On 04/28/2010 07:38 PM, bearophile wrote:
Andrei Alexandrescu:
I'm having trouble picturing the following scenario for a day in
life.
After your experience with Loki, what do you think about double
dispatch in external functions in D3?
Good question. Statistically, I'd say very few people are interested in
double dispatch. I've received reams of feedback from readers. Only a
couple inquired or mentioned the double dispatch chapter at all. This is
a bit odd because I think Loki's offering for double dispatch is
comprehensive. It also had a few bugs in it that went unnoticed for a
long time, which to me suggest very few actually needed that code.
Of course that's just a data point of sorts.
If we're to discuss double dispatch, I think we should first look at
library solutions and at ways to improve the language to allow general
solutions to categories of problems instead of cutesies like @virtual
function parameters.
Above all, I think at this time we should go with improving the language
definition and the quality of the compiler. There are quite a few
strident notes in the current definition. Overloading is not taken care
of properly, protection levels are underspecified and underimplemented,
property syntax is broken, tuples are a mess. Also there's no 64-bit
implementation. All that stuff is important and relatively urgent.
Andrei
