commonLength

[Tobias Pankrath via Digitalmars-d-learn]

> I just discovered that zip has StoppingPolicy so why does
>
> auto commonPrefixLength(R...)(R ranges) if (ranges.length == 2)
> {
>     import std.range: zip;
>     return zip!((a, b) => a[0] != b[1])(ranges);
> }
>
> unittest
> {
>     assert(commonPrefixLength([1, 2, 3, 10],
>                               [1, 2, 4, 10]) == 2);
> }
>

StoppingPolicy is not a template parameter, it is this one: 
http://dlang.org/phobos/std_range.html#.StoppingPolicy