On Monday, 14 May 2012 at 11:08:09 UTC, Stephen Jones wrote:
I have a Widget interface which I was hoping would allow me to
subsume a set of classes {Button, Cursor, etc} as being Widgets
so I could keep an array of buttons, cursors, etc by
initializing
them as Widgets.
private Widget[] widgets;
...
widgets[widx++]=new Button(fmt, unitw, unith, count);
...
widgets[widx++]=new Cursor(unitw, unith, count);
But when I try to step through the array I cannot access Button
or Cursor variables because "Error: no property 'vertStart' for
type 'Widget.Widget'":
foreach(Widget w; widgets){
glDrawArrays(GL_TRIANGLES, w.vertStart, w.vertCount);
}
I am used to languages where the w under consideration in any
iteration would be known to have been initialized as a Button or
Cursor, etc, and the value of vertStart would be found without
error. I cannot cast without wrapping everything in if
statements. I could use access functions but I would prefer not
to incur function overhead. Is there a solution?
Are you compiling with the -property switch? If so, vertStart and
vertCount must be declared with the @property attribute.
Otherwise invoke them like regular functions, i.e., vertStart() /
vertCount().
