fork download 
  1. class BoolLike a where
  2.   isTrue :: a -> Bool
  3.  
  4. instance BoolLike Bool where
  5.   isTrue = id
  6.  
  7. instance BoolLike [a] where
  8.   isTrue = not . null
  9.  
  10. (&.&) :: BoolLike a => a -> a -> a
  11. x &.& y
  12.   | isTrue x = y
  13.   | otherwise = x
  14.  
  15. (|.|) :: BoolLike a => a -> a -> a
  16. x |.| y
  17.   | isTrue x = x
  18.   | otherwise = y
  19.  
  20. main = do
  21.   print $ [] |.| [1, 2 ,3]
  22.   print $ [] &.& [1, 2 ,3]
  23.  
Success #stdin #stdout 0s 6224KB
comments (?)
stdin 
Standard input is empty
stdout 
[1,2,3]
[]
https://ideone.com/XqzxSB
language:
Haskell (ghc 8.4.4)
created:
11 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!