{-# LANGUAGE CPP #-}
#if __GLASGOW_HASKELL__ <= 708
{-# LANGUAGE OverlappingInstances #-}
#endif
{-# LANGUAGE FlexibleInstances #-}
{-# OPTIONS_GHC -fno-warn-incomplete-patterns #-}

-- | Pretty-printer for BNFC.
--   Generated by the BNF converter.

module BNFC.Print where

import qualified BNFC.Abs
import Data.Char

-- | The top-level printing method.

printTree :: Print a => a -> String
printTree = render . prt 0

type Doc = [ShowS] -> [ShowS]

doc :: ShowS -> Doc
doc = (:)

render :: Doc -> String
render d = rend 0 (map ($ "") $ d []) "" where
  rend i ss = case ss of
    "["      :ts -> showChar '[' . rend i ts
    "("      :ts -> showChar '(' . rend i ts
    "{"      :ts -> showChar '{' . new (i+1) . rend (i+1) ts
    "}" : ";":ts -> new (i-1) . space "}" . showChar ';' . new (i-1) . rend (i-1) ts
    "}"      :ts -> new (i-1) . showChar '}' . new (i-1) . rend (i-1) ts
    [";"]        -> showChar ';'
    ";"      :ts -> showChar ';' . new i . rend i ts
    t  : ts@(p:_) | closingOrPunctuation p -> showString t . rend i ts
    t        :ts -> space t . rend i ts
    _            -> id
  new i     = showChar '\n' . replicateS (2*i) (showChar ' ') . dropWhile isSpace
  space t s =
    case (all isSpace t', null spc, null rest) of
      (True , _   , True ) -> []              -- remove trailing space
      (False, _   , True ) -> t'              -- remove trailing space
      (False, True, False) -> t' ++ ' ' : s   -- add space if none
      _                    -> t' ++ s
    where
      t'          = showString t []
      (spc, rest) = span isSpace s

  closingOrPunctuation :: String -> Bool
  closingOrPunctuation [c] = c `elem` closerOrPunct
  closingOrPunctuation _   = False

  closerOrPunct :: String
  closerOrPunct = ")],;"

parenth :: Doc -> Doc
parenth ss = doc (showChar '(') . ss . doc (showChar ')')

concatS :: [ShowS] -> ShowS
concatS = foldr (.) id

concatD :: [Doc] -> Doc
concatD = foldr (.) id

replicateS :: Int -> ShowS -> ShowS
replicateS n f = concatS (replicate n f)

-- | The printer class does the job.

class Print a where
  prt :: Int -> a -> Doc
  prtList :: Int -> [a] -> Doc
  prtList i = concatD . map (prt i)

instance {-# OVERLAPPABLE #-} Print a => Print [a] where
  prt = prtList

instance Print Char where
  prt _ s = doc (showChar '\'' . mkEsc '\'' s . showChar '\'')
  prtList _ s = doc (showChar '"' . concatS (map (mkEsc '"') s) . showChar '"')

mkEsc :: Char -> Char -> ShowS
mkEsc q s = case s of
  _ | s == q -> showChar '\\' . showChar s
  '\\'-> showString "\\\\"
  '\n' -> showString "\\n"
  '\t' -> showString "\\t"
  _ -> showChar s

prPrec :: Int -> Int -> Doc -> Doc
prPrec i j = if j < i then parenth else id

instance Print Integer where
  prt _ x = doc (shows x)

instance Print Double where
  prt _ x = doc (shows x)

instance Print BNFC.Abs.Identifier where
  prt _ (BNFC.Abs.Identifier (_,i)) = doc $ showString $ i

instance Print BNFC.Abs.Grammar where
  prt i e = case e of
    BNFC.Abs.Grammar defs -> prPrec i 0 (concatD [prt 0 defs])

