what is the purpose of arrows?

Posted by Simon on Programmers See other posts from Programmers or by Simon
Published on 2011-10-17T11:40:20Z Indexed on 2012/10/09 15:54 UTC
Read the original article Hit count: 242

Filed under:

functional-programming

|

haskell

I am learning functionnal programming with Haskell, and I try to grab concepts by first understanding why do I need them.

I would like to know the goal of arrows in functional programming languages. What problem do they solve? I checked http://en.wikibooks.org/wiki/Haskell/Understanding_arrows and http://www.cse.chalmers.se/~rjmh/afp-arrows.pdf. All I understand is that they are used to describe graphs for computations, and that they allow easier point free style coding.

The article assume that point free style is generally easier to understand and to write. This seems quite subjective to me. In another article (http://en.wikibooks.org/wiki/Haskell/StephensArrowTutorial#Hangman:_Main_program), a hangman game is implemented, but I cannot see how arrows makes this implementation natural.

I could find a lot of papers describing the concept, but nothing about the motivation.

What I am missing?

© Programmers or respective owner

Related posts about functional-programming

Introducing functional programming constructs in non-functional programming languages

as seen on Programmers - Search for 'Programmers'
This question has been going through my mind quite a lot lately and since I haven't found a convincing answer to it I would like to know if other users of this site have thought about it as well. In the recent years, even though OOP is still the most popular programming paradigm, functional programming… >>> More
Functional programming constructs in non-functional programming languages

as seen on Programmers - Search for 'Programmers'
This question has been going through my mind quite a lot lately and since I haven't found a convincing answer to it I would like to know if other users of this site have thought about it as well. In the recent years, even though OOP is still the most popular programming paradigm, functional programming… >>> More
Does functional programming mandate new naming conventions?

as seen on Stack Overflow - Search for 'Stack Overflow'
I recently started studying functional programming using Haskell and came upon this article on the official Haskell wiki: How to read Haskell. The article claims that short variable names such as x, xs, and f are fitting for Haskell code, because of conciseness and abstraction. In essence, it claims… >>> More
pitfalls/disadvantages of functional programming

as seen on Stack Overflow - Search for 'Stack Overflow'
When would you NOT want to use functional programming? What is it not so good at? I am more looking for disadvantages of the paradigm as a whole, not things like "not widely used", or "no good debugger available". Those answers may be correct as of now, but they deal with FP being a new concept (an… >>> More
Should functional programming be taught before imperative programming?

as seen on Stack Overflow - Search for 'Stack Overflow'
It seems to me that functional programming is a great thing. It eliminates state and makes it much easier to automatically make code run in parallel. Many programmers who were first taught imperative programming styles find it very difficult to learn functional programming, because it is so different… >>> More

Related posts about haskell

Learning Haskell: How to remove an item from a List in Haskell

as seen on Stack Overflow - Search for 'Stack Overflow'
Trying to learn Haskell. I am trying to write a simple function to remove a number from a list without using built-in function (delete...I think). For the sake of simplicity, let's assume that the input parameter is an Integer and the list is an Integer list. Here is the code I have, Please tell me… >>> More
Using Data.Heap in Haskell, or reading Haskell docs for a beginner

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to use Haskells Data.Heap module, but I'm incapable of even using it with integers. The only heap I've been capable of using is "empty", which does not take any arguments. Later on I'll figure out how to instance for my needs, but for now I'd be glad if I was even able to test it with… >>> More
What kind of things are easy in Haskell and hard in Scala, and vice versa?

as seen on Programmers - Search for 'Programmers'
There has been some intermingling of Scala and Haskell communities, and I have noticed now and then people commenting on stuff that's supposed to be easy in Haskell and hard and Scala. Less often (maybe because I read Scala questions, not Haskell ones), I see someone mentioning that something in Scala… >>> More
Haskell's cabal dependency problem with happy

as seen on Programmers - Search for 'Programmers'
I have problems installing ghc-mod on my linux machine. cabal worries about "happy" not being available in versione = 1.17: $ cabal install ghc-mod Resolving dependencies... [1 of 1] Compiling Main ( /tmp/haskell-src-exts-1.14.0-1357/haskell-src-exts-1.14.0/Setup.hs, /tmp/haskell-src-exts-1… >>> More
Understanding Haskell's fibonacci

as seen on Stack Overflow - Search for 'Stack Overflow'
fibs :: [Int] fibs = 0 : 1 : [ a + b | (a, b) <- zip fibs (tail fibs)] This generates the Fibonacci sequence. I understand the behaviour of the guards, of :, zip and tail, but I don't understand <-. What is it doing here? >>> More