[Haskell-cafe] RE: [Haskell] boilerplate boilerplate

Claus Reinke claus.reinke at talk21.com
Thu May 24 05:54:58 EDT 2007

| according to the most recent status report, the syntax is not quite
| settled yet, so what is in ghc head might still change. more info here:
|     http://haskell.org/haskellwiki/GHC/StandAloneDeriving

>Indeed... but nothing much is happening at the moment because there's
>not been much feedback so it's drifted off the radar (so to speak).  
>Refining the wiki and evolving a consensus would be great.

feedback, as requested:-)

- i definitely would like to have standalone deriving, not just in ghc

    (in HaRe, we used to run a script over the various Programatica
    ast sources to extract all the data types we needed to run DrIFT 
    over, to get ast traversal operations; the only alternative would 
    have been to modify their sources, but those were evolving 
    separately; the same problem has arisen again and again, be it 
    template haskell asts or ghc api asts or Language.Haskell or ..)

- syntaxwise, i'm partial to 'derived instance ..', but i can see the
    appeal of 'instance .. derived' (what comes after the instance
    head determines what is going on: 'where..' / 'derived' / '' )

- there should at least be the option of specifying the context
    (if one wants context inference, that is a separate issue which
    should be handled consistently in all instances)

does that help to keep it on the radar?-)

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