proposition to std.range: SortedRange.indexOf(value)

[Alexander Tankeev]

On 12/19/2012 08:19 PM, Andrei Alexandrescu wrote:

>> I find very useful and clean interface that provides SortedRange, but it
>> was disappointing that it have binarySearch to answer does it
>> .contains(value), but can't return the .indexOf(value). In my opinion it
>> should be part of the interface.

> What to return if there are several indexes for a value? That's why the
> more general lowerBound, upperBound, equalRange, and trisect are defined.

Ok, and what if value isn't in Range at all? How lowerBound, upperBound, 
equalRange can help in such case?

auto a = assumeSorted([ 0, 1, 2, 3, 4, 5, 10, 11, 12, 14 ]);
auto p = a.lowerBound(7);
assert(equal(p, [0, 1, 2, 3, 4, 5]))

Sure I can do .contains(value) and then index is 
.lowerBound(value).length but it's 2 searches where 1 could be enough.

And what if you need all indexes of equal elements? Then you should do 3 
searches where 1 could be enough.