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=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD, FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,243dc2fb696a49cd X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!postnews1.google.com!not-for-mail From: kevin.cline@gmail.com (Kevin Cline) Newsgroups: comp.lang.ada Subject: Re: Ada Popularity: Comparison of Ada/Charles with C++ STL (and Perl) Date: 26 Sep 2004 00:13:51 -0700 Organization: http://groups.google.com Message-ID: References: <41547dae$0$91007$39cecf19@news.twtelecom.net> NNTP-Posting-Host: 24.219.97.214 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1096182831 1509 127.0.0.1 (26 Sep 2004 07:13:51 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sun, 26 Sep 2004 07:13:51 +0000 (UTC) Xref: g2news1.google.com comp.lang.ada:4195 Date: 2004-09-26T00:13:51-07:00 List-Id: "Matthew Heaney" wrote in message news:<41547dae$0$91007$39cecf19@news.twtelecom.net>... > "Kevin Cline" wrote in message > news:e749549b.0409240828.53001e66@posting.google.com... > > > > In C++ you can write ++concordance[word] because of two features > > present in C++ that are missing in Ada. C++ allows the indexing > > operator [] to be overridden, so that concordance[key] can be assigned > > a meaning. Also, C++ has reference types, so that concordance[key] > > can return a modifiable reference to the value, which can be > > incremented. Together, these functions allow user-defined types in > > C++ to be as convenient to use as the built-in array type. > > Note that (as Randy alluded to) there's still a chance the ARG will add > something like reference types to Ada. It would be declared something like: > > function Update_Element > (Container : in Map; > Key : in Key_Type) return access Element_Type; > > Then you could say: > > Update_Element (M, K).all := 42; > > In our wordcount example you'd have to say: > > declare > N : Natural renames Update_Element (M, K).all; > begin > N := N + 1; > end; > > Note that it would possible to get the automatic insertion behavior too, by > passing the container as an access parameter: > > function Update_Element > (Container : access Map; > Key : in Key_Type) return access Element_Type; > > and then say: > > declare > N : Natural renames Update_Element (M'Access, K).all; > begin > N := N + 1; > end; One of the most frustrating things I found in Ada programming was the inability to make user-defined types work like the built-in types. Given A: array (1..10) of integer; then the expression A(5) is a modifiable reference to the fifth element of A. After experience with C++ it was amazingly frustrating to learn that there was no way I could define My_Container so that I could write: C: My_Container ; C(5) := 7;