Path: utzoo!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!usc!elroy.jpl.nasa.gov!decwrl!deccrl!news.crl.dec.com!shlump.nac.dec.com!engage!marx.enet.dec.com!grier From: grier@marx.enet.dec.com Newsgroups: comp.lang.misc Subject: Re: Dynamic typing (part 3) Message-ID: <1991Mar13.010946.4536@engage.enet.dec.com> Date: 13 Mar 91 01:09:46 GMT References: <602@optima.cs.arizona.edu> Sender: news@engage.enet.dec.com (USENET News System) Reply-To: grier@marx.enet.dec.com () Organization: Digital Equipment Corporation Lines: 48 In article , peter@ficc.ferranti.com (Peter da Silva) writes: |> In article <602@optima.cs.arizona.edu> gudeman@cs.arizona.edu (David |> Gudeman) writes: |> > Now people have actually come to believe, against all |> > evidence, that static typing is important for program reliability. |> |> No, they believe that dynamic typing imposes a certain unavoidable |> runtime |> overhead, and aren't willing to pay that cost. As computers get |> faster this |> becomes more of a moot point outside the frantic world of embedded |> controllers |> and videogames. |> Actually, reliability is exactly my argument. I think that in most cases, the static typing of an expression can be inferred, and thus the best instruction sequence be selected. (Going out on a limb here, but I've never been known to be timid in making statements or speculations.) My argument is for reliability in engineering of large software systems, where a type or operator change might produce an error embedded somewhere which cannot be determined statically (remember, there still *has* to be a case where the type inference logic can't determine the type of an expression, and thus has to assume the worst,) and might not be found for quite some time. If this is your favorite game, this might be annoying but not truly harmful. If this is a nuclear power plant or air traffic controller station, well, let's just hope it doesn't happen. I also claim agnostance(is that a real word?) on the utility of dynamic typing. Other than BASIC, I can't say I've ever used it to build any real software, and I'd be a lot happier to have a hard and fast notion of the type to which a reference/variable refers at any given point in the program text than to freely toss about dynamically typed variables. But I'm poisoned from learning FORTRAN and BASIC at a frightfully early age and I'm probably ruined for life in that respect. :-) -mjg ------------------------------------------------------------------------ I'm saying this, not Digital. Don't hold them responsibile for it! Michael J. Grier Digital Equipment Corporation (508) 496-8417 grier@leno.dec.com Stow, Mass, USA Mailstop OGO1-1/R6