-- | Output the raw Expr constructors. Helpful for writing pattern matching rewrites.
module Language.HERMIT.PrettyPrinter.GHC where

import Control.Arrow hiding ((<+>))

import Data.Char (isSpace)

import qualified GhcPlugins as GHC
import Language.HERMIT.Kure
import Language.HERMIT.PrettyPrinter

import Text.PrettyPrint.MarkedHughesPJ as PP

listify :: (MDoc a -> MDoc a -> MDoc a) -> [MDoc a] -> MDoc a
listify _  []     = text "[]"
listify op (d:ds) = op (text "[ " <> d) (foldr (\e es -> op (text ", " <> e) es) (text "]") ds)

-- | like vcat and hcat, only make the list syntax explicit
vlist, hlist :: [MDoc a] -> MDoc a
vlist = listify ($$)
hlist = listify (<+>)

corePrettyH :: PrettyOptions -> PrettyH Core
corePrettyH opts = do
    dynFlags <- constT GHC.getDynFlags

    let hideNotes = po_notes opts

        -- Use for any GHC structure, the 'showSDoc' prefix is to remind us
        -- that we are eliding infomation here.
        ppSDoc :: (GHC.Outputable a) => a -> MDoc b
        ppSDoc = toDoc . (if hideNotes then id else ("showSDoc: " ++)) . GHC.showSDoc dynFlags . GHC.ppr
            where toDoc s | any isSpace s = parens (text s)
                          | otherwise     = text s

        ppModGuts :: PrettyH GHC.ModGuts
        ppModGuts = arr (ppSDoc . GHC.mg_binds)

        ppProgram :: PrettyH GHC.CoreProgram
        ppProgram = arr ppSDoc

        ppCoreExpr :: PrettyH GHC.CoreExpr
        ppCoreExpr = arr ppSDoc

        ppCoreBind :: PrettyH GHC.CoreBind
        ppCoreBind = arr ppSDoc

        ppCoreAlt :: PrettyH GHC.CoreAlt
        ppCoreAlt = arr ppSDoc

        ppCoreDef :: PrettyH CoreDef
        ppCoreDef = defT ppCoreExpr $ \ i e -> ppSDoc i <> text "=" <> e

    promoteT (ppCoreExpr :: PrettyH GHC.CoreExpr)
     <+ promoteT (ppProgram  :: PrettyH GHC.CoreProgram)
     <+ promoteT (ppCoreBind :: PrettyH GHC.CoreBind)
     <+ promoteT (ppCoreDef  :: PrettyH CoreDef)
     <+ promoteT (ppModGuts  :: PrettyH GHC.ModGuts)
     <+ promoteT (ppCoreAlt  :: PrettyH GHC.CoreAlt)