Recent questions tagged monads

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monads - Is mapM in Haskell strict? Why does this program get a stack overflow?

The following program terminates correctly: import System.Random randomList = mapM (\_->getStdRandom (randomR (0, ... in the standard library. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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monads - What's the idiomatic way to handle multiple `Option<T>` in Rust?

Since I'm fairly new to Rust, I need guidance on how error handling is done idiomatically. I find the error-handling ... bind(x, f), g) } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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monads - Simulating interacting stateful objects in Haskell

I'm currently writing a Haskell program that involves simulating an abstract machine, which has internal state, takes ... of problem in Haskell. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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monads - Using Eithers with Scala "for" syntax

As I understand it, Scala "for" syntax is extremely similar to Haskell's monadic "do" syntax. In Scala, "for" ... Either, how could I do that? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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monads - Why is there no << in the Haskell standard library?

The Monad class defines a >> method, which sequences two monadic actions: >> :: Monad m => m a -> m ... x <- doSomethingElse >>= doSomething. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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330 views

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monads - Why can't Haskell be tricked into performing IO operations by using strict evaluation?

I'm just learning Haskell and IO monads. I'm wondering why wouldn't this force the program to output "hi" ... IO operations inside "safe" code? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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333 views

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monads - Why is there no << in the Haskell standard library?

The Monad class defines a >> method, which sequences two monadic actions: >> :: Monad m => m a -> m ... x <- doSomethingElse >>= doSomething. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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350 views

1 answer

monads - Why can't Haskell be tricked into performing IO operations by using strict evaluation?

I'm just learning Haskell and IO monads. I'm wondering why wouldn't this force the program to output "hi" ... IO operations inside "safe" code? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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392 views

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monads - How to apply higher order function to an effectful function in Haskell?

I have too functions: higherOrderPure :: (a -> b) -> c effectful :: Monad m => (a -> m b) I'd like ... `someOp` func :: Either String (Dia Any) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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266 views

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monads - Must mplus always be associative? Haskell wiki vs. Oleg Kiselyov

The Haskell wikibook asserts that Instances of MonadPlus are required to fulfill several rules, just as instances ... the right interpretation.) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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612 views

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monads - Is Haskell's mapM not lazy?

UPDATE: Okay this question becomes potentially very straightforward. q <- mapM return [1..] Why does this ... impression that mapM can lazily See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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