Does D have too many features?

[Jonathan M Davis]

On Sunday, May 06, 2012 21:18:38 foobar wrote:
> On Thursday, 3 May 2012 at 22:57:02 UTC, Walter Bright wrote:
> > On 5/3/2012 8:13 AM, Don Clugston wrote:
> >> Well, they are also used in druntime, in core.stdc.math
> >> BTW I *hate* that module, I don't know why it exists. Even
> >> worse, it seems to be
> >> growing -- people are adding more things to it.
> > 
> > It's there simply because all the Standard C headers should be
> > represented. It should not get anything that is not in Standard
> > C. Ditto for all the other stuff in core.stdc.
> > 
> > It's there to make converting C code to D code easier.
> 
> This argument comes up every once in a while even though AFAIK it
> is *not* a goal of D and never has been!
> D does not and *should not* strive to be source compatible with
> C. We already have C++ for that and it is a horrible idea.
> D can link with C which allows to use pre-existing C code. we
> should *not* encourage converting C code to D code at all. Either
> just link the C code or use D idiomatic code.

Then you misunderstand. One of the tenets that D holds to is that any C/C++ 
code either compiles as valid D code with identical semantics, or it doesn't 
compile as D code (there are a few minor exceptions - such as static arrays 
being passed by value - but not many). This means that we can break 
compatibility with C/C++ and do our own thing for a lot of stuff but that we 
can't just redefine what stuff does such that it would silently break code when 
it's ported from C/C++ to D.

That approach is _very_ different from C++'s approach where valid C code pretty 
much _always_ compiles identically in C++ (the fact that C++ added keywords 
being the only exception that I can think of at the moment), but that doesn't 
mean that we don't care about code portability from C/C++ to D. There's a huge 
difference between designing a language such that porting code to it from 
another language isn't error-prone and making the new language source 
compatibile. D does the former. C++ does the latter.

Being able to port code from C/C++ to D without having to worry about silent 
breakage _is_ one of D's goals.

- Jonathan M Davis