On Tue, Jan 20, 2015 at 1:36 PM, Volker Wysk
What is a "hole"?
https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/typed-holes.... When I replace "_exit" with "foo", it produces a "not in scope" error, as
expected. What is special about "_exit"? It doesn't occur in the Haskell Hierarchical Libraries.
The leading underscore invokes the typed holes extension. If you want to use such names, you'll need {-# LANGUAGE NoTypedHoles #-} as the first line of the source file. (I am not sure why this extension was enabled by default.) -- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net