From af425841a63ee73603cc09510d95a36e646ddafd Mon Sep 17 00:00:00 2001 From: Tom Smeding Date: Thu, 19 Apr 2018 11:45:46 +0200 Subject: Build with stack --- Utility.hs | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Utility.hs (limited to 'Utility.hs') diff --git a/Utility.hs b/Utility.hs new file mode 100644 index 0000000..a160cb7 --- /dev/null +++ b/Utility.hs @@ -0,0 +1,28 @@ +module Utility where + +import Data.List + +--if any of the predicates returns true, options returns true +options :: [a -> Bool] -> a -> Bool +options l x = any id [f x | f <- l] + +fixpoint :: (Eq a) => (a -> a) -> a -> a +fixpoint f x = let fx = f x in if fx == x then x else fixpoint f fx + +setcompareBy :: (a -> a -> Bool) -> [a] -> [a] -> Bool +setcompareBy _ [] [] = True +setcompareBy _ [] _ = False +setcompareBy _ _ [] = False +setcompareBy p a@(x:xs) b = length a == length b && setcompareBy p xs (deleteBy p x b) + +deleteIndex :: Int -> [a] -> [a] +deleteIndex 0 (_:xs) = xs +deleteIndex i (x:xs) | i > 0 = x : deleteIndex (i-1) xs + +fromLeft :: Either a b -> a +fromLeft (Left a) = a +fromLeft (Right _) = undefined + +fromRight :: Either a b -> b +fromRight (Left _) = undefined +fromRight (Right b) = b -- cgit v1.2.3-54-g00ecf