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  1. import Data.IORef
  2.  
  3. main = do
  4.   xs <- newIORef []
  5.   modifyIORef xs (1:)
  6.   modifyIORef xs (2:)
  7.   xs <- readIORef xs
  8.   print xs
Success #stdin #stdout 0s 4652KB
comments (?)
stdin 
Standard input is empty
stdout 
[2,1]
https://ideone.com/0Gv8fV
language:
Haskell (ghc 8.4.4)
created:
9 years ago
visibility:
public

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