[Haskell-beginners] What does the "!n" mean?

[John M. Dlugosz]

On 3/26/2014 8:26 PM, yi lu wrote:
> http://www.haskell.org/ghc/docs/7.6.3/html/users_guide/bang-patterns.html
>
> Do you mean this?

Thanks!  I missed it when scanning through the GHC docs.