far, everything is working with some dummy calls, and now I
just have to start doing the annoying work of writing the code.
It's just... I wish it was a little more elegant. Right now, I'm
stuck with like tons of static if cases. [see code at end of
post] If I add "centered position" vs "position" now, I have to
figure out how to add that into a single compound statement to
fit into a unique static if. As opposed to simply, "if centered
pos, take position, and just change it by subtracting width and
height." In that case, I can get away with leaving them run-time
statements, but more complex features not-so-much. The point is
to use compile-time/static/templates to build the correct
statement. Because at the core of what I'm doing... it IS all
statically / compile-time knowable information.
And having TONS of static ifs means there's TONS of room for
human error as its maintained.
If I wrote a Python/whatever script that pre-processed my D code
from the AST, I'd have no theoretical reason to prevent me from
doing this (though, clearly with much added frustration of
implementation and debugging!).
I'm starting to wonder if a mixin will somehow help... hmm. I'm
going to keep thinking about the problem.
Some code will probably help explain what I'm talking about:
funct2(g.tile_bmp, pos(100,100), scale(2), rotate(0.0f),
center());
template isa(T){enum isa(U) = is(U == T); }
void funct2(A...)(ALLEGRO_BITMAP *bit, A a)
{
enum hasPosition = anySatisfy!(isa!(pos), typeof(a));
enum hasCenteredPosition = anySatisfy!(isa!(center), typeof(a));
enum hasRotate = anySatisfy!(isa!(rotate), typeof(a));
enum hasScale = anySatisfy!(isa!(scale), typeof(a));
static if (hasPosition && hasCenteredPosition)
{
float temp_x=a[staticIndexOf!(pos, typeof(a))].x - bit.w/2;
float temp_y=a[staticIndexOf!(pos, typeof(a))].y - bit.h/2;
}else{
float temp_x=a[staticIndexOf!(pos, typeof(a))].x;
float temp_y=a[staticIndexOf!(pos, typeof(a))].y;
}
static if (!hasPosition)
{
assert(0, "Need to pass a position!");
}
static if (hasPosition && !hasRotate && !hasScale)
{
// Stuff
pragma(msg, "Class 1");
writeln("x ", a[staticIndexOf!(pos, typeof(a))].x);
writeln("y ", a[staticIndexOf!(pos, typeof(a))].y);
al_draw_bitmap(bit,
temp_x,
temp_y,
0);
}
static if (hasPosition && hasRotate && !hasScale)
{
// Stuff
pragma(msg, "Class 2");
writeln("x ", a[staticIndexOf!(pos, typeof(a))].x);
writeln("y ", a[staticIndexOf!(pos, typeof(a))].y);
al_draw_rotated_bitmap(bit,
bit.w/2,
bit.h/2,
temp_x,
temp_y,
a[staticIndexOf!(rotate, typeof(a))].a,
0);
}
static if (hasPosition && !hasRotate && hasScale)
{
pragma(msg, "Class 3");
}
static if (hasPosition && hasRotate && hasScale)
{
pragma(msg, "Class 4");
}
}
