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=-2.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM, MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,7f2ce8bda9cae4ab X-Google-Attributes: gid103376,public Path: controlnews3.google.com!news1.google.com!news.glorb.com!news.cs.univ-paris8.fr!univ-lyon1.fr!in2p3.fr!proxad.net!usenet-fr.net!enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail From: "Marius Amado Alves" Newsgroups: comp.lang.ada Subject: Re: "Must instantiate controlled types at library level." Why? Date: Mon, 17 May 2004 17:50:23 +0100 Organization: Cuivre, Argent, Or Message-ID: References: <1mbha09eg9amttqgidkj4j4efm0e81o55d@4ax.com> NNTP-Posting-Host: lovelace.ada-france.org Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Trace: melchior.cuivre.fr.eu.org 1084812620 16390 212.85.156.195 (17 May 2004 16:50:20 GMT) X-Complaints-To: usenet@melchior.cuivre.fr.eu.org NNTP-Posting-Date: Mon, 17 May 2004 16:50:20 +0000 (UTC) To: Return-Path: X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-OriginalArrivalTime: 17 May 2004 16:50:08.0908 (UTC) FILETIME=[03432CC0:01C43C2F] X-Virus-Scanned: by amavisd-new-20030616-p7 (Debian) at ada-france.org X-BeenThere: comp.lang.ada@ada-france.org X-Mailman-Version: 2.1.4 Precedence: list List-Id: "Gateway to the comp.lang.ada Usenet newsgroup" List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Xref: controlnews3.google.com comp.lang.ada:643 Date: 2004-05-17T17:50:23+01:00 I associate first-class citizenship with being an object. For example, in most languages (including Ada), types are NOT first-class citizens. In languages with a MOP (Meta-Object Protocol), e.g. Smalltalk, types ARE first-class citizens. In most prototype-based languages (e.g. Io) everything is an object. Being an object meaning loosely that it can be passed around, inspected, changed, copied, read, written, put in a container etc., especially at run time. For example, in Ada, every now and then a you need to print the component names of a record. You cannot extract them programmatically, because they aren't first class.