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: 103376,4c019ad9cc913bbe X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-09-19 13:33:16 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!sn-xit-03!sn-xit-06!sn-post-02!sn-post-01!supernews.com!corp.supernews.com!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: The Dreaded "Missing Subunits" Date: Thu, 19 Sep 2002 15:34:02 -0500 Organization: Posted via Supernews, http://www.supernews.com Message-ID: References: <1b585154.0209121449.ef12609@posting.google.com> <3D819EE7.3A69E5EB@praxis-cs.co.uk> X-Newsreader: Microsoft Outlook Express 4.72.3612.1700 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3719.2500 X-Complaints-To: abuse@supernews.com Xref: archiver1.google.com comp.lang.ada:29198 Date: 2002-09-19T15:34:02-05:00 List-Id: Robert A Duff wrote in message ... >Every time you tell the tool to re-analyze the world, it has to do this: >(1) Expand the wildcard(s), to see if there are any new files or any >files have been deleted. Then (2) check the timestamp on each source >file to see if it has been changed. Then it has to re-parse all the >files that have changed, or are new (and it has to forget about >information related to deleted files). This process is quite fast, even >for large programs. It's essentially what 'make' does when you say >'make main_program', or what 'gnatmake' does when told to build a >program. Careful! Don't assume that these steps are faster than just parsing the file. When we were (re)designing our make tool, we found that reading a timestamp took about the same amount of time as parsing 500 lines of a file (this was on MS-DOS/Windows 95, I think). Moreover, saving the gathered information on disk was complex enough that it cost the same as parsing another 1000 lines of a file. Not many Ada files are bigger than 1500 lines. So we don't even try to save information about source files; reparsing and rebuilding the information in memory is generally faster. This is essentially the basis of Xtreme Programming, after all: don't build something complex until you've proven that the simple version is too slow. (Just another piece of common sense that someone is making a lot of money selling to people without it.) Randy Brukardt