Task

 verify the version/revision of your currently running (compiler/interpreter/byte-compiler/runtime environment/whatever your language uses) and exit if it is too old.
 check whether the variable "bloop" exists and whether the math-function "abs()" is available and if yes compute abs(bloop).


Extra credit

 Report the number of integer variables in global scope, and their sum.


import Data.Version
import Control.Monad
import System.Info
 
minGHCVersion = Version [6, 8] []
 
main = when (compilerName == "ghc" && compilerVersion < minGHCVersion) $
    fail "Compiler too old."