"Strong typing vs. strong testing"

RG rNOSPAMon at flownet.com
Thu Sep 30 18:32:08 CEST 2010


In article <slrnia9cpd.2uqe.usenet-nospam at guild.seebs.net>,
 Seebs <usenet-nospam at seebs.net> wrote:

> On 2010-09-30, Lie Ryan <lie.1296 at gmail.com> wrote:
> > On 09/30/10 16:09, TheFlyingDutchman wrote:
> >> Dynamic typed languages like Python fail in this case on "Never blows
> >> up".
> 
> > How do you define "Never blows up"?
> 
> I would say "blow up" would be "raise an exception".
> 
> > Personally, I'd consider maximum(8589934592, 1) returning 1 as a blow
> > up, and of the worst kind since it passes silently.
> 
> So run your compiler with a decent set of warning levels, and watch as
> you are magically warned that you're passing an object of the wrong type.

My code compiles with no warnings under gcc -Wall.

> On any given system, one or the other is true:
> 
> 1.  The constant 8589934592 is of type int, and the function will
> "work" -- will give that result.
> 2.  The constant is not of type int, and the compiler will warn you about
> this if you ask.

It would be nice if this were true, but my example clearly demonstrates 
that it is not.  And if your response is to say that I should have used 
lint, then my response to that will be that because of the halting 
problem, for any static analyzer that you present, I can construct a 
program that either contains an error that either your analyzer will not 
catch, or for which it will generate a false positive.  It just so 
happens that constructing such examples for standard C is very easy.

rg



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