GHC.Types consturctors with #

[Larry Evans]

http://www.haskell.org/ghc/docs/6.10.2/html/libraries/ghc-prim/GHC-Types.html

contains:

data Int = I# Int#

What does I# Int# mean?  I've tried a simple interpretation:

  Prelude GHC.Types> I# 5#

  <interactive>:1:5: parse error (possibly incorrect indentation)
  Prelude GHC.Types>

but obviously that failed :(

TIA.

-Larry