x.sizeof vs typeid(x)

[Sergey Gromov]

What can I say.  I do not agree.  C++ committee is not the best 
exemplar.  Looking into implementation should be required to learn the 
details, not to understand what the hell is going on.  Creating the DSLs 
should be a privilege of scripting languages, that's what they are for, 
after all.

Tom S <h3r3tic at remove.mat.uni.torun.pl> wrote:
> Sergey Gromov wrote:
> > opIn has a distinct default semantics in the language.  It's 
> > "check if," not an "apply to."  The ability to overload is here to mimic 
> > the default semantics for non-ordinary types.  It's a bad practice IMO 
> > to completely change operator semantics.
> 
> Well then, the whole C++ committee is following bad practice as well, by 
> making << and >> work with streams. Following semantics is one thing - 
> sure. It's crucial when you're making your own Map container to support 
> it in exactly the same way as the built-in AAs do. But if you can make 
> your code more natural to write by abusing the operators a little - 
> opIn, operator<<, etc, then it's not a very bad practice IMHO. In fact, 
> anyone defining opMul for their matrix class/struct is breaking 
> semantics. The spec states that opMul is commutative.
> 
> 
> > That's exactly why a 
> > concatenation operator is added to D: to ensure that what you think is 
> > being done is actually what is done, at least conceptually.
> 
> Wrong. As far as I know, it was added because D was supposed to have 
> array operations, so you could say [1, 2] + [10, 10] and have [11, 12], 
> not the concatenation.
> 
> 
> > That's also the reason I didn't like the luabind library for C++. Here's 
> > a piece of C++ code:
> > 
> >     module(L)
> >     [
> >         def("greet", &greet)
> >     ];
> > 
> > What it does, God knows.
> 
> It doesn't really matter. Would you actually know without looking at the 
> implementation? It's easy to read, the language features used can be 
> figured out rather easily.
> What matters is that it's really easy to use. It's actually a very nice 
> example of a DSL (Domain Specific Language) within C++. Would you rather 
> write 4 times this much, in order just to have it look like the rest of 
> C++ code? Because then, there's the low level C API...

-- 
SnakE