Hi,
I recently came across the following code:
http://wiki.dlang.org/Higher_Order_Range_Pattern
I can't understand why the properties and methods of the
structure are called in the correct order.
Why are the property `back()` and the method `popBack()` are not
called even once?
In general, please explain how it all works.
```
import std.stdio, std.range;
struct Retro(Range)
{
@property
{
auto ref front() { debug writeln("back"); return
range_.back; }
auto ref back() { debug writeln("front"); return
range_.front; }
bool empty() { debug writeln("empty"); return
range_.empty; }
}
void popFront() { debug writeln("popBack"); range_.popBack();
}
void popBack() { debug writeln("popFront");
range_.popFront(); }
Range range_;
}
auto retro(Range)(Range range)
{
return Retro!Range(range);
}
void main()
{
import std.algorithm;
auto arr = [1, 2, 3, 4, 5];
assert(equal(retro(arr), [5, 4, 3, 2, 1]));
}
```
http://rextester.com/FMPGS76502
