Poll: Primary D version

[Walter Bright]

Robert Clipsham wrote:
> On 22/05/10 17:42, Andrei Alexandrescu wrote:
>>> - Interfacing to C libraries is now overly complex thanks to const
>>> correctness. After updating all the function signatures I found phobos
>>> was completely lacking the functions to convert between C and D strings
>>> of varying constness or with different encodings (char/wchar/dchar).. I
>>> ended up writing my own functions
>>
>> Could you please give more detail on that? There should be essentially
>> no problem with using C-style strings with D regardless of constness.
> 
> extern(C)void someFunc(char*);
> 
> There is no function in phobos which will allow me to call this function 
> using a D string, toStringz() gives:
> 
> test.d(4): Error: function test.someFunc (char*) is not callable using 
> argument types (const(char)*)
> 
> Unless I cast away const, which isn't pretty if you've got a lot of 
> these functions, unless you write a wrapper for each one (my current 
> hack). to!() doesn't support it at all, and I can't find another method 
> in phobos for it.

What's necessary is to decide if someFunc changes the string data or not. If it 
does not, then it should be prototyped as:

     extern (C) void someFunc(const char *);

If it does, then the char* is the correct declaration, and an immutable string 
should not be passed to it.