instance Print [BNFC.Abs.Def] where
  prt = prtList

instance Print BNFC.Abs.Def where
  prt i e = case e of
    BNFC.Abs.Rule label cat items -> prPrec i 0 (concatD [prt 0 label, doc (showString "."), prt 0 cat, doc (showString "::="), prt 0 items])
    BNFC.Abs.Comment str -> prPrec i 0 (concatD [doc (showString "comment"), prt 0 str])
    BNFC.Abs.Comments str1 str2 -> prPrec i 0 (concatD [doc (showString "comment"), prt 0 str1, prt 0 str2])
    BNFC.Abs.Internal label cat items -> prPrec i 0 (concatD [doc (showString "internal"), prt 0 label, doc (showString "."), prt 0 cat, doc (showString "::="), prt 0 items])
    BNFC.Abs.Token identifier reg -> prPrec i 0 (concatD [doc (showString "token"), prt 0 identifier, prt 0 reg])
    BNFC.Abs.PosToken identifier reg -> prPrec i 0 (concatD [doc (showString "position"), doc (showString "token"), prt 0 identifier, prt 0 reg])
    BNFC.Abs.Entryp cats -> prPrec i 0 (concatD [doc (showString "entrypoints"), prt 0 cats])
    BNFC.Abs.Separator minimumsize cat str -> prPrec i 0 (concatD [doc (showString "separator"), prt 0 minimumsize, prt 0 cat, prt 0 str])
    BNFC.Abs.Terminator minimumsize cat str -> prPrec i 0 (concatD [doc (showString "terminator"), prt 0 minimumsize, prt 0 cat, prt 0 str])
    BNFC.Abs.Delimiters cat str1 str2 separation minimumsize -> prPrec i 0 (concatD [doc (showString "delimiters"), prt 0 cat, prt 0 str1, prt 0 str2, prt 0 separation, prt 0 minimumsize])
    BNFC.Abs.Coercions identifier n -> prPrec i 0 (concatD [doc (showString "coercions"), prt 0 identifier, prt 0 n])
    BNFC.Abs.Rules identifier rhss -> prPrec i 0 (concatD [doc (showString "rules"), prt 0 identifier, doc (showString "::="), prt 0 rhss])
    BNFC.Abs.Function identifier args exp -> prPrec i 0 (concatD [doc (showString "define"), prt 0 identifier, prt 0 args, doc (showString "="), prt 0 exp])
    BNFC.Abs.Layout strs -> prPrec i 0 (concatD [doc (showString "layout"), prt 0 strs])
    BNFC.Abs.LayoutStop strs -> prPrec i 0 (concatD [doc (showString "layout"), doc (showString "stop"), prt 0 strs])
    BNFC.Abs.LayoutTop -> prPrec i 0 (concatD [doc (showString "layout"), doc (showString "toplevel")])
  prtList _ [] = concatD []
  prtList _ [x] = concatD [prt 0 x]

  prtList _ (x:xs) = concatD [prt 0 x, doc (showString ";"), prt 0 xs]

instance Print BNFC.Abs.Item where
  prt i e = case e of
    BNFC.Abs.Terminal str -> prPrec i 0 (concatD [prt 0 str])
    BNFC.Abs.NTerminal cat -> prPrec i 0 (concatD [prt 0 cat])
  prtList _ [] = concatD []
  prtList _ (x:xs) = concatD [prt 0 x, prt 0 xs]

instance Print [BNFC.Abs.Item] where
  prt = prtList

instance Print BNFC.Abs.Cat where
  prt i e = case e of
    BNFC.Abs.ListCat cat -> prPrec i 0 (concatD [doc (showString "["), prt 0 cat, doc (showString "]")])
    BNFC.Abs.IdCat identifier -> prPrec i 0 (concatD [prt 0 identifier])
  prtList _ [] = concatD []
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, doc (showString ","), prt 0 xs]

instance Print [BNFC.Abs.Cat] where
  prt = prtList

instance Print BNFC.Abs.Label where
  prt i e = case e of
    BNFC.Abs.Id identifier -> prPrec i 0 (concatD [prt 0 identifier])
    BNFC.Abs.Wild -> prPrec i 0 (concatD [doc (showString "_")])
    BNFC.Abs.ListE -> prPrec i 0 (concatD [doc (showString "["), doc (showString "]")])
    BNFC.Abs.ListCons -> prPrec i 0 (concatD [doc (showString "("), doc (showString ":"), doc (showString ")")])
    BNFC.Abs.ListOne -> prPrec i 0 (concatD [doc (showString "("), doc (showString ":"), doc (showString "["), doc (showString "]"), doc (showString ")")])

instance Print BNFC.Abs.Arg where
  prt i e = case e of
    BNFC.Abs.Arg identifier -> prPrec i 0 (concatD [prt 0 identifier])
  prtList _ [] = concatD []
  prtList _ (x:xs) = concatD [prt 0 x, prt 0 xs]

instance Print [BNFC.Abs.Arg] where
  prt = prtList

instance Print BNFC.Abs.Separation where
  prt i e = case e of
    BNFC.Abs.SepNone -> prPrec i 0 (concatD [])
    BNFC.Abs.SepTerm str -> prPrec i 0 (concatD [doc (showString "terminator"), prt 0 str])
    BNFC.Abs.SepSepar str -> prPrec i 0 (concatD [doc (showString "separator"), prt 0 str])

instance Print [String] where
  prt = prtList

instance Print BNFC.Abs.Exp where
  prt i e = case e of
    BNFC.Abs.Cons exp1 exp2 -> prPrec i 0 (concatD [prt 1 exp1, doc (showString ":"), prt 0 exp2])
    BNFC.Abs.App identifier exps -> prPrec i 1 (concatD [prt 0 identifier, prt 2 exps])
    BNFC.Abs.Var identifier -> prPrec i 2 (concatD [prt 0 identifier])
    BNFC.Abs.LitInt n -> prPrec i 2 (concatD [prt 0 n])
    BNFC.Abs.LitChar c -> prPrec i 2 (concatD [prt 0 c])
    BNFC.Abs.LitString str -> prPrec i 2 (concatD [prt 0 str])
    BNFC.Abs.LitDouble d -> prPrec i 2 (concatD [