Le 27/08/2012 00:41, Walter Bright a écrit :
On 8/26/2012 3:26 PM, Manu wrote:
I just updated to 2.60 and found errors throughout my code where function
pointers default args no longer work.
_Every single project_ I've written in D, 5 projects, don't work anymore,
including my projects at work.
I found this discussion:
http://d.puremagic.com/issues/show_bug.cgi?id=3866
It seems the change was just decided and implemented with basically no
discussion or argument at all :/
My use cases are dynamic linkage, and cross-language integration.
I can't manually interact with DLL's containing API's that expect to have
default arguments if function pointers no longer support them.
Also when receiving foreign language function pointers, they
frequently need to
have default args too.
I also integrate with many C style API's (rendering engines and the
like), which
involve registration of various callbacks, and lots of those have
default args too.
I find this particularly surprising, since I recently motivated
implementation
of new traits which could parse default args from parameter lists, and
use that
to generation function pointers in templates which auto-magically clone
functions parameter lists verbatim, specifically including the default
args...
The trouble is that, as 3866 shows, there is no design anyone could come
up with that worked in a consistent manner. The only consistent way out
was to make default arguments a characteristic of the declaration, not
of the type.
The trouble for function pointers, is that any default args would need
to be part of the type, not the declaration.
I know it broke code (for many others, too), and I'm very sorry about
that, but I don't see another way out.
(Many uses of default arguments can be replaced with overloaded functions.)
That guy just have to rework 5 projects. This is quite a lot of work.
Obviously, that change have to be done. But you can't just impose such a
change on users. Their agenda isn't synchronized with D's.
D NEED a better versioning scheme, as explained MANY times here already.
