From: Michael Edgar <adgar@...>
Date: 2011-07-18T15:05:35+09:00
Subject: [ruby-core:38157] Re: [Ruby 1.9 - Feature #4766] Range#bsearch

On Jul 18, 2011, at 1:30 AM, Yusuke ENDOH wrote:

> I agree that it seems neat, but it is ambiguous to me how it works
> concretely.  What do you expect the following code outputs?

I see now my misunderstanding; the "minimum value" heuristic
exists not to provide additional utility, but merely to direct tie-breaking
in the binary search in a consistent manner.

My proposed bsearch_matches would clearly need to know which
direction to break ties before it commenced (perhaps a 1/0/-1
argument), which starts to limit its usefulness.  While I personally
would prefer this as a base implementation for several methods to
bsearch with inverted block condition or "break" in the block,
I can't honestly say my idea would be worth it for a first implementation.

It does still irk me that the general name "bsearch" would have the
minimum-tie-breaking built-in, without that being reflected in the
name or an argument.  The additional behavior may surprise users.

Michael Edgar
adgar@carboni.ca
http://carboni.ca/