Tagged Questions
1
vote
1answer
37 views
Recursive Determinant
The following code I devised to compute a determinant:
module MatrixOps where
determinant :: (Num a, Fractional a) => [[a]] -> a
determinant [[x]] = x
determinant mat =
sum [s*x*(determinant ...
3
votes
2answers
112 views
Palindrome test in Haskell
I am new to Haskell and, coming from a OO/procedural programming background, I want to make sure my code follows the functional way of doing things. I built this short module to test if a given string ...
0
votes
0answers
97 views
Could someone profile the space and time complexity of this Haskell snippet?
I'm new to programming and even more new to Haskell, below is a little tid-bit I wrote that operates on a bunch of lists. I am wondering if someone would be kind enough to walk through the function ...
4
votes
2answers
64 views
Is there a way to simple Haskell class instance?
I define a Pixel data with different size like this.
data Pixel = RGB8 Word8 Word8 Word8
| RGBA8 Word8 Word8 Word8 Word8
| RGB16 Word16 Word16 Word16
| RGBA16 Word16 ...
1
vote
0answers
46 views
This is a try at implementing integers in Idris. Any advice or comments are most welcome.
-- tries to implement integers using fold and a generalized notion of 'reduction' instead of
-- utilizing recursion explicitly in all operations./
-- maximum (reasonable) code reuse, information ...
3
votes
1answer
97 views
Help make nested folds look less terse
My Haskell set/map/list folds often become terse and difficult to read. I'm looking for tips on how to make my functional code easier to follow.
I'm working around a bug/feature in a plotting ...
10
votes
4answers
1k views
How to shorten this terrible code?
I am trying to read a line ending in \r\n from a Handle. This is an HTTP header.
I’m fairly new to functional programming, so I tend to use a lot of case expressions and stuff. This makes the code ...
4
votes
2answers
139 views
Writing an infinitely running( while(true) { } ) user input function in haskell
I'm trying to implement a lexer in Haskell. For easy console input and output, I've used an intermediate data type Transition Table.
type TransitionTable = [(Int, Transitions String Int)]
type ...
6
votes
2answers
139 views
Naive Bayes classifier
I just started learning Haskell, and I must say it is unlike anything else. As my first not-entirely-trivial piece of code I tried to write a simple Bayes Classifier. It is in two parts, a classifier ...
4
votes
1answer
307 views
Simple Haskell key value file store
As an exercise in learning Haskell, I implemented a simple key value store, where you can put and get values (as ByteStrings). (For reference this is inspired by this short note describing bitcask's ...
6
votes
4answers
293 views
Can I make this code more Haskelly?
I am very new to functional programming. I wrote this program where the user can enter an integer and it prints the factorial. If the user enters a negative integer or not an integer at all, it'll ...
5
votes
4answers
531 views
Improving my solution to Project Euler problem #1?
I'm trying to compare my own implementation with another solution of ProjectEuler problem #1, which uses a list comprehension:
module Progression1 (sumProgressions) where
import Prelude
...
5
votes
1answer
105 views
Chaining method calls and “bubbling” the results
I need a way to build up a sort of stack of places to search for an item.
What I would like to do is to have each layer searched for an item, and if it is found at that level, then it should be ...
4
votes
2answers
360 views
Enclosing Circle Problem implementation in Haskell
I implemented the algorithm by Pr. Chrystal described here in Haskell so could someone please tell me: Do i have implemented this algorithm correctly?
Initial calling of findPoints takes the first and ...
2
votes
2answers
266 views
Can my solution to TopCoder's BestApproximationDiv2 problem be any better?
Link to problem statement on TopCoder
import Data.Char
import Data.List
import Data.Maybe
showResult :: (Int, Int, Int) -> String
showResult (a, b, x) = show a ++ "/" ++ show b ++ " has "
...
3
votes
1answer
163 views
Most elegant approach to writing list renumbering function
I'm writing a function with the following signature:
(Ord a) => [a] -> [Int]
It's semantics is to find an order-preserving mapping from list of objects to list of Ints.
The version of mine:
...
9
votes
1answer
366 views
Converting simple markup to HTML
This is going to be rather long and generic, so apologies in advance.
I've been reading a lot about Haskell lately, but I've never really programmed anything with it beyond simple experiments in ...
