On Feb 27, 2010, at 04:07 , zaxis wrote:
xxxMain = do
timeout <- getEnv "xxx_TIMEOUT"
case timeout of
Just str | [(t, _)] <- reads str -> do
addTimeout t (hPutStrLn stderr "*** TIMEOUT" >> _exit 1)
return ()
_ -> return ()
.......
What does the `|` mean in "Just str | [(t, _)] <- reads str" ?
Is it a logical `or` ?
It's a guard. Same as with function definitions (in fact, function definitions of that form are converted to case expressions).
-- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH
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