[Haskell-cafe] Re: Type classes and definite types

5 May 2005


      Bryn Keller  writes:
...
Hi folks,
Hello,
[skip]
The problem is that getFieldValue returns a value of type (SqlBind a)
=> a. That is, there's no type information associated with this return
value other than it's a valid  SQL value. There are no operations in
the SqlBind class, it's just a marker as near as I can tell. 
As of HSQL 1.4 this class has method 
toSqlValue :: a -> String
which probably can help you (I really don't know).
Some RTFSing shows that in most cases toSqlValue is implemented with show.

--
WBR,
Max Vasin.