std.patterns: it was about time

[Chris Nicholson-Sauls]

Andrei Alexandrescu wrote:
> In wake of the increasing power of templates in D2, I am starting the 
> std.patterns module, which is to contain boilerplate for a number of 
> common design patterns (as in the GoF book). For now I'm adding a 
> Visitor implementation, which was lying in my codebase for a while.
> 
> http://ssli.ee.washington.edu/~aalexand/d/web/phobos/std_patterns.html
> http://ssli.ee.washington.edu/~aalexand/d/web/phobos/std_patterns.d
> 
> Comments and suggestions are as always welcome.
> 
> 
> Andrei

It was, indeed, about time.

Simple as it is, you might as well toss a Singleton mixin in there.  Its 
so common and so insanely simple that there may as well be an "official" 
one.

Observer should be an interesting one to try implementing.  It could 
make use of signals/slots to good effect.  The question there is in 
whether one is to observe a Foo or a particular property of a Foo.  Both 
should probably be available.

-- Chris Nicholson-Sauls