Haskell Language IO Checking for end-of-file conditions
Example
A bit counter-intuitive to the way most other languages' standard I/O libraries do it, Haskell's isEOF does not require you to perform a read operation before checking for an EOF condition; the runtime will do it for you.
import System.IO( isEOF )
eofTest :: Int -> IO ()
eofTest line = do
end <- isEOF
if end then
putStrLn $ "End-of-file reached at line " ++ show line ++ "."
else do
getLine
eofTest $ line + 1
main :: IO ()
main =
eofTest 1
Input:
Line #1.
Line #2.
Line #3.
Output:
End-of-file reached at line 4.
