Eric Niebler wrote:
Well, Boost has as wiki, so what's stopping you? :-)
U R RIGTH
[...] Oh, nothing at all. The benefit comes when declaring global primitives. Consider this at namespace scope:
namespace my { struct placeholder {}; proto::terminal<placeholder>::type const _ = {{}}; }
If terminal<>::type were a type with a constructor, that constructor would have to run *sometime* and the placeholder wouldn't be usable until after that time. Trouble is, C++ makes very few promises about when that *sometime* is. In contrast, the code above requires no runtime initialization. The placeholder just *is*, and there is no time during your program's execution when it is invalid to use it.
I got it. Thanx. Where in the wiki do we put that piece of information?
The only problem I had using MPL with proto was compile-time performance problems when using MPL lambdas. In order to keep compile times down, I've replaced as much template meta-programming in proto as possible with preprocessor meta-programming.
Could you publish an article about that? Your article "Conditional Love: Foreach Redux" (http://www.artima.com/cppsource/foreach.html) is a good example about cool things that are hidden in some innocent looking piece of code. Reading the header file never would have exposed the things that matter (at least to me).
I don't think that would make for an interesting article. See below.
Seems like leaping ahead is your daily bread. (a rhyme! I claim copyright on that one!) So for you it's crap and for me it's all new and cool stuff.
I'm sorry to disappoint you, but there is probably no way you can profit from proto's innards.
I disagree. If I understand what's inside I probably could make it do what Daixtrose did for me the last years: compile-time differentitaion of arbitray expressions with regard to every variable contained. If proto fits my needs I can put all my rewrite attempts to the garbage bin and spend time on using proto. So proto is what I want to learn and what I want to understand in-depth.
Apropos proto: are you planning to introduce a glommable disambiguation mechanism [Geoffrey Furnish]?
I Googled this: http://www.adtmag.com/joop/carticle.aspx?ID=627. IIUC, this is a way to control which sub-expressions can combine with which others, and with which operators. Proto can do this, and its mechanism is much more powerful and elegant, IMNSHO. You define the meta-grammar of your DSEL, and then you tell Proto that only expression types that conform to that meta-grammar are allowed. Operators that produce invalid expressions are not even considered.
First read this ("Patterns and Meta-Grammars"): http://tinyurl.com/3akbtb
That's for the usenet archive: http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost_proto/user_s_...
Then this ("Extending Proto"): http://tinyurl.com/2xs222
[ No critique, I simply love links that give me an idea of what was meant even in 10 years when tinyurl is down or lost. Adding this for future readers] http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost_proto/user_s_... Thanks for the links, I take a closer look at that first. best regards, Markus