System programming in D (Was: The God Language)

[Timon Gehr]

On 01/05/2012 12:54 AM, Manu wrote:
> On 5 January 2012 01:40, Timon Gehr <timon.gehr at gmx.ch
> <mailto:timon.gehr at gmx.ch>> wrote:
>
>     On 01/05/2012 12:26 AM, Manu wrote:
>
>         You just missed a big discussion on IRC about this, where I
>         think I made
>         some fair points that people actually agreed with.
>
>             On 1/4/2012 10:53 AM, Manu wrote:
>
>                 Oh, and virtual-by-default... completely unacceptable for a
>                 systems language.
>                   most functions are NOT virtual, and finding the
>         false-virtuals
>                 while
>                 optimising will be extremely tedious and time consuming.
>
>
>             The only reason to use classes in D is for polymorphic
>         behavior -
>             and that means
>             virtual functions. Even so, a class member function will be
>         called
>             directly if
>             it is private or marked as 'final'.
>
>
>         Is this true? Surely the REAL reason to use classes is to
>         allocate using
>         the GC?
>
>
>     You can allocate any type using the GC.
>
>         Aren't struct's allocated on the stack, and passed to functions by
>         value? Do I need to start using the ref keyword to use GC
>         allocated structs?
>
>
>     No.
>
>             An easy way to find functions that are not overridden (what you
>             called false virtuals) is to add:
>
>                final:
>
>             at the top of your class definition. The compiler will give you
>             errors for any functions that need to be virtual.
>
>             If you don't want polymorphic behavior, use structs instead.
>         Struct
>             member
>             functions are never virtual.
>
>
>         I have never written a class in any language where the ratio of
>         virtual
>         to non-virtual functions is more than 1:10 or so... requiring
>         that one
>         explicitly declared the vastly more common case seems crazy.
>
>
>     Are you sure that is the case?
>     In my code, most class member functions are true virtual.
>
>
> Here's one I'm working on right now (C++).
> Base class for a UI system, surely one of the most heavily polymorphic
> types of code one can imagine.

Apparently that is not true.

>
> Count the virtuals... http://pastebin.com/dLUVvFsL

9/~65 approx 1:6.