The do notation in this instance yields a nice advantage: if you want to switch to a different monad to encapsulate failure you will meely need to swap out the type signature and your function will need no further work. On Aug 4, 2012 7:35 AM, "Matthew" <[email protected]> wrote:
> I'm a somewhat experienced coder but I am relatively new to Haskell. > I've got a question about whether a usage of do notation is idiomatic, > or whether it's better to use pattern matching. > > I've got two functions which take an input and return Maybe SomeType. > If either returns Nothing, I also want to return Nothing. If they both > return something, then I'll return something unrelated. > > With do notation, I can write something like this: > > do > foo <- callFoo x > bar <- callBar x > return (baz) > > Alternatively, there's a straightforward pattern match. After binding > foo, bar in a couple of where clauses: > > case (foo,bar) of (Just x, Just y) -> baz > _ -> Nothing > > So which approach is more idiomatic, do you think? > > Thanks, > - Matthew > > _______________________________________________ > Haskell-Cafe mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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