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|
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
module Haddock.Backends.Hyperlinker.Ast
( enrich
, RichToken(..), TokenDetails(..), rtkName
) where
import Haddock.Backends.Hyperlinker.Parser
import qualified GHC
import Control.Applicative
import Data.Data
import Data.Maybe
data RichToken = RichToken
{ rtkToken :: Token
, rtkDetails :: Maybe TokenDetails
}
data TokenDetails
= RtkVar GHC.Name
| RtkType GHC.Name
| RtkBind GHC.Name
| RtkDecl GHC.Name
| RtkModule GHC.ModuleName
rtkName :: TokenDetails -> Either GHC.Name GHC.ModuleName
rtkName (RtkVar name) = Left name
rtkName (RtkType name) = Left name
rtkName (RtkBind name) = Left name
rtkName (RtkDecl name) = Left name
rtkName (RtkModule name) = Right name
-- | Add more detailed information to token stream using GHC API.
enrich :: GHC.RenamedSource -> [Token] -> [RichToken]
enrich src =
map $ \token -> RichToken
{ rtkToken = token
, rtkDetails = enrichToken token detailsMap
}
where
detailsMap = concatMap ($ src)
[ variables
, types
, decls
, binds
, imports
]
-- | A map containing association between source locations and "details" of
-- this location.
--
-- For the time being, it is just a list of pairs. However, looking up things
-- in such structure has linear complexity. We cannot use any hashmap-like
-- stuff because source locations are not ordered. In the future, this should
-- be replaced with interval tree data structure.
type DetailsMap = [(GHC.SrcSpan, TokenDetails)]
lookupBySpan :: Span -> DetailsMap -> Maybe TokenDetails
lookupBySpan tspan = listToMaybe . map snd . filter (matches tspan . fst)
enrichToken :: Token -> DetailsMap -> Maybe TokenDetails
enrichToken (Token typ _ spn) dm
| typ `elem` [TkIdentifier, TkOperator] = lookupBySpan spn dm
enrichToken _ _ = Nothing
-- | Obtain details map for variables ("normally" used identifiers).
variables :: GHC.RenamedSource -> DetailsMap
variables =
everything (<|>) var
where
var term = case cast term of
(Just (GHC.L sspan (GHC.HsVar name))) ->
pure (sspan, RtkVar name)
_ -> empty
-- | Obtain details map for types.
types :: GHC.RenamedSource -> DetailsMap
types =
everything (<|>) ty
where
ty term = case cast term of
(Just (GHC.L sspan (GHC.HsTyVar name))) ->
pure (sspan, RtkType name)
_ -> empty
-- | Obtain details map for identifier bindings.
--
-- That includes both identifiers bound by pattern matching or declared using
-- ordinary assignment (in top-level declarations, let-expressions and where
-- clauses).
binds :: GHC.RenamedSource -> DetailsMap
binds =
everything (<|>) (fun `combine` pat)
where
fun term = case cast term of
(Just (GHC.FunBind (GHC.L sspan name) _ _ _ _ _ :: GHC.HsBind GHC.Name)) ->
pure (sspan, RtkBind name)
_ -> empty
pat term = case cast term of
(Just (GHC.L sspan (GHC.VarPat name))) ->
pure (sspan, RtkBind name)
_ -> empty
-- | Obtain details map for top-level declarations.
decls :: GHC.RenamedSource -> DetailsMap
decls (group, _, _, _) = concatMap ($ group)
[ concat . map typ . concat . map GHC.group_tyclds . GHC.hs_tyclds
, everything (<|>) fun
]
where
typ (GHC.L _ t) = case t of
GHC.DataDecl name _ defn _ ->
[decl name] ++ concatMap con (GHC.dd_cons defn)
_ -> pure . decl $ GHC.tcdLName t
fun term = case cast term of
(Just (GHC.FunBind (GHC.L sspan name) _ _ _ _ _ :: GHC.HsBind GHC.Name))
| GHC.isExternalName name -> pure (sspan, RtkDecl name)
_ -> empty
con (GHC.L _ t) =
map decl (GHC.con_names t) ++ everything (<|>) fld t
fld term = case cast term of
Just field -> map decl $ GHC.cd_fld_names field
Nothing -> empty
decl (GHC.L sspan name) = (sspan, RtkDecl name)
-- | Obtain details map for import declarations.
--
-- This map also includes type and variable details for items in export and
-- import lists.
imports :: GHC.RenamedSource -> DetailsMap
imports src@(_, imps, _, _) =
everything (<|>) ie src ++ map (imp . GHC.unLoc) imps
where
ie term = case cast term of
(Just (GHC.IEVar v)) -> pure $ var v
(Just (GHC.IEThingAbs t)) -> pure $ typ t
(Just (GHC.IEThingAll t)) -> pure $ typ t
(Just (GHC.IEThingWith t vs)) -> [typ t] ++ map var vs
_ -> empty
typ (GHC.L sspan name) = (sspan, RtkType name)
var (GHC.L sspan name) = (sspan, RtkVar name)
imp idecl =
let (GHC.L sspan name) = GHC.ideclName idecl
in (sspan, RtkModule name)
-- | Check whether token stream span matches GHC source span.
--
-- Currently, it is implemented as checking whether "our" span is contained
-- in GHC span. The reason for that is because GHC span are generally wider
-- and may spread across couple tokens. For example, @(>>=)@ consists of three
-- tokens: @(@, @>>=@, @)@, but GHC source span associated with @>>=@ variable
-- contains @(@ and @)@. Similarly, qualified identifiers like @Foo.Bar.quux@
-- are tokenized as @Foo@, @.@, @Bar@, @.@, @quux@ but GHC source span
-- associated with @quux@ contains all five elements.
matches :: Span -> GHC.SrcSpan -> Bool
matches tspan (GHC.RealSrcSpan aspan)
| saspan <= stspan && etspan <= easpan = True
where
stspan = (posRow . spStart $ tspan, posCol . spStart $ tspan)
etspan = (posRow . spEnd $ tspan, posCol . spEnd $ tspan)
saspan = (GHC.srcSpanStartLine aspan, GHC.srcSpanStartCol aspan)
easpan = (GHC.srcSpanEndLine aspan, GHC.srcSpanEndCol aspan)
matches _ _ = False
-- | Perform a query on each level of a tree.
--
-- This is stolen directly from SYB package and copied here to not introduce
-- additional dependencies.
everything :: (r -> r -> r) -> (forall a. Data a => a -> r)
-> (forall a. Data a => a -> r)
everything k f x = foldl k (f x) (gmapQ (everything k f) x)
-- | Combine two queries into one using alternative combinator.
combine :: Alternative f => (forall a. Data a => a -> f r)
-> (forall a. Data a => a -> f r)
-> (forall a. Data a => a -> f r)
combine f g x = f x <|> g x
|
