Re: [boost] Report from Berlin C++ Standards Committee meeting

From: Doug Gregor (dgregor_at_[hidden])
Date: 2006-04-10 13:29:53

On Apr 10, 2006, at 11:50 AM, Robert Ramey wrote:
> On the other hand - I don't see the motivation for including concepts
> in the core language.  Haven't we been able to implement concept
> checking with the current facilities of the library?  It seems to  
> me that
> the main problem these days with the C++ language these days is that
> its too hard to write a correct compiler for it.  Making the core
> language fancier will only make this problem worse.

Imagine a world where the compiler type-checks your templates when  
you define them, so that no type errors slip past until instantiation  
time. A world where misuse of template libraries results in 2-line  
error message instead of a 2-megabyte error message, where user  
errors are diagnosed as user errors and implementor errors are  
diagnosed as implementor errors. Imagine throwing away all of that  
imprecise concept documentation we use, replacing it with precise  
concept definitions checked by the compiler. Imagine composing  
generic libraries together without writing a single adaptor class,  
where it doesn't matter if I call it "x.size()", "size(x)", or "length 
(x)".  And do it all without breaking existing code.

Concepts will drastically improve our ability to write solid generic  
libraries in C++. When we've improved our compiler and introductory  
material, we'll announce the next release of ConceptGCC. I strongly  
encourage everyone interested in library design to give it a try.

        Doug