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-Thread: 103376,7728b533f7ab5fb6 X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "(see below)" Newsgroups: comp.lang.ada Subject: Re: Avoiding side effects Date: Wed, 08 Oct 2008 16:32:16 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Trace: individual.net gRaHBsjg+Tfaj3YND+O24QNxYYCxdsbMkU5EOnTeoEl7909hpw Cancel-Lock: sha1:bTkqJ5smCj6gE3n3LCvNN7Sv/vg= User-Agent: Microsoft-Entourage/12.12.0.080729 Thread-Topic: Avoiding side effects Thread-Index: AckpWwr+ij0t51BuTkeyQwB5EbqRYQ== Xref: g2news1.google.com comp.lang.ada:2279 Date: 2008-10-08T16:32:16+01:00 List-Id: On 08/10/2008 06:16, in article u1vyrbra1.fsf@no.email.thanks.invalid, "Anders Wirzenius" wrote: > "(see below)" writes: > >> On 07/10/2008 15:47, in article uprmc4g3i.fsf@no.email.thanks.invalid, >> "Anders Wirzenius" wrote: >> >>> "(see below)" writes: >>> >>>> On 07/10/2008 12:08, in article wvbrfxn8hdc7.fsf@sun.com, "Ole-Hjalmar >>>> Kristensen" wrote: >>>> >>>>> Yes, I think any program which use a read/write interface to a file >>>>> will have side effects in that sense. The only way I can think of for >>>>> avoiding this would be to mmap the whole file, then it will appear as >>>>> an array of bytes. >>>> >>>> Why would stepping through an array not be thought a "side" effect? >>> >>> A function that returns the row of that array and only that >>> would perhaps be a function without side effects. The information >>> in that row can be fetched when needed. >> >> A function that always returns the same row of an array would be of little >> use, I should think. > > I have a feeling that the function can be programmed so that it returns > different row (numbers, or pointers in that array) depending on > the content of the rows in that array ;-) > > function Row_Number (Row_Number_In_Other_Array : in > Row_Number_Type) return Row_Number_Type is > -- Return a row number one higher than the row number of the row > -- identical to the row in the other array. > I think this beautifully illustrates the silliness that slavish adherence to dogma inevitably produces, in programming as in finance and politics. -- Bill Findlay chez blueyonder.co.uk