[phobos] Improvement of stream

[Ellery Newcomer]

On 07/05/2010 10:49 AM, Andrei Alexandrescu wrote:
> Good point. With ByChunk you only get to set the size once at 
> construction time. A natural extension of that would be to define a 
> property bufferSize that you can assign before calling popFront. That 
> would allow code like:
>
> inp.bufferSize = 4;
> inp.popFront();
> process(inp.front);
> inp.bufferSize = 100;
> inp.popFront();
> process(inp.front);
>
> I reckon that just calling read() with different lengths is a bit more 
> appealing. Also if you need to save the data you need to call 
> inp.front.dup which makes for an extra copy. The question is how often 
> you need to do all that versus just getting whatever data is available.

Well, most of my D IO experience has been with binary files where you're 
trying to get out fields of specific byte length and put them in 
dedicated structures. Currently, I read the entire file (if phobos had a 
standard InputStream interface thing I wouldn't be limited to files) 
into an array and work with that. But that's kind of a horrid situation. 
Note that std.zip is in the same boat.

The other thing is that extra copy. Personally, I'd rather the user 
provide the buffer.

Also, I currently use an ad-hoc InputStream interface whose read 
signature is

ubyte[] read(ubyte[] buffer);

which returns the slice of the buffer which was read in.

Do you have any opinion of this signature vs. the traditional signature?

> For wrapping structs in general, I hope we could have a more general 
> version similar to BlackHole and WhiteHole - automatic wrapping. 
> Consider:
>
> struct A {
>     this(int);
>     void foo();
>     int bar(string);
> }
>
> alias Classify!A ClassA;
>
> ClassA is as if somebody sat down and wrote the following class by hand:
>
> class ClassA {
>     private A payload;
>     this(int x) { payload = A(x); }
>     void foo() { return payload.foo(); }
>     int bar(string x) { return payload.bar(x); }
> }
>
> Things get more complicated with functions that receive or return type 
> A, properties, qualifiers etc. I think Classify would be an excellent 
> test of D's introspection capabilities, in addition to being useful in 
> practice.

That would be sweet

>
>
> Andrei