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[Caml-list] Q: safe language
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Date: | 2002-08-30 (15:56) |
From: | Vitaly Lugovsky <vsl@o...> |
Subject: | Re: [Caml-list] Q: safe language |
On 30 Aug 2002, David Frese wrote: > > > > (cadr '(1)) > > > > > > This shows that Lisp is safe, because it results in an error, and does > > > not return some value from out of nowhere (or does it). > > > > No. In this place program may be expecting some structure, which can > > contain NIL. There is no other way in lisp to define structures - so, any > > code accepting lists will accept any alien structure. Is is type safety? > > If you are refering to the fact, that the expression above returns NIL, > then yes, this is no type-safety, and a very bad thing - I did not know > that. It depends on the Lisp implementation. But, you can find a lot of "unsafe" examples with correct behavior: e.g. 3-d vector passed as 2-d vector, and lisp function working with structures using only cars and cdrs will not fail with it. > > No way! Dynamically typed languages can't be safe. > > I don't think this is a problem of dynamic or static typing, but a mad > behaviour of Lisp. With polymorphism and dymanic typing the programm may not fail at the point where wrong type was passed - and this is "unsafe" behaviour (this is where I have an ugly headache with Java). Statically typed language will not allow potentially unsafe function calls. ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners