Rather neat way of doing multiple return values

[Chris Nicholson-Sauls]

kris wrote:
> Tom S wrote:
>> Downs wrote:
>>
>>> Here's a (imnsho) rather neat implementation of multiple return 
>>> values from functions.
>>>
>>> (...)
>>> Have fun! :D
>>
>>
>> Hehehe nice :) Here's my version:
>>
>>
>> ---
>>
>> import std.stdio;
>> import std.bind;
>>
>>
>>
>> struct PtrTuple(P, V) {
>>     P ptrs;
>>
>>     void opAssign(V v) {
>>         foreach (i, x; v.value) {
>>             *ptrs.value[i] = x;
>>         }
>>     }
>> }
>>
>>
>>
>> PtrTuple!(PointerTuple!(Tuple!(T)), Tuple!(T)) tup(T ...)(inout T t) {
>>     PtrTuple!(PointerTuple!(Tuple!(T)), Tuple!(T)) ptrs;
>>                    foreach (i, dummy_; t) {
>>         ptrs.ptrs.value[i] = &t[i];
>>     }
>>
>>     return ptrs;
>> }
>>
>>
>> Tuple!(int, float, char) someFunc(int i) {
>>     return tuple(i, 0.1f * i, cast(char)i);
>> }
>>
>>
>>
>> void main() {
>>     int a;
>>     float b;
>>     char c;
>>
>>     tup(a, b, c) = someFunc(55);
>>
>>     writefln("a = %s", a);
>>     writefln("b = %s", b);
>>     writefln("c = %s", c);
>> }
>>
>> ---
>>
>> Maybe Phobos could use such a utility, as it (apparently) gets 
>> reimplemented numerous times ?
>>
>>
>> -- 
>> Tomasz Stachowiak
> 
> 
> Cool, but it's worth pointing out that this is probably Latin to most 
> people :)

Not I; in fact, I'm loving it.  (Although I liked the PHP'ish use of list() for 
assignment.  I'm strange.)  Maybe we could evolve this toward a LambdaMOO/ColdC style 
scatter assignment.  Contrived ColdC example:

protected method ._cmd_viewCacheInfo {
   var width, depth, map, row;

   [width, depth, map] = cache_info(); // <- scatter
   .tell("Cache Width = ", width);
   .tell("Cache Depth = ", depth);
   .tell("Map: (Legend: i/I = Inactive, a/A = Active, I/A = Dity)");
   for row in (map) {
     .tell("  ", @row); // <- list spice, also available in scatter
   }
   .tell();
}

I can dream.  And this comes right up against it, just need a way to specify a catch-all 
at the end for trailing elements.

-- Chris Nicholson-Sauls