[Haskell-cafe] using the writer monad to better understand foldl and foldr, and haskell debugging techniques in general

Felipe Lessa felipe.lessa at gmail.com
Mon Feb 11 04:55:01 EST 2008

On Feb 11, 2008 7:53 AM, Felipe Lessa <felipe.lessa at gmail.com> wrote:
> read that IORef and do a big tell to the outside Writer monad. I'd say
> that this is a safe use of unsafePerformIO as it shouldn't break
> referential transparency. But without this hack I don't think we could

Well, not really as well. The IO action from unsafePerformIO may be
executed several times, I guess. =)


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