On May 5, 2013, at 12:51 PM, Laurent wrote: > On Sun, May 5, 2013 at 6:44 PM, Matthias Felleisen <matth...@ccs.neu.edu> > wrote: > > C++ has tried this tack for some time. > > Sounds like it has failed then. > > I can see doing for built-ins but how would you go about programmer-created > operations? Trust the programmer? -- Matthias > > Well, I guess some checks can be added, but I don't see the difference > between attaching bad properties to a newly created operator and defining a > buggy procedure.
I think it is one thing to say (define (fahrenheit->celsius f) 32) and another to attach "associative" to the floating-point + operator. Since we all write examples first and translate then into test suites before we code, finding a bug in fahrenheit->celsius is straightforward and supported by our support mechanisms. If you don't trust your tests, attach contracts to your procedures because they generalize tests in a natural way. Finding bugs in false claims about functions is much less supported at the moment. Perhaps random testing or model checking or something like that may help along here. -- Matthias
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