[PRL] A type-based solution to the "strings problem":

Matthias Felleisen matthias at ccs.neu.edu
Fri Oct 20 09:35:53 EDT 2006


On Oct 20, 2006, at 9:27 AM, William D Clinger wrote:

> Matthis wrote:
>>  HUH?
>
> Cormac proposed a world-wide data base of witnesses to
> subtyping failures, to be extracted automatically from
> application data that fail a run-time type check.  The
> security implications should be obvious.
>
> This isn't an essential part of Cormac's system, but
> the fact he suggested it at all may indicate how much
> thought he has given to the problem of refuting subtyping
> assertions at compile time.
>
> If subtyping assertions are not refuted at compile time,
> then his system amounts to run-time checking with some
> attempt to optimize away some of those checks at compile
> time.  As for the string problem described in the article
> Mitch cited, the essence of the problem is that programmers
> cannot be relied upon to include those run-time checks in
> their programs.  Cormac's system does not address that,
> except by providing an alternative syntax for the assertions
> programmers are using now.

Following in this vein, it is clear that the R*RS editors seem to  
have given this problem no thought either. I am sorry, but I consider  
this remark bordering on useless, just to put some good spin on your  
words. -- Matthias




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