Just before Section D.1 there is the sentence When inferring the context for the derived instances, type synonyms must be expanded out first.
I don't understand it. Which type synonyms need expansion? All the u_n are type variables. Besides, this would make deriving even more horrible than it is. It would require knowledge about type synonyms. I thought that it should be possible to derive instances, only knowing the type definition with its deriving clause. Furthermore the next sentence in D reads: Free names in the declarations d are all defined in the Prelude; the qualifier `Prelude.' is implicit here. Well, `Prelude' does not necessarily refer to the builtin prelude. I suppose the sentence should actually be the same as the statement at the beginning of Chapter 3 (Expressions). Naturally this makes clear that it is actually impossible to correctly build a tool like DrIft. There is no safe way in Haskell to refer to the builtin prelude... Ciao, Olaf -- OLAF CHITIL, Dept. of Computer Science, The University of York, York YO10 5DD, UK. URL: http://www.cs.york.ac.uk/~olaf/ Tel: +44 1904 434756; Fax: +44 1904 432767 _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
