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,c406e0c4a6eb74ed X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!news.glorb.com!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!feed2.news.rcn.net!rcn!feed3.news.rcn.net!not-for-mail Sender: jsa@rigel.goldenthreadtech.com Newsgroups: comp.lang.ada Subject: Re: ADA Popularity Discussion Request References: <49dc98cf.0408110556.18ae7df@posting.google.com> <6F2Yc.848$8d1.621@newsread2.news.pas.earthlink.net> <413e2fbd$0$30586$626a14ce@news.free.fr> From: jayessay Organization: Tangible Date: 08 Sep 2004 19:01:15 -0400 Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: DXC=YTUI6DT4Ha1dbCMLkBe9n40R]m=BkYWI7:6bU3OT9S9:9FlFRoa4Gh=^aM2i8keRm=`_FBVn?ZK1< X-Complaints-To: abuse@rcn.com Xref: g2news1.google.com comp.lang.ada:3512 Date: 2004-09-08T19:01:15-04:00 List-Id: "Richard Riehle" writes: > "jayessay" wrote in message > news:m3n000bv64.fsf@rigel.goldenthreadtech.com... > > > Yes, you are correct. Dynamic typing is every bit (and in some ways > > more) strong as static typing. > > > There are many kinds of strength. The kind I believe that people intend in this context involves the notions of "consistency" and adherence to various "constraints". > I am wondering whether > you are intellectually honest enough to state the weaknesses > as well as the strengths of the Lisp approach. Presumably you mean ^^^^ "dynamic typing" here as that is the context of this subsubthread (which would include many others than Lisp). The weakness in this context is obvious: if you use a _formal_ static type system and your problem can be stated completely in it, you can indeed _prove_ with automated methods various useful properties from the source code. > There are, admittedly, many benefits from the Lisp dynamic > typing model, under some circumstances. There are many > disadvantages, under other circumstances, to the static > typing model of Ada, C++, and others. Since Ada is more > type safe than those others, those disadvantages sometimes > are more pronounced. However, there are definite benefits > to the static typing model, when it is used intelligently, and > those often outweigh the disadvantages. [Aside: I believe that formal type systems like those of Haskell, OCAML, et.al. are much more potent than the informal ones of Ada, C++, Java, etc. Would you agree with this? I ask because one would think that a static typist would want to use the best version of that kind of system available which is not what is available in Ada/Eiffel/... so there must be some other more important reason for using these than the typing they provide] > Where do you see the disadvantages of the Lisp dynamic > typing approach? Compared to Hindley-Milner type systems (as in Haskell, etc.), using type inference, with dynamic typing you lose the ability to prove certain interesting invariants and other properties automatically from the source code. You can augment some dynamic systems with static analysis which can get you some of this (a lot?) of this. But, frankly, I don't know enough about these efforts as I haven't looked at them in enough detail. /Jon -- 'j' - a n t h o n y at romeo/charley/november com