On 30 Jan 2008, at 7:19 PM, Anton van Straaten wrote:
Derek Elkins wrote:
It isn't something that would throw a C programmer off, but it is something that could confuse a pure Haskell programmer. And the only way I could be sure of radians versus degrees was by trying it out, not a great strategy for determining the implementation of functions! Uh, why not? Often that's exactly what I do as checking even conveniently located documentation is more time consuming than just
On Thu, 2008-01-31 at 02:18 +0000, Neil Mitchell wrote: ... trying it.
I agree, but at the risk of veering uncharacteristically off-topic for haskell-cafe, I think it's an interesting example of the degree of assurance about correctness we're willing to accept in practice, in real development.
We discover a function called, say, "cos", probably by guessing it's name, run a very small number of simple tests on it, see the answers we expect, and decide that it's the function we want.
True enough; more complicated tests seem to reveal the opposite conclusion:
quickCheck $ \ x -> cos (x + 2*pi) == cos x Falsifiable, after 2 tests: -1.0
jcc