Recent questions tagged functional

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functional programming - Tail-recursion on trees

I have a data structure, datatype 'a tree = Leaf | Branch of 'a tree * 'a * 'a tree and I want ... does it give any speed benefits in practice? See Question&Answers more detail:os...

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

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functional programming - Could I ask for physical analogies or metaphors for recursion?

I am suddenly in a recursive language class (sml) and recursion is not yet physically sensible for me. I'm ... any such models you could share? See Question&Answers more detail:os...

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

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functional programming - Modify bound variables of a closure in Python

Is there any way to modify the bound value of one of the variables inside a closure? Look at the example to understand it ... # 0 + 3 +1 == 4 See Question&Answers more detail:os...

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

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functional programming - Pass a typed function as a parameter in Dart

I know the Function class can be passed as a parameter to another function, like this: void doSomething(Function ... passed as a parameter? See Question&Answers more detail:os...

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

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functional programming - Assisting Agda's termination checker

Suppose we define a function f : N o N f 0 = 0 f (s n) = f (n/2) -- this / operator is ... that recursion has been made on a smaller subproblem. See Question&Answers more detail:os...

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

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functional programming - What does -> mean in F#?

I've been trying to get into F# on and off for a while but I keep getting put off. Why? Because ... truly accessible resource that explains it? See Question&Answers more detail:os...

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

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functional programming - So: what's the point?

What is the intended purpose of the So type? Transliterating into Agda: data So : Bool → Set where oh : So true ... would I want to use So? See Question&Answers more detail:os...

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

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functional programming - While or Tail Recursion in F#, what to use when?

Ok, only just in F# and this is how I understand it now : Some problems are recursive in nature (building or reading ... anyway? If so : why ? See Question&Answers more detail:os...

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

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functional programming - Removing elements with Array.map in JavaScript

I would like to filter an array of items by using the map() function. Here is a code snippet: var ... intended to run in a browser. See Question&Answers more detail:os...

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

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functional programming - Ruby's yield feature in relation to computer science

I recently discovered Ruby's blocks and yielding features, and I was wondering: where does this fit in terms ... , or something more specific? See Question&Answers more detail:os...

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

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functional programming - Are there problems that cannot be written using tail recursion?

Tail recursion is an important performance optimisation stragegy in functional languages because it allows ... conversion automatically? See Question&Answers more detail:os...

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

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functional programming - Using partial functions in Scala - how does it work?

I'm new to Scala, I'm using 2.9.1, and I'm trying to get my head around how to use partial functions. I ... will help, so I'll do that too. See Question&Answers more detail:os...

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

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functional programming - Why are side-effects modeled as monads in Haskell?

Could anyone give some pointers on why the impure computations in Haskell are modelled as monads? I mean monad ... side-effects in it? See Question&Answers more detail:os...

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

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functional programming - How to enumerate a recursive datatype in Haskell?

This blog post has an interesting explanation of how to use the Omega monad to enumerate an arbitrary grammar diagonally. ... $ take 10 $ a See Question&Answers more detail:os...

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

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functional programming - Cross product in Scala

I want to have a binary operator cross (cross-product/cartesian product) that operates with traversables in Scala ... something like scalaz)? See Question&Answers more detail:os...

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

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functional programming - Sampling sequences of random numbers in Haskell

I need small lists of gaussian random numbers for a simulation and so I tried the following: import System.Random ... do I escape this trap? See Question&Answers more detail:os...

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

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functional programming - Can I zip more than two lists together in Scala?

Given the following Scala List: val l = List(List("a1", "b1", "c1"), List("a2", "b2", "c2"), List ... the simplest, as it uses a native method. See Question&Answers more detail:os...

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

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functional programming - What is a function literal in Scala?

What is a function literal in Scala and when should I use them? See Question&Answers more detail:os...

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

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functional programming - How do I identify immutable objects in Java

In my code, I am creating a collection of objects which will be accessed by various threads in a ... will have threading-savvy reviewers. See Question&Answers more detail:os...

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

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functional programming - Does Java support Currying?

I was wondering if there is any way to pull that in Java. I think it is not possible without native support for closures. See Question&Answers more detail:os...

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

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functional programming - python list comprehensions; compressing a list of lists?

guys. I'm trying to find the most elegant solution to a problem and wondered if python has anything built-in for ... but I really want a list. See Question&Answers more detail:os...

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

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functional programming - Tail recursive function to find depth of a tree in Ocaml

I have a type tree defined as follows type 'a tree = Leaf of 'a | Node of 'a * 'a tree * 'a ... to write this function in tail recursive way? See Question&Answers more detail:os...

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

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functional programming - What are "n+k patterns" and why are they banned from Haskell 2010?

When reading Wikipedia's entry on Haskell 2010 I stumbled across this: -- using only prefix notation and n+k- ... more allowed in Haskell 2010? See Question&Answers more detail:os...

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

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functional programming - Should do-notation be avoided in Haskell?

Most Haskell tutorials teach the use of do-notation for IO. I also started with the do-notation, but that makes my ... the code more FP than IO. See Question&Answers more detail:os...

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

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functional programming - When and why should one use Applicative Functors in Scala

I know that Monad can be expressed in Scala as follows: trait Monad[F[_]] { def flatMap[A, B](f: A => ... I should use it instead of flatMap ? See Question&Answers more detail:os...

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

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functional programming - What is the exact definition of a closure?

I've read through previous topics on closures on stackflow and other sources and one thing is still ... misunderstanding the exact definition? See Question&Answers more detail:os...

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

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functional programming - Does Ruby perform Tail Call Optimization?

Functional languages lead to use of recursion to solve a lot of problems, and therefore many of them ... perform tail call optimization? See Question&Answers more detail:os...

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

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functional programming - Using Either to process failures in Scala code

Option monad is a great expressive way to deal with something-or-nothing things in Scala. But what if one ... on refactoring the above code. See Question&Answers more detail:os...

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

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