Xref: utzoo comp.lang.misc:3823 comp.software-eng:2725 Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!mcsun!ukc!edcastle!lfcs!nick From: nick@lfcs.ed.ac.uk (Nick Rothwell) Newsgroups: comp.lang.misc,comp.software-eng Subject: Re: An Interesting View of "Strong" Vs. "Weak" Typing Keywords: typing, Ada, Lisp, definitions, evidence Message-ID: <1493@castle.ed.ac.uk> Date: 5 Jan 90 11:44:52 GMT References: <641@ajpo.sei.cmu.edu> Reply-To: nick@lfcs.ed.ac.uk (Nick Rothwell) Followup-To: comp.lang.misc Organization: LFCS Enya Admiration Society Lines: 34 In-reply-to: eberard@ajpo.sei.cmu.edu (Edward Berard) In article <641@ajpo.sei.cmu.edu>, eberard@ajpo (Edward Berard) writes: I would be interested in getting your reaction to the >following quotes from one of respondees: >> More accurately, run-time typing places the burden on the run-time >> system, whereas compile-time typing places the burden on the >> compiler *and* the programmer (who must provide explicit type ^^^^^^^^^^^^... >> declarations and obey them at all times during program >> development). This is false for a polymorphic type system. >> I would ask again what solid *experimental* >> evidence anyone has to show that compile-time typing actually >> results in programs more reliable than those possible with >> run-time typing, *in the presence of the requirements evolution >> that is present in any large, complex software project*. Do you mean "practical experience"? I wrote 8000 lines in ML, and hand-translated to 20000 lines of C, in 4 months, resulting in a reliable piece of software. I don't know how to quantify that in any objective way, though. I suggest that compile-time typing serves the same purpose as module interfaces: it lets you decide what you want different parts of a project to see, and what operations you want to provide (I'm thinking of a parameterised, abstract type system here). Nick. -- Nick Rothwell, Laboratory for Foundations of Computer Science, Edinburgh. nick@lfcs.ed.ac.uk !mcvax!ukc!lfcs!nick ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ "...all these moments... will be lost in time... like tears in rain."