Recent questions tagged haskell

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OK, so I realise that I will probably regret this for the rest of my life, but... How does Djinn actually ... relates to Haskell source 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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798 views

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haskell - I taught ghci to compile my StackOverflow posts. Can I make it slicker?

Haskell Stack Overflow layout preprocessor module StackOverflow where -- yes, the source of this post compiles as is ... for .so files? See Question&Answers more detail:os...

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

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973 views

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haskell - How can I understand "(.) . (.)"?

I believe I understand fmap . fmap for Functors, but on functions it's hurting my head for months now. I ... or intuition I'm missing. See Question&Answers more detail:os...

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

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967 views

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haskell - Algorithm for type checking ML-like pattern matching?

How do you determine whether a given pattern is "good", specifically whether it is exhaustive and non-overlapping ... for arbitrary data types? See Question&Answers more detail:os...

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

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923 views

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haskell - What exactly makes Option a monad in Scala?

I know what the monads are and how to use them. What I don't understand is what makes, let's say, Option a ... be a monad by default? Why not? See Question&Answers more detail:os...

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

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764 views

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haskell - Fixing issues noted by ghc-pkg check

It's rather nice that ghc-pkg check will list broken packages, and why they are broken. But as far as ... ? (Preferably not reinstall GHC) See Question&Answers more detail:os...

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

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918 views

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haskell - the seq function and strictness

I have been wondering about this a lot, but I haven't been able to find anything about it. When using ... on the functionality of this function. See Question&Answers more detail:os...

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

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1.6k views

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haskell - Printing elements of a list on new lines

I am trying to print the elements of my list onto new lines, but i cant get it to work; printElements :: [String] -> ... 4"] would give: 1 2 3 4 See Question&Answers more detail:os...

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

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836 views

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haskell - FRP - Event streams and Signals - what is lost in using just signals?

In recent implementations of Classic FRP, for instance reactive-banana, there are event streams and signals, which are ... them changes (<@>). See Question&Answers more detail:os...

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

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haskell - Where do values fit in Category of Hask?

So we have Category of Hask, where: Types are the objects of the category Functions are the morphisms from ... the question makes sense :) See Question&Answers more detail:os...

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

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746 views

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haskell - Writing Algebraic Data Type in Scala

In Haskell, I can define a Tree: data Tree a = Empty | Node a (Tree a) (Tree a) How could I write this in ... for Node to match Tree's type, a. See Question&Answers more detail:os...

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

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951 views

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haskell - Differences between functors and endofunctors

Can someone explain in simple terms the difference between the two? I'm not fully understanding the part where ... versus being just functors. See Question&Answers more detail:os...

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

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893 views

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haskell - Specialization with Constraints

I'm having problems getting GHC to specialize a function with a class constraint. I have a minimal example ... this question is still relevant. See Question&Answers more detail:os...

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

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798 views

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haskell - When would I want to use a Free Monad + Interpreter pattern?

I'm working on a project that, amongst other things, involves a database access layer. Pretty normal, really. In ... pattern? If so, what? See Question&Answers more detail:os...

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

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854 views

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haskell - Can I constrain a type family?

In this recent answer of mine, I happened to crack open this old chestnut (a program so old, half of ... check that the instances satisfy them? See Question&Answers more detail:os...

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

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1.0k views

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haskell - Curious about the HashTable performance issues

I read that hash tables in Haskell had performance issues (on the Haskell-Cafe in 2006 and Flying Frog Consultancy' ... " been fixed in GHC? See Question&Answers more detail:os...

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

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894 views

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haskell - Arrows are exactly equivalent to applicative functors?

According to the famous paper Idioms are oblivious, arrows are meticulous, monads are promiscuous, the expressive power of ... $ first <$> f See Question&Answers more detail:os...

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

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989 views

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haskell - ST Monad == code smell?

I'm working on implementing the UCT algorithm in Haskell, which requires a fair amount of data juggling. ... but immutable structures outside. See Question&Answers more detail:os...

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

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889 views

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haskell - What is the relationship between unboxed types and strictness?

Unboxed types, like Int#, and strict functions, like f (!x) = ..., are something different, but I ... unboxed types and enforcing strictness? See Question&Answers more detail:os...

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

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1.1k views

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haskell - How can I get nth element from a list?

How can I access a list by index in Haskell, analog to this C code? int a[] = { 34, 45, 56 }; return a[1]; See Question&Answers more detail:os...

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

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991 views

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haskell - What are the pros and cons of Enumerators vs. Conduits vs. Pipes?

I'd like to hear from someone with a deeper understanding than myself what the fundamental differences are between ... a high-level overview. See Question&Answers more detail:os...

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

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1.2k views

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haskell - Why can I not make String an instance of a typeclass?

Given: data Foo = FooString String class Fooable a where --(is this a good way to name this?) toFoo :: a ... extra flag. Is this a good idea? See Question&Answers more detail:os...

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

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1.1k views

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haskell - My cabal packages are FUBAR; how can I purge them and start over?

I forgot to enable building libs for profiling in my ~/.cabal/config before installing a bunch of packages on a ... How do I do that correctly? See Question&Answers more detail:os...

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

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1.0k views

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haskell - What is the benefit of purely functional data structure?

There are large number of texts on data structures, and libraries of data structures code. I understand that ... structure that operates purely. See Question&Answers more detail:os...

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

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845 views

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haskell - Writing cojoin or cobind for n-dimensional grid type

Using the typical definition of type-level naturals, I've defined an n-dimensional grid. {-# LANGUAGE KindSignatures # ... , then there you go. See Question&Answers more detail:os...

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

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1.0k views

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haskell - Why is GHC so large/big?

Is there a simple answer: Why is GHC so big? OCaml: 2MB Python: 15MB SBCL: 9MB OpenJRE - 26MB GHC: 113MB ... "; this is a technical question. See Question&Answers more detail:os...

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

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956 views

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haskell - Is there a visual modeling language or style for the functional programming paradigm?

UML is a standard aimed at the modeling of software which will be written in OO languages, and goes hand in ... is looking to provide for. See Question&Answers more detail:os...

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

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869 views

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haskell - What are the benefits of applicative parsing over monadic parsing?

There seems to be a consensus that you should use Parsec as an applicative rather than a monad. What are ... abstraction Is monadic parsing out? See Question&Answers more detail:os...

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

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