monad-transformers
Why the boilerplates when writing new Monad Transformers
This section http://book.realworldhaskell.org/read/monad-transformers.html#id659032 from the book Real World Haskell suggests that when writing a new Monad Transformer, we have to derive instances for[详细]
2023-01-29 14:30 分类:问答Is/Should wrapping functions into a monad transformer be considered bad practice?
Let\'s say we want to use ReaderT开发者_开发问答 [(a,b)] over the Maybe monad, and then we want to do a lookup in the list.[详细]
2023-01-27 11:33 分类:问答Combining StateT and State monads
Lets say I have a function f :: State [Int] Int and a function: g :: StateT [Int] IO Int I want to use f in g and pass the state between them. Is there a library function for[详细]
2023-01-24 01:53 分类:问答How can I write a state monad that does error handling as well?
I need to write a state monad that can also support error handling. I was thinking of using the Either monad for this purpose because it can also provide details about what caused the error. I found a[详细]
2023-01-22 14:28 分类:问答Haskell: lift vs liftIO
In what situations should liftIO be used? When I\'m usi开发者_Python百科ng ErrorT String IO, the lift function works to lift IO actions into ErrorT, so liftIO seems superfluous.lift always lifts from[详细]
2023-01-19 23:23 分类:问答How can I make a Maybe-Transformer MaybeT into an instance of MonadWriter?
I am trying to build a MaybeT-Transformer Monad, based on the example in the Real World Haskell, Chapter Monad Transformers:[详细]
2022-12-29 01:18 分类:问答Has anyone ever encountered a Monad Transformer in the wild?
In my area of business - back office IT for a financial institution - it is very common for a software component to carry a global configuration around, to log its progress, to have some kind of error[详细]
2022-12-28 19:37 分类:问答Type error while trying to implement the (>>=) function in order to create a custom monad transformer
I\'m trying to create a monad transformer for a future project, but unfortunately, my implementation of the Monad typeclasse\'s (>>=) function doesn\'t work.[详细]
2022-12-27 01:55 分类:问答Haskell Monad Transformer Stack and Type Signatures
I am attempting to create a stack of monad transformers and am having trouble getting the correct type signatures for my functions. (I\'m still pretty new to Haskell)[详细]
2022-12-17 19:11 分类:问答monad tranformers and stacking of multiple monads
I have function f with signature f :: [a] -> StateT Int Reader b [c], and f\' with signature f\' :: a -> StateT Int Reader b [c][详细]
2022-12-17 11:08 分类:问答