API for looking-up/retrieving Haddock comments?

[Simon Marlow]

On 04/08/2012 08:33, Herbert Valerio Riedel wrote:
> Simon Hengel <sol at typeful.net> writes:
>
> [...]
>
>> I have the following in my .ghci:
>>
>>      -- hoogle integration
>>      :def hoogle \q -> return $ ":! hoogle --color=true --count=15   \"" ++ q ++ "\""
>>      :def doc    \q -> return $ ":! hoogle --color=true --info       \"" ++ q ++ "\""
>
> [...]
>
> thanks, this already looks very promising; there's just a few minor issues
> I'm a bit dissatisfied with the GHCi integration:
>
>   1. it doesn't take into account the currently visible module namespaces that GHCi
>      has currently loaded (as opposed to `:info` and `:type`):
>
> ,----
> | Prelude> import Data.IntMap
> |
> | Prelude Data.IntMap> :info fromList
> | fromList :: [(Key, a)] -> IntMap a 	-- Defined in `Data.IntMap'
> |
> | Prelude Data.IntMap> :type  fromList
> | fromList :: [(Key, a)] -> IntMap a
> |
> | Prelude Data.IntMap> :doc fromList
> | Searching for: fromList
> | Data.HashTable fromList :: Eq key => (key -> Int32) -> [(key, val)] -> IO (HashTable key val)
> |
> | Convert a list of key/value pairs into a hash table. Equality on keys
> | is taken from the Eq instance for the key type.
> |
> | From package base
> | fromList :: Eq key => (key -> Int32) -> [(key, val)] -> IO (HashTable key val)
> |
> | Prelude Data.IntMap>
> `----
>
>   2. tab-completion (as it works for `:type` and `:doc`) doesn't extend
>      to `:doc`
>
>
> I guess both items could be improved upon by extending GHCi to provide
> an additional `:def` facility tailored to Haskell symbols allowing to
> pass more meta-information (such as package and module information) into
> the resulting command string... would something like that have any
> chance of being accepted upstream?

I think it would make more sense to just add :doc to the GHCi front-end, 
relying on the user having already installed hoogle.  We could give a 
sensible error message if you don't have Hoogle installed.

Cheers,
	Simon