On Saturday, 22 December 2012 at 02:58:16 UTC, Timon Gehr wrote:
On 12/21/2012 06:01 PM, monarch_dodra wrote:
There are a lot of algorithms in std.algorithm that operate on
"foo(Range, Needles...)(Range range, Needles needles)".
Needles can be anything, in particular, either an "element" or
a "range".
The thing is that every now and then, you want to save the
entirety of
(the ranges) inside needles. EG, I want to be able to write:
foo(range, needles.saveAll);
I'm having trouble. I did two iterations:
//----
auto saveAll(Ranges...)(Ranges ranges) @property
{
auto ret = ranges;
foreach (Index, Type; Ranges)
static if (isForwardRange!Type)
ret[Index] = ranges[Index];
return ret;
}
//----
This doesn't work, because: Error: functions cannot return a
tuple
So that's that.
...
Use a phobos tuple?
return tuple(ret)
The caller can use .expand.
Victory! It works that way!
//----
auto saveAll(Stuff...)(Stuff stuff)
{
Stuff ret = stuff;
foreach(ref v; ret)
++v;
return tuple(ret);
}
void foo(Stuff...)(Stuff stuff)
{
bar(stuff.saveAll().expand);
}
void bar(Stuff...)(Stuff stuff)
{
foreach (v; stuff)
v.writeln();
}
void main()
{
foo(1, 2, 3);
}
//----
The only limitation is that I can't declare it as a property. I
get:
main.d(11): Error: properties can only have zero, one, or two
parameter
I'd say that a bug (or at least, an unnecessary restriction), but
I can live with it.
Thankyou!
