The Future of Haskell discussion at the Haskell Workshop

Karl-Filip Faxen kff@it.kth.se
Wed, 10 Sep 2003 11:51:17 +0200


Yes, things are clearer and I rather like the idea. The only
thorny issue is that the update function for field 'wibble'
is formed from but not equal to the field name itself.

In short, the magic thing would be in the 'deriving' clause:

If the data type declares fields with names x_1, ..., x_n
and the class mentioned declares operators y_1, ..., y_k
and set_y_1, ..., set_y_k where {y_1, ..., y_k} is a subset
of {x_1, ..., x_k}, of the appropriate types, then the
corresponding instance declarations are generated.

Cheers,

    /kff