{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE DataKinds #-}

module GHC.Parser.Types
   ( SumOrTuple(..)
   , pprSumOrTuple
   , PatBuilder(..)
   , DataConBuilder(..)
   )
where

import GHC.Prelude
import GHC.Types.Basic
import GHC.Types.SrcLoc
import GHC.Types.Name.Reader
import GHC.Hs.Extension
import GHC.Hs.Lit
import GHC.Hs.Pat
import GHC.Hs.Type
import GHC.Utils.Outputable as Outputable
import GHC.Data.OrdList

import Data.Foldable
import GHC.Parser.Annotation
import Language.Haskell.Syntax

data SumOrTuple b
  = Sum ConTag Arity (LocatedA b) [EpaLocation] [EpaLocation]
  -- ^ Last two are the locations of the '|' before and after the payload
  | Tuple [Either (EpAnn EpaLocation) (LocatedA b)]

pprSumOrTuple :: Outputable b => Boxity -> SumOrTuple b -> SDoc
pprSumOrTuple :: forall b. Outputable b => Boxity -> SumOrTuple b -> SDoc
pprSumOrTuple Boxity
boxity = \case
    Sum Int
alt Int
arity LocatedA b
e [EpaLocation]
_ [EpaLocation]
_ ->
      SDoc
parOpen forall doc. IsLine doc => doc -> doc -> doc
<+> forall {doc}. IsLine doc => Int -> doc
ppr_bars (Int
alt forall a. Num a => a -> a -> a
- Int
1) forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr LocatedA b
e forall doc. IsLine doc => doc -> doc -> doc
<+> forall {doc}. IsLine doc => Int -> doc
ppr_bars (Int
arity forall a. Num a => a -> a -> a
- Int
alt)
              forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
parClose
    Tuple [Either (EpAnn EpaLocation) (LocatedA b)]
xs ->
      SDoc
parOpen forall doc. IsLine doc => doc -> doc -> doc
<> ([SDoc] -> SDoc
fcat forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate forall doc. IsLine doc => doc
comma forall a b. (a -> b) -> a -> b
$ forall a b. (a -> b) -> [a] -> [b]
map forall {a} {a}. Outputable a => Either a a -> SDoc
ppr_tup [Either (EpAnn EpaLocation) (LocatedA b)]
xs)
              forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
parClose
  where
    ppr_tup :: Either a a -> SDoc
ppr_tup (Left a
_)  = forall doc. IsOutput doc => doc
empty
    ppr_tup (Right a
e) = forall a. Outputable a => a -> SDoc
ppr a
e

    ppr_bars :: Int -> doc
ppr_bars Int
n = forall doc. IsLine doc => [doc] -> doc
hsep (forall a. Int -> a -> [a]
replicate Int
n (forall doc. IsLine doc => Char -> doc
Outputable.char Char
'|'))
    (SDoc
parOpen, SDoc
parClose) =
      case Boxity
boxity of
        Boxity
Boxed -> (forall doc. IsLine doc => String -> doc
text String
"(", forall doc. IsLine doc => String -> doc
text String
")")
        Boxity
Unboxed -> (forall doc. IsLine doc => String -> doc
text String
"(#", forall doc. IsLine doc => String -> doc
text String
"#)")


-- | See Note [Ambiguous syntactic categories] and Note [PatBuilder]
data PatBuilder p
  = PatBuilderPat (Pat p)
  | PatBuilderPar (LHsToken "(" p) (LocatedA (PatBuilder p)) (LHsToken ")" p)
  | PatBuilderApp (LocatedA (PatBuilder p)) (LocatedA (PatBuilder p))
  | PatBuilderAppType (LocatedA (PatBuilder p)) (LHsToken "@" p) (HsPatSigType GhcPs)
  | PatBuilderOpApp (LocatedA (PatBuilder p)) (LocatedN RdrName)
                    (LocatedA (PatBuilder p)) (EpAnn [AddEpAnn])
  | PatBuilderVar (LocatedN RdrName)
  | PatBuilderOverLit (HsOverLit GhcPs)

