A comparison between C++ and D

[bigsandwich via Digitalmars-d]

On Wednesday, 9 March 2016 at 22:05:28 UTC, Ola Fosheim Grøstad 
wrote:
> On Wednesday, 9 March 2016 at 20:41:35 UTC, bigsandwich wrote:
>> Right,  I used to this sort of thing in C++ prior to C++11.  I 
>> think not having an RAII wrapper for lambdas similar to 
>> std::function<> is an oversight for D, especially for people 
>> averse to GC.  That little bit of syntactic sugar makes a huge 
>> difference.
>
> std::function<> is a lot more than syntactic sugar, it is a 
> runtime-heavy construct. From 
> http://en.cppreference.com/w/cpp/utility/functional/function :
>
> «Class template std::function is a general-purpose polymorphic 
> function wrapper. Instances of std::function can store, copy, 
> and invoke any Callable target -- functions, lambda 
> expressions, bind expressions, or other function objects, as 
> well as pointers to member functions and pointers to data 
> members.»
>
> I don't think you want this...

Yes, I do.  std::function<> uses type erasure to store a 
"function".  If its small enough, its stored internally, 
otherwise it goes on the heap.  It uses RAII to manage the 
lifetime of the lambda.  D is using the GC for managing the 
lifetime.  D doesn't have a way of doing this without the GC.