Le 27/08/2012 18:02, Michal Minich a écrit :
On Monday, 27 August 2012 at 15:00:11 UTC, deadalnix wrote:
/!\ Shameless autopromotion incoming /!\
I have recently put some effort into exploring alternatives to visitor
pattern and see what can be done in D. I ended up with a solution
which is a real improvement compared to plein old visitor pattern and
wanted to share this here.
I think this is short enough to be a good example to show what can be
done with D capabilities.
http://www.deadalnix.me/2012/08/25/visitor-pattern-revisited-in-d/
This is nice use of d magic. If the implementation could recompute the
functions pointers during compilation, this seems as nice generally
function. This makes me thing of computed goto (to functions)
One possibility to achieve this result for visitor is to use mixin.
I would mixin implementation of accept method into very node super
class. This is to avoid code duplication.
Secondly, I would mixin implementation of opDispatch that simply does
nothing/throws to every implementation of visitor. This is to avoid
empty implementations of visit methods which are not needed for
particular visitor.
This can only work if you know all node type by advance. Which is one
limitation of the visitor pattern I intended to solve.
