Re: Proposal: Add concatMapM function (#2042)

On 2008-02-01, Roman Leshchinskiy wrote:

Aaron Denney wrote:

...

On 2008-02-01, Roman Leshchinskiy wrote:

...

Bulat Ziganshin wrote:

...

the right way to deal with "modifiers" is to attach them to the Handle itself like this:

f <- openFile "name" >>= withLocking >>= withEncoding utf8 IMO, global state is never "the right way" if it can be avoided. It will always lead to problems. Especially in a functional language like Haskell.

This isn't global state, but local to the handle, and only affects where the handle is passed in. It's just extending an opaque data type.

If I can destructively change the encoding assocated with a Handle, then it's global state.

Right. But the example given doesn't necessarily have that. x <- [5, 6] >>= (return .) (+ 1) No modification is going on, but return of new values. I don't know how Bulat's stream library is implemented, but I expected a new handle wrapping the old to be returned. -- Aaron Denney -><-