0
votes
1answer
270 views

When does a Monad become a hammer?

I realize my precursory understanding on Monads is severely lacking in detail considering my knowledge comes mostly from Douglas Crockford's Monads and Gonads talk and complicated with my sevear ...
2
votes
1answer
157 views

Picking a card from a shuffled deck

I'm pretty new to Haskell although I did some ML many moons ago. I'm trying to set up a deck of playing cards, shuffle them and then deal them. I have the deck and shuffle sorted (of a fashion) but ...
1
vote
1answer
208 views

Either Monad and Exceptional Circumstances [duplicate]

I have a function returning an Either such as GetUserFromDb(int id). If the database is offline, should I catch the error in the function and wrap it in a failure / Left case or should I let it ...
2
votes
1answer
124 views

Non-trivial functions that operate on any monad [closed]

I'm looking for examples of interesting methods that take an arbitrary monad and do something useful with it. Monads are extremely general, so methods that operate on monads are widely applicable. On ...
8
votes
1answer
336 views

Better to use error monad with validation in your monadic functions, or implement your own monad with validation directly in your bind?

I'm wondering what's better design wise for usability/maintainability, and what's better as far as fitting with the community. Given the data model: type Name = String data Amount = Out | Some | ...
40
votes
5answers
3k views

Critique of the IO monad being viewed as a state monad operating on the world

The IO monad in Haskell is often explained as a state monad where the state is the world. So a value of type IO a monad is viewed as something like worldState -> (a, worldState). Some time ago I ...
20
votes
3answers
2k views

Different ways to see a monad

While learning Haskell I have faced a lot of tutorials trying to explain what are monads and why monads are important in Haskell. Each of them used analogies so it would be easier to catch the ...
6
votes
1answer
390 views

How Does The Maybe Monad Relate To The Option Type?

I was doing a presentation on F# and was discussing the Option type when someone in the audience asked me if the Option type is F#'s implementation of the maybe monad. I know that's not the case but ...
9
votes
6answers
2k views

Maybe monad vs exceptions

I wonder what are the advantages of Maybe monad over exceptions? It looks like Maybe is just explicit (and rather space-consuming) way of try..catch syntax. update Please note that I'm intentionally ...