[Haskell-cafe] Re: Type classes and definite types
Max Vasin
max-appolo at mail.ru
Thu May 5 14:15:37 EDT 2005
Bryn Keller <xoltar at xoltar.org> 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.
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