I understand that `removeKey` works only with the comparator "a < b":
http://dlang.org/phobos/std_container_rbtree.html#.RedBlackTree.removeKey
>Removes elements from the container that are equal to the given values according to the less comparator.

How do I remove the key from the `redBlackTree` with comparator "a <= b" ?

auto rbt = redBlackTree!("a <= b", int)(1, 2, 3, 4, 5, 6, 7);
rbt.removeKey(6);

foreach (key; rbt)
    write(key);
// prints 1234567

On Sunday, 7 June 2015 at 18:42:58 UTC, Dennis Ritchie wrote:
> How do I remove the key from the `redBlackTree` with comparator "a <= b" ?

Do not use '<=' as a comparison function with RedBlackTree. It doesn't meet the requirements.

Quoting the documentation [1]:
> Note that less should produce a strict ordering. That is, for two unequal elements a and b, less(a, b) == !less(b, a). less(a, a) should always equal false.

This doesn't hold for '<='.

On Sunday, 7 June 2015 at 18:50:47 UTC, anonymous wrote:
> On Sunday, 7 June 2015 at 18:42:58 UTC, Dennis Ritchie wrote:
>> How do I remove the key from the `redBlackTree` with comparator "a <= b" ?
>
> Do not use '<=' as a comparison function with RedBlackTree. It doesn't meet the requirements.
>
> Quoting the documentation [1]:
>> Note that less should produce a strict ordering. That is, for two unequal elements a and b, less(a, b) == !less(b, a). less(a, a) should always equal false.
>
> This doesn't hold for '<='.

OK. But I want to return a `upperBound` segment with the included `key`. It does not suit me:

auto rbt = redBlackTree!("a < b", int)(1, 2, 3, 4, 5);
writeln(rbt.upperBound(3)); // prints [4, 5]

I want it to be so:

auto rbt = redBlackTree!("a <= b", int)(1, 2, 3, 4, 5);
writeln(rbt.upperBound(3)); // prints [3, 4, 5]

How do I do with the comparator "a < b" ?

On Sunday, 7 June 2015 at 19:04:08 UTC, Dennis Ritchie wrote:
> OK. But I want to return a `upperBound` segment with the included `key`. It does not suit me:
>
> auto rbt = redBlackTree!("a < b", int)(1, 2, 3, 4, 5);
> writeln(rbt.upperBound(3)); // prints [4, 5]
>
> I want it to be so:
>
> auto rbt = redBlackTree!("a <= b", int)(1, 2, 3, 4, 5);
> writeln(rbt.upperBound(3)); // prints [3, 4, 5]
>
> How do I do with the comparator "a < b" ?

Use equalRange to get the elements that equal 3, too:
writeln(std.range.chain(rbt.equalRange(3), rbt.upperBound(3)));

On Sunday, 7 June 2015 at 19:11:25 UTC, anonymous wrote:
> On Sunday, 7 June 2015 at 19:04:08 UTC, Dennis Ritchie wrote:
>> auto rbt = redBlackTree!("a <= b", int)(1, 2, 3, 4, 5);
>> writeln(rbt.upperBound(3)); // prints [3, 4, 5]
>>
>> How do I do with the comparator "a < b" ?
>
> Use equalRange to get the elements that equal 3, too:
> writeln(std.range.chain(rbt.equalRange(3), rbt.upperBound(3)));

Thank you!

On Sunday, 7 June 2015 at 18:50:47 UTC, anonymous wrote:
> Do not use '<=' as a comparison function with RedBlackTree. It doesn't meet the requirements.
>
> Quoting the documentation [1]:
>> Note that less should produce a strict ordering. That is, for two unequal elements a and b, less(a, b) == !less(b, a). less(a, a) should always equal false.
>
> This doesn't hold for '<='.

Could we add a static check for this?

On 6/8/15 6:53 AM, "Per =?UTF-8?B?Tm9yZGzDtnci?= <per.nordlow@gmail.com>" wrote:
> On Sunday, 7 June 2015 at 18:50:47 UTC, anonymous wrote:
>> Do not use '<=' as a comparison function with RedBlackTree. It doesn't
>> meet the requirements.
>>
>> Quoting the documentation [1]:
>>> Note that less should produce a strict ordering. That is, for two
>>> unequal elements a and b, less(a, b) == !less(b, a). less(a, a)
>>> should always equal false.
>>
>> This doesn't hold for '<='.
>
> Could we add a static check for this?

How would a static check generate a and b generically?

-Steve