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!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Ada.Strings.Unbounded vs Ada.Containers.Indefinite_Holders Date: Sat, 23 Sep 2017 10:09:55 +0200 Organization: Aioe.org NNTP Server Message-ID: References: NNTP-Posting-Host: MajGvm9MbNtGBKE7r8NgYA.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 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.8.2 Xref: news.eternal-september.org comp.lang.ada:48205 Date: 2017-09-23T10:09:55+02:00 List-Id: On 2017-09-23 00:15, Victor Porton wrote: > Simon Wright wrote: > >> Victor Porton writes: >> >>> What is 2.5(6)? There is no (6) in RM 2.5. >> >> 2.6(6): >> >> A null string literal is a string_literal with no string_elements >> between the quotation marks. > > In my opinion, it would be better to change RM phrasing from "null string" > to "empty string", because in some other languages (notably C) NULL means > something other. It is just confusing. The adjective null and the noun null are distinct parts of speech. C's noun null is an abbreviation of null pointer. If pointers can be null so strings can. Wouldn't it be silly to change, say, mathematical group theory with its null group elements because C (and Ada too) have null pointers called nulls? BTW, empty is string is indeed a null element for the concatenation operation &: forall X in String X & "" = X So, using the null adjective is absolutely justified. A null string is a bit more than just empty string. (:-)) -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de