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=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,1de1981df403322c X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-11-11 02:18:47 PST Path: archiver1.google.com!postnews1.google.com!not-for-mail From: martin.dowie@btopenworld.com (Martin Dowie) Newsgroups: comp.lang.ada Subject: Re: New limited range type? Date: 11 Nov 2003 02:18:47 -0800 Organization: http://groups.google.com Message-ID: References: <20619edc.0311071005.15e6b9a8@posting.google.com> NNTP-Posting-Host: 20.138.254.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1068545927 21335 127.0.0.1 (11 Nov 2003 10:18:47 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Tue, 11 Nov 2003 10:18:47 +0000 (UTC) Xref: archiver1.google.com comp.lang.ada:2331 Date: 2003-11-11T02:18:47-08:00 List-Id: > > How about: > > > > function S'Limit (X:... > > Or maybe Limit_to_Bounds? Wordy, but clearer. I still prefer 'Limit ;-) I don't think the extra words add much, if I saw "'Limit" and I'd never seen it before I'd simply look up the RM. There are loads of existing attribute names that could be wordier to be made clearer... > > While that's good technique, I presume your NOT saying that the RM would > > require this? > > I thinkj it would be necessary to adopt this approach, since the base range > required cannot be guessed. I think the neatest solution is to require a > named type with this range to be declared, and then subtypes with the > required limited ranges to be declared and used to indicate the bounds of > the operation. No it isn't - like I said in my original post, it can all be done with generics as it is - it's just a pain to have to keep including new instances when it could easily be part of the language - see example at the end of this reply. > > Also, why not allow it for any scalar type? > > Yes, I think you're right. Shall I send a proposal to ada-comment? Ok :-) ----------------------------- -- generic_limit_fixed.ads -- ----------------------------- generic type T is delta <>; function Generic_Limit_Fixed (V : T'Base) return T; ----------------------------- -- generic_limit_fixed.adb -- ----------------------------- function Generic_Limit_Fixed (V : T'Base) return T is begin if V < T'First then return T'First; elsif V > T'Last then return T'Last; else return V; end if; end Generic_Limit_Fixed; ----------------------------- -- generic_limit_float.ads -- ----------------------------- generic type T is digits <>; function Generic_Limit_Float (V : T'Base) return T; ----------------------------- -- generic_limit_float.adb -- ----------------------------- function Generic_Limit_Float (V : T'Base) return T is begin if V < T'First then return T'First; elsif V > T'Last then return T'Last; else return V; end if; end Generic_Limit_Float; --------------- -- tests.ads -- --------------- with Generic_Limit_Fixed; with Generic_Limit_Float; package Tests is type Safe_Fixed_Degrees is delta 0.125 range -180.00 .. 180.0; function Limit is new Generic_Limit_Fixed (Safe_Fixed_Degrees); type Safe_Float_Degrees is digits 6 range -180.00 .. 180.0; function Limit is new Generic_Limit_Float (Safe_Float_Degrees); end Tests; -------------- -- test.adb -- -------------- with Ada.Text_IO; use Ada.Text_IO; with Tests; use Tests; procedure Test is procedure Test_Float is A, B, C : Safe_Float_Degrees; begin B := 170.0; C := 50.0; A := Limit (B + C); Put_Line ("A =" & Safe_Float_Degrees'Image (A)); end Test_Float; procedure Test_Fixed is A, B, C : Safe_Fixed_Degrees; begin B := 170.0; C := 50.0; A := Limit (B + C); Put_Line ("A =" & Safe_Fixed_Degrees'Image (A)); end Test_Fixed; begin Test_Float; Test_Fixed; end Test;