On 12/09/10 14:48, bearophile wrote:
Norbert Nemec:
Thank you for your clear explanations of the situation.
With FP/DG, this breaks
down and I believe the best one can do is to implement contracts as
run-time checks in the callee, just as it is done in D.
There is also a mixed strategy: to use run-time checks in the callee for FP/DG,
and something better for the other situations (FP/DG are present in D2
programs, but they aren't used everywhere).
Indeed - this would mean a bare, unchecked interface for each function
and a wrapper that adds contract checks. If the calling code can verify
the contract at compile time, it may call the unchecked version.
Otherwise (like with FP/DG), it will call the checked wrapper.
In fact, this could be understood like a kind of type-casting: A
function interface includes the contract as part of the type
information. If the contract is "casted" away (by assigning the function
to a FP that does not include a contract) the the FP points to the
run-time checked version of the routine.
This concept may even open the road towards FP/DG that include contract
information without getting in the way of lightweight, contract-free
FP/DGs as we have them now.
Greetings,
Norbert
