Re: [Haskell-cafe] Monad Description For Imperative Programmer

On 8/1/07, Andrew Wagner wrote:

This seems wrong to me. A monad is, first and foremost, a type constructor class. I'm not sure how you can really compare that to a loop. But perhaps the easiest way to test your definition would be to ask this: How is, for example, the Maybe monad like a loop, in your definition?

As a beginner haskeller coming from an imperative experience, I think I understood what he meant. say you have this code : putStrLn "1" >> putStrLn "2" >> putStrLn "3" you can imagine each of the calls to putStrLn gets implicitly passed a variable (here, the world ) and they happen in succession so it's "like a loop". Except that a loop... loops so the comparison is far fetched.