User Manual sec. 3.4.4 Type defaulting in GHCi

[Simon Peyton-Jones]

In this case there are no type classes involved, so GHC defaults the
element type of the list to ().  It can hardly leave it as an unbound
\alpha

Simon

| -----Original Message-----
| From: Wolfgang Thaller [mailto:wolfgang.thaller at gmx.net]
| Sent: 02 March 2005 18:42
| To: Simon Peyton-Jones
| Cc: cvs-ghc at haskell.org
| Subject: Re: User Manual sec. 3.4.4 Type defaulting in GHCi
| 
| Simon Peyton-Jones wrote:
| 
| > I've added a note.  the difference is that is the phrase "or the
Show,
| > Eq, or
| > | > Ord class"
| >
| > Simon
| 
| OK, the text is much clearer now, but it doesn't seem to explain the
| behaviour I'm observing...
| 
| when I do
| 
| Prelude> foo <- return []
| Prelude> :t foo
| foo :: [()]
| 
| ... then there is no type class involved at all. The value is not
| shown, compared or anything.
| 
| Cheers,
| 
| Wolfgang