C tips (again)

[Andrei Alexandrescu]

bearophile wrote:
> Walter Bright:
>> Why couldn't you do the exact same thing in D?<
> 
> Those ctips show some tricks done with the preprocessor that I don't know yet how to do with D1, and there are some situations where in D I'd like to be able to locally disable array bound checks (this is doable in Delphi/FreePascal), like in the data array here:
> 
> typedef struct {
>     int size;
>     int capacity;
>     char data[0];
> } Mystring;

(untested)

struct Mystring {
     size_t size, capacity;
     char* pdata() { return cast(char*) (&this + 1); }
     char[] data() { return pdata()[0 .. size]; }
}

> But D is more or less a superset of C, so a D programmer may be able to implement all those things, as you say.
> The main point of my original post is that some of those ctips may be added as built-in idioms to D.

I've had a nice "blast from the past" feeling while skimming the 
document, but really it's more of a proof that with ingenuity and 
discipline a bear can be made to dance. I don't see how that stuff could 
help D any more than a coconut and two straws could help a radar receiver.

I have been mightily disappointed (essentially my respect for the author 
has crashed into the ground) when I saw that the entire optimization 
example, although clearly a lot of time and effort has been put into it, 
had absolutely no numbers whatsoever.

> Regarding possible things to be added to D: recently I have heard that some people is thinking about creating a small C compiler that supports some nonstadard low-level features, to be used to compile the future Linux kernel:
> http://lkml.org/lkml/2009/4/22/78
> If such project goes on, then it may show other things that may be useful in D if D wants to be fit to write kernels too.

IMHO all D needs for writing kernel-grade code is a way to code cleanly 
without the GC.


Andrei