[Haskell-cafe] auto-completion for Vim 7

Neil Mitchell ndmitchell at gmail.com
Sun Mar 4 16:19:01 EST 2007

Hi Claus,

> Neil: is there any documentation on the output format? i couldn't find the
> flag in the haddock manual, so i was surprised to see it in haddock --help;
> it works, though, and does seem to generate modules with implementations
> removed, and some declarations simplified?

Documentation isn't my strong point :) It was originally only intended
to be an internal thing for Hoogle, but it does seem generally useful.
Perhaps changing it to --summary, documenting it, and more formally
specifying the output format (along with an AST/printer/parser) would
be a good plan.

> one problem with this is that hoogle.txt is not included with releases, nor
> are the library sources, so this route won't be available for most ghc users.
> that is why my Doc.vim, announced earlier today, extracts information
> somewhat tediously from the haddock html index files that are included
> at least with windows releases.

You can always download hoogle.txt, or perhaps we could supply
summary.txt with the HTML output as the documentation? The GHC people
would have to be the ones to decide it - Hugs doesn't ship with
documentation anyway.

My experience with parsing haddock generated HTML is that its painful,
and usually wrong. The indexes might be a bit clearer, but parsing out
the type signatures and names was a nightmare.

> the haddock --hoogle route has the additional issue that it will miss identifiers
> without type declarations. you could use ghc itself to provide identifier lists:

ghc-haddock will fix that. Extracting names from the index will also
miss those without type signatures.

>     $ ghc -e ":b Data.Char"
>     digitToInt :: Char -> Int
>     data Char
>     type String = [Char]
>     chr :: Int -> Char

I experimented with this as the means for getting information for
Hoogle. It was fine, apart from extracting instances (you needed the
instance and the type both to be in scope, which you can't really do,
or the instance is missed).  The only tip I'd give is make sure you
specify -fglasgow-exts, I remember some issue if that was missed with
functions that were using # in their name - no idea on the exact issue
but that flag fixed it.



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