On Fri, Nov 13, 2009 at 11:38 AM, Tomas Lindquist Olsen <tomas.l.ol...@gmail.com> wrote: > On Thu, Nov 12, 2009 at 8:24 PM, Bill Baxter <wbax...@gmail.com> wrote: >> On Thu, Nov 12, 2009 at 10:46 AM, Tomas Lindquist Olsen >> <tomas.l.ol...@gmail.com> wrote: >>> On Tue, Nov 10, 2009 at 1:27 AM, Bill Baxter <wbax...@gmail.com> wrote: >>>> On Mon, Nov 9, 2009 at 4:09 PM, Walter Bright >>>> <newshou...@digitalmars.com> wrote: >>>>> Looks like Bill Baxter is giving a presentation on D Nov. 18! >>>>> >>>>> http://www.nwcpp.org/ >>>> >>>> Yep, that's right, and I'd be quite grateful to you smart folks here >>>> if you could share your meta-programming favorites with me! If >>>> you've got a real-world example of meta-programming in D that you >>>> think is particularly handy, then please send it my way >>>> >>>> I'm looking for small-but-useful things that are easy to explain, and >>>> make something easier than it would be otherwise. Things like places >>>> where static if can save your butt, or loop unrolling, and passing >>>> code snippets to functions like in std.algorithm. >>>> >>>> Things like a compile-time raytracer or regexp parser (though quite >>>> cool!) are not what I'm after. Too involved for a short talk. >>>> >>>> --bb >>>> >>> >>> I think tuples are a good example of something that makes your life >>> easier, lately I've been very fond of this little snippet: >>> >>>>>>>>>>>>>>>>>>>>>>>>> >>> >>> void delegate() Bind(Args...)(void delegate(Args) dg, Args args) >>> { >>> struct Closure >>> { >>> Args arguments; >>> void delegate(Args) callee; >>> void call() >>> { >>> callee(arguments); >>> } >>> } >>> >>> auto c = new Closure; >>> >>> // foreach not strictly necessary, but ldc currently chokes on >>> just an assignment... I should fix that.. >>> foreach(i,a;args) >>> c.arguments[i] = a; >>> c.callee = dg; >>> >>> return &c.call; >>> } >>> >>> class C >>> { >>> void foo(int,float) {} >>> } >>> >>> void main() >>> { >>> auto c = new C; >>> auto dg = Bind(&c.foo, 1, 2.0f); >>> // register delegate somewhere >>> } >>> >>> <<<<<<<<<<<<<<<<<<<<<<<< >>> >>> Not sure if this gets easier in C++0x , haven't read up on that... >> >> I think it does. C++0x has variadic templates. And some kind of >> lambdas/closure thing. So probably it can do something similar. >> Anyway, the meta- aspect of Bind seems kinda weak. Certainly a nice >> use of variadic templates and closures, though. >> >> --bb >> > > Just read the Wikipedia entries on Metaprogramming and > Template_metaprogramming, I guess I wasn't really aware of the > difference. > Seems a lot harder to come up with small real-world snippets of the former.
The way I read it, template metaprogramming is a kind of metaprogramming. Metaprogramming using templates. And ctfe/string-mixin metaprogramming are another, macro metaprogramming another etc. I think the phrase "template metaprogramming" just took particularly strong hold because of C++ where templates are always required for accomplishing pretty much any kind of metaprogramming. --bb
