I'm coming up against some interesting challenges while porting stuff in my utility
library to D2.
Firstly, D2 uses opBinary and opOpAssign, rather than the operator-specific op* and
op*Assign. While the latter still work, they aren't mentioned in the current D2 docs.
Which would imply that they're on the way out; however, there's no mention at
https://github.com/D-Programming-Language/d-programming-language.org/blob/master/deprecate.dd
(See also
http://d.puremagic.com/issues/show_bug.cgi?id=7779 )
Still, it seems clear that opBinary/opOpAssign is the D2 way of doing it. But it has the
drawback that, because it's a template, it isn't virtual. One way about it is to keep the
D1-style op functions and make opUnary/opBinary/opOpAssign call these. But is there a
better way?
The other isn't a D2-specific issue, though D2 increases the significance of it. I have a
method with the signature
Set opAnd(bool delegate(Element) dg)
I would like to enable a user of the library to pass in a delegate whose parameter is any
type to which Element is implicitly convertible. This could be the same type as Element
with the top-level constancy changed (probably the main use case), or a type that is
distinct beyond the constancy level. Turning it into a template
Set opAnd(E)(bool delegate(E) dg)
would address this, but prevent overriding with the appropriate code for each set
implementation.
Who else has been faced with this problem? Have you found a good way of
dealing with it?
Stewart.
