Thanks, looks great! I've merged it into the Github tree. On Sat, Jan 28, 2012 at 8:36 PM, Myles C. Maxfield <[email protected]> wrote: > Ah, yes, you're completely right. I completely agree that moving the > function into the Maybe monad increases readability. This kind of function > is what the Maybe monad was designed for. > > Here is a revised patch. > > > On Sat, Jan 28, 2012 at 8:28 AM, Michael Snoyman <[email protected]> > wrote: >> >> On Sat, Jan 28, 2012 at 1:20 AM, Myles C. Maxfield >> <[email protected]> wrote: >> > the fromJust should never fail, beceause of the guard statement: >> > >> > | 300 <= code && code < 400 && isJust l'' && isJust l' = Just $ req >> > >> > Because of the order of the && operators, it will only evaluate fromJust >> > after it makes sure that the argument isJust. That function in >> > particular >> > shouldn't throw any exceptions - it should only return Nothing. >> > >> > Knowing that, I don't quite think I understand what your concern is. Can >> > you >> > elaborate? >> >> You're right, but I had to squint really hard to prove to myself that >> you're right. That's the kind of code that could easily be broken in >> future updates by an unwitting maintainer (e.g., me). To protect the >> world from me, I'd prefer if the code didn't have the fromJust. This >> might be a good place to leverage the Monad instance of Maybe. >> >> Michael > >
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