instance Outputable (PatBuilder GhcPs) where
  ppr :: PatBuilder GhcPs -> SDoc
ppr (PatBuilderPat Pat GhcPs
p) = forall a. Outputable a => a -> SDoc
ppr Pat GhcPs
p
  ppr (PatBuilderPar LHsToken "(" GhcPs
_ (L SrcSpanAnnA
_ PatBuilder GhcPs
p) LHsToken ")" GhcPs
_) = forall doc. IsLine doc => doc -> doc
parens (forall a. Outputable a => a -> SDoc
ppr PatBuilder GhcPs
p)
  ppr (PatBuilderApp (L SrcSpanAnnA
_ PatBuilder GhcPs
p1) (L SrcSpanAnnA
_ PatBuilder GhcPs
p2)) = forall a. Outputable a => a -> SDoc
ppr PatBuilder GhcPs
p1 forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr PatBuilder GhcPs
p2
  ppr (PatBuilderAppType (L SrcSpanAnnA
_ PatBuilder GhcPs
p) LHsToken "@" GhcPs
_ HsPatSigType GhcPs
t) = forall a. Outputable a => a -> SDoc
ppr PatBuilder GhcPs
p forall doc. IsLine doc => doc -> doc -> doc
<+> forall doc. IsLine doc => String -> doc
text String
"@" forall doc. IsLine doc => doc -> doc -> doc
<> forall a. Outputable a => a -> SDoc
ppr HsPatSigType GhcPs
t
  ppr (PatBuilderOpApp (L SrcSpanAnnA
_ PatBuilder GhcPs
p1) LocatedN RdrName
op (L SrcSpanAnnA
_ PatBuilder GhcPs
p2) EpAnn [AddEpAnn]
_) = forall a. Outputable a => a -> SDoc
ppr PatBuilder GhcPs
p1 forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr LocatedN RdrName
op forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr PatBuilder GhcPs
p2
  ppr (PatBuilderVar LocatedN RdrName
v) = forall a. Outputable a => a -> SDoc
ppr LocatedN RdrName
v
  ppr (PatBuilderOverLit HsOverLit GhcPs
l) = forall a. Outputable a => a -> SDoc
ppr HsOverLit GhcPs
l

-- | An accumulator to build a prefix data constructor,
--   e.g. when parsing @MkT A B C@, the accumulator will evolve as follows:
--
--  @
--  1. PrefixDataConBuilder []        MkT
--  2. PrefixDataConBuilder [A]       MkT
--  3. PrefixDataConBuilder [A, B]    MkT
--  4. PrefixDataConBuilder [A, B, C] MkT
--  @
--
--  There are two reasons we have a separate builder type instead of using
--  @HsConDeclDetails GhcPs@ directly:
--
--  1. It's faster, because 'OrdList' gives us constant-time snoc.
--  2. Having a separate type helps ensure that we don't forget to finalize a
--     'RecTy' into a 'RecCon' (we do that in 'dataConBuilderDetails').
--
--  See Note [PatBuilder] for another builder type used in the parser.
--  Here the technique is similar, but the motivation is different.
data DataConBuilder
  = PrefixDataConBuilder
      (OrdList (LHsType GhcPs))  -- Data constructor fields
      (LocatedN RdrName)         -- Data constructor name
  | InfixDataConBuilder
      (LHsType GhcPs)    -- LHS field
      (LocatedN RdrName) -- Data constructor name
      (LHsType GhcPs)    -- RHS field

instance Outputable DataConBuilder where
  ppr :: DataConBuilder -> SDoc
ppr (PrefixDataConBuilder OrdList (LHsType GhcPs)
flds LocatedN RdrName
data_con) =
    SDoc -> Int -> SDoc -> SDoc
hang (forall a. Outputable a => a -> SDoc
ppr LocatedN RdrName
data_con) Int
2 (forall doc. IsLine doc => [doc] -> doc
sep (forall a b. (a -> b) -> [a] -> [b]
map forall a. Outputable a => a -> SDoc
ppr (forall (t :: * -> *) a. Foldable t => t a -> [a]
toList OrdList (LHsType GhcPs)
flds)))
  ppr (InfixDataConBuilder LHsType GhcPs
lhs LocatedN RdrName
data_con LHsType GhcPs
rhs) =
    forall a. Outputable a => a -> SDoc
ppr LHsType GhcPs
lhs forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr LocatedN RdrName
data_con forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr LHsType GhcPs
rhs

type instance Anno [LocatedA (StmtLR GhcPs GhcPs (LocatedA (PatBuilder GhcPs)))] = SrcSpanAnnL