[article] Language Design Deal Breakers

[Nick Sabalausky]

On Sat, 25 May 2013 17:14:13 -0700
Jonathan M Davis <jmdavisProg at gmx.com> wrote:

> On Sunday, May 26, 2013 01:54:36 Timon Gehr wrote:
> > On 05/26/2013 01:39 AM, Jonathan M Davis wrote:
> > > On Sunday, May 26, 2013 00:50:28 Klaim - Joël Lamotte wrote:
> > >> I think this have not been posted yet around here but might be
> > >> interesting
> > >> to the D community as it is actually criticizing several
> > >> languages including D but with an interesting aproach:
> > >> 
> > >> http://sebastiansylvan.wordpress.com/2013/05/25/language-design-deal-brea
> > >> ker s/
> > > 
> > > Interesting article, with a lot of good points, though I don't at
> > > all agree
> > > with his take on unit testing or null pointers.
> > > 
> > > - Jonathan M Davis
> > 
> > What is there to disagree with about the null pointer issue?
> 
> I completely disagree that null pointers are a problem. I don't even
> remember the last time that I dereferenced a null pointer in my code,
> and I think that null can be extremely useful. And yet for whatever
> reason, there are quite a few people who seem to think that it's a
> great cause for bugs. Clearly, they're doing something differently
> than I do.
> 
> Regardless, I don't really want to get into that (there was a
> discussion on it quite recently). Suffice it to so that I don't find
> null pointers to be a problem and am confused at how so many people
> manage to have problems with them.
> 

That's been my experience, too. I definitely would love to have a
nice convenient featherweight type that forces checking-for-null
and then, if ok, emits a type that's statically non-nullable. But that
said, I don't run into null dereferences (in D anyway) nearly as much
as I expect I should.

But, for much the same reason, I am somewhat with the author on
unittests. I definitely find them very important and worthwhile, but my
experience is in-line with "writing unit tests **for everything** very
frequently fails the bang-for-buck test" (emphasis added).

In something nicely static-typed like D, most tests never end up
failing, and actual applications do end up implicitly testing a heck
of a lot anyway. Of course, this doesn't imply that unittests aren't
extremely worthwhile (and I don't think even the author was claiming
otherwise), and unittests have indeed helped me a good deal, but I do
think they definitely have a "point of diminishing returns".

That said, good unittesting tends to be much more important for
libraries. And in dynamic-land, then yea, you probably are royally
screwed if you haven't pedantically unittested the crap out of every
single line of code, under every context and runtime type imaginable.