From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Trait based containers
Date: Mon, 7 May 2018 09:14:22 +0200
Organization: Aioe.org NNTP Server
Message-ID: <pcoucb$1bvj$1@gioia.aioe.org>
References: <619088663.547202536.622332.laguest-archeia.com@nntp.aioe.org>
 <3de7cff3-9cfa-44bc-b837-5048bd813802@googlegroups.com>
 <fa962e1b-eaa1-416f-886f-0dcb0d4e359f@googlegroups.com>
NNTP-Posting-Host: MyFhHs417jM9AgzRpXn7yg.user.gioia.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Complaints-To: abuse@aioe.org
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.7.0
X-Notice: Filtered by postfilter v. 0.8.3
Content-Language: en-US
Xref: reader02.eternal-september.org comp.lang.ada:52063
Date: 2018-05-07T09:14:22+02:00
List-Id: <comp.lang.ada>

On 07/05/2018 09:02, briot.emmanuel@gmail.com wrote:

> I prefer to return a key in the "for..of" loop case, because with a map you
> can always go from key->element. The opposite might not  be true.

The main purpose of iteration is not to use keys and thus to avoid to 
the overhead of key-to-element mapping and, possibly, the volatility of 
keys.

Actually in most cases there should no iterators at all but an array 
view of the container instead. Iterators is a necessary evil of 
half-containers like lists, graphs etc.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de