Brandon J. Van Every wrote: > Thomas Christian Chust wrote: > >> [...] >> all the contract based programming systems I know don't come up with a >> specific language for describing the contracts. I usually see contract >> based programming systems as syntactic sugar allowing you to specify >> arbitrary code which will be run upon entry to and exit from a function. >> > > How is that better than just writing tests then?
Hello, it's not better, but there is an important difference in the mode of operation. Unit tests are usually bundled into a test driver program -- either by hand or by some automatism -- that is run once every time the code changes to find any possible bugs in your library functions. The important point is that each unit test you wrote is *run exactly once* by the test driver program. Contracts are compiled into the library itself when they are enabled and they get *run every time the functions they belong to are called*. So while tests are good for feeding your functions some pathological inputs to see whether they still work, contracts are great to determine whether the functions *and their callers* behave correctly during normal operation of the final program -- and maybe to discover more pathological cases to check for in the test suite ;-) Actually we already have the choice to disable some kind of contract checking in CHICKEN by using the unsafe runtime libraries. cu, Thomas _______________________________________________ Chicken-users mailing list Chicken-users@nongnu.org http://lists.nongnu.org/mailman/listinfo/chicken-users
