___ ___ _
/ _ \ /\ /\/ __(_)
- / /_\// /_/ / / | | GHC Interactive, version 5.01, for Haskell 98.
+ / /_\// /_/ / / | | GHC Interactive, version 5.03, for Haskell 98.
/ /_\\/ __ / /___| | http://www.haskell.org/ghc/
\____/\/ /_/\____/|_| Type :? for help.
Loading package std ... linking ... done.
-*** WARNING: . is writable by someone else, IGNORING!
-*** WARNING: ./.ghci is writable by someone else, IGNORING!
Prelude> :unset +s +t
Prelude> -- tests for :def, :undef
Prelude> let void m = m >> return ""
Prelude> let echo s = void (putStrLn s)
Prelude> :def echo echo
Prelude> :echo hello, world!
+hello, world!
Prelude>
Prelude> let echo s = return (":! echo " ++ map Char.toUpper s)
-hello, world!
Prelude> :echo hello, world!
+hello, world!
Prelude> :def echo echo
command `echo' is already defined
Prelude> :undef echo
Prelude> :echo hello, world!
HELLO, WORLD!
Prelude> Leaving GHCi.
-hello, world!