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Comment by raiflip | Hacker News Reader

What if you need to access 5 resources in a row, any of which can throw exceptions? A monad centralizes the repeated logic in its flatMap function.

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I think the comparison is to something like this

  try:
    user = getUser()
    profile = getProfile(user)
    pic = getProfilePicture(profile)
    thumb = getThumbnail(pic)
    return thumb

  except Missing:
    return None

That example seems a bit odd as a design. You’re throwing an exception to represent a no result, but suppressing it to convert the exception to a none. Monads give you the convenience while being consistent.

Well, the problem here is that using exceptions to implement the program’s logic is considered bad practice.

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