[#67346] Future of test suites for Ruby — Charles Oliver Nutter <headius@...>

I'll try to be brief so we can discuss all this. tl;dr: RubySpec is

19 messages 2015/01/05

[ruby-core:67530] [ruby-trunk - Feature #10730] Implement Array#bsearch_index

From: mame@...
Date: 2015-01-12 08:43:50 UTC
List: ruby-core #67530
Issue #10730 has been updated by Yusuke Endoh.


You may want to use Range#bsearch for the case.

i =3D (0...ary.size).bsearch {|i| predicate(ary[i]) }

--=20
Yusuke Endoh <[email protected]>

----------------------------------------
Feature #10730: Implement Array#bsearch_index
https://bugs.ruby-lang.org/issues/10730#change-50944

* Author: Radan Skori=C4=87
* Status: Open
* Priority: Normal
* Assignee:=20
----------------------------------------

We currently have Array#bsearch but no Array#bsearch_index and to me it see=
ms that violates the principle of least surprise, especially when we consid=
er the other combinations of existing methods that find either an element o=
r it=E2=80=99s index.

For example: the method would be very useful when needing to slice out a pa=
rt of a sorted array. It would allow very quick location of the indices of =
the beginning and end of the segment.

A quick google of =E2=80=9Cruby bsearch_index=E2=80=9D reveals that I am no=
t the only one that needed and expected that function to exist:

http://stackoverflow.com/questions/23481725/using-bsearch-to-find-index-for=
-inserting-new-element-into-sorted-array
http://stackoverflow.com/questions/8672472/is-there-a-built-in-binary-searc=
h-in-ruby
https://github.com/tyler/binary_search#usage

The very good thing is that we can get that method almost for free since th=
e current implementation of bsearch internally finds the index and then loo=
ks up the actual element.

I have opened a PR on the github mirror that adds bsearch_index in what see=
ms to me the simplest way possible: https://github.com/ruby/ruby/pull/813 .=
=20
I changed the bsearch implementation into bsearch_index and based the bsear=
ch on it.=20
Please Note: The diff is deceptively large, if you look carefully you will =
notice that the change is actually small and the actual binary search algor=
ithm remained completely intact.=20

I have kept the behaviour documentation on bsearch and simply referenced it=
 from bsearch_index to minimize the documentation changes.



--=20
https://bugs.ruby-lang.org/

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