I have two non-overlapping sets of types and want to make other set which is union of these two. Code sample:
Apparently, my type signature was off. I\'ve since found out why. Now, I\'m interested in knowing mor开发者_运维技巧e about the GHCI inferred signature on my typo. I was trying to get this code to wor
Here are my attempts so far: module Main where data FooT = One | Two deriving (Show, Read) {- That is what I want
I read William Cook\'s \"On Data Abstraction, Revisited\", and re-read Ralf Laemmel\'s \"The expression lemma\" to try to understand how to apply the former paper\'s开发者_如何学JAVA ideas in Haskell.
Is it possible to implement Haskell typecla开发者_如何转开发sses in C++? If yes, then how?There\'s a few papers on this, which might be useful as background reading:
When compiling my Haskell application with the -Wall option, GHC complains about orphaned instances, for example:
I\'m going through the 99 Haskell problems to build my proficiency with the langua开发者_运维问答ge. On problem 7 (\"Flatten a nested list structure\"), I found myself wanting to define a conditional
Consider this example: applyKTimes :: Integral i => i -> (a -> a) -> a -> a applyKTimes 0 _ x = x
I am trying to build a MaybeT-Transformer Monad, based on the example in the Real World Haskell, Chapter Monad Transformers:
I want to override the default integer constructors in Haskell so they produce strings (mostly for curiosity, but temporarily to make a nice input alternative for LaTeX\'s \\frac{}{} inconvenience).