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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,47def5aa7b3182bd X-Google-Attributes: gid103376,public From: tmoran@bix.com (Tom Moran) Subject: Re: How to write TYPECASE in Ada 95? Date: 1999/02/18 Message-ID: <36cbb8b3.35099816@news.pacbell.net>#1/1 X-Deja-AN: 445608188 References: <79fct8$9k3$1@murdoch.acc.Virginia.EDU> <1103_918264881@DZOG-CHEN> <36cb2712.1390453@news.pacbell.net> X-Complaints-To: abuse@pacbell.net X-Trace: typhoon-sf.pbi.net 919320914 207.214.215.60 (Wed, 17 Feb 1999 22:55:14 PDT) Organization: SBC Internet Services NNTP-Posting-Date: Wed, 17 Feb 1999 22:55:14 PDT Newsgroups: comp.lang.ada Date: 1999-02-18T00:00:00+00:00 List-Id: >If you want to extend a type with arbitrary behavior, you could take a >look at using the Visitor pattern. Ada implementations of this pattern >are available at the ACM patterns archive. > Am I looking at the right place? I see >package body Equipment.Pricing is > function Get_Total_Price > (Equipment : Root_Equipment'Class) return Dollars is > begin > if Equipment in Floppy_Disk then > declare > Disk : Floppy_Disk renames Floppy_Disk (Equipment); > begin > return Get_Price_Of_Floppy_Disk (Disk); > end; > elsif Equipment in Hard_Disk then > declare > Disk : Hard_Disk renames Hard_Disk (Equipment); > begin > return Get_Price_Of_Hard_Disk (Disk); > end; which surely looks pretty similar to > procedure Serve_Fruit(Dish : in Fruit'class) is > begin > if Dish in Apple'class then Serve(Apple(Dish)); > ... > elsif Dish in Watermelon'class then Serve(Watermelon(Dish));