Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!sample.eng.ohio-state.edu!purdue!haven!ni.umd.edu!uc780.umd.edu!cs450a03
From: cs450a03@uc780.umd.edu
Newsgroups: comp.lang.misc
Subject: RE: Run-time Type Errors in Smalltalk
Message-ID: <15APR91.20525963@uc780.umd.edu>
Date: 15 Apr 91 20:52:59 GMT
References: <1917@optima.cs.arizona.edu> <1991Apr15.234559.16293@comp.vuw.ac.nz>
Sender: usenet@ni.umd.edu (USENET News System)
Organization: The University of Maryland University College
Lines: 22

Brian Boutel writes:

>The claim that testing catches all errors is laughable. Errors show
>up in production code every day. Testing, as we tell first year
>students, does not demonstrate the absence of errors, only their
>presence.

By the same token, the claim that static typing catches all errors is
invalid.  And if a language _requires_ a significant amount of
programmer time to be spent micro-managing static type declarations,
it introduces the possibility for more errors -- errors which may not
be caught in testing.

>So what can be said about all the errors in the quoted C++ project
>that were not caught by testing and are still in the production code?
> 
>I'll tell you. They are not type errors.

No, they were not _static_ type errors.  You don't know if they'd be
caught by run-time type checking.

Raul Rockwell