improving the join function

[Andrei Alexandrescu]

On 10/13/10 14:03 CDT, Steven Schveighoffer wrote:
> On Mon, 11 Oct 2010 20:33:27 -0400, Andrei Alexandrescu
>> T[] join(T)(in T[][] items, T[] sep);
>
> This doesn't quite work if T is not a value type (actually, I think it
> does, but only because there are bugs in the compiler).

My focus in this discussion is not the const aspect, but point taken.

> Well, one could have a version of join that takes an output range. It
> would have to return the output range instead of the *result* of the
> output range. And in that case, the standard join which returns an array
> can be implemented:
>
> ElementType!R1[] join(R1 items, R2 sep) ...
> {
> return join(R1, R2, Appender!(ElementType!R1)).data;
> }

Yah, I had a similar idea:

void join(In1, In2, Out)(In1 items, In2 sep, Out target);

as an overload.

>> I also have a question from people who dislike Phobos. Was there a
>> point in the changes of signature above where you threw your hands
>> thinking, "do the darn string version already and cut all that crap!"?
>
> It's not a problem with phobos, it's a problem with documentation. There
> is a fundamental issue with documenting complex templates which makes
> function signatures very difficult to understand. The doc generator can
> and should simplify things, and I think at some point we should address
> this. In other words, it should be transformed into a form that's easy
> to see that it's the same as string[] join(string[][], string[]).

Good point. On the other hand, an overly simplified documentation might 
hinder a good deal of legit uses for advanced users. I wonder how to 
please everyone.


Andrei