Re: [Chicken-hackers] Clean versus pure in types.db

[Jörg F . Wittenberger]

On Mar 12 2012, John Cowan wrote:

> Felix scripsit:
>
> > I used "pure" only half-heartedly. Strictly speaking a "pure" function 
> > should not even throw an error, the "pure" meaning: this procedure will 
> > not have any effect whatsoever, regardless of arguments (so it can be 
> > removed if the result is unused). "(length 42)" will signal an error, so 
> > it is not pure.
>
> Frankly, if it were treated as pure I doubt if any Real World programs 
> would be affected.

While I'd bet what is located at the lower end of my spine on that.  ;-)

> I've never had much sympathy for the CL and R6RS 
> viewpoint that programmers should be able to count on a run-time 
> exception being raised when they've done something silly.

Just because silly programs exist.  I've contributed to that pile
myself.

While I agree that programs SHOULD not depend on such r/t exceptions
eventually they do.

But your are right, John: it would be an interesting option to have
a compiler switch, which would treat all "clean" declarations as
if they where declared "pure" (e.g., as if things where one level
stricter than known to work so far).

/Jörg