[PRL] Type question...

[Riccardo Pucella]

> 
> Pascal used to assign types to this kind of program :-)
> (not quite the (f f n) part) and I bet you can still get
> it thru the C type checker but I assume you mean "sound"
> type system (and so did everyone else who responded).

If only because C has only a notion of a function type that does not specify what the functions args and return types are. (At least to a first approximation.)

> 
> I wish regular programmers could distinguish these
> two kinds of systems.

I like to think of the distinction as between type systems that are used to make sure you do not use values wrongly (sound type systems), versus type systems that are used for conveying representation information - and the latter is definitely what is going on in C. 


> 
> Why don't you post this kind of question on a forum
> where you can evaluate the reactions of regular
> programmers. I wonder how much this idea of 'safety'
> has sunk in (and what this says about PL education
> at the undergraduate level. I used to cover Type
> Soundness in "311" aka "660". I doubt it is still
> mentioned.)

I think Java has helped in that regard - at least for the average programmer. They may not be able to put it into words that crisply, but they have much more of a sense of soundness than the C programmers (or Pascal programmers) of yore.


 Cheers,
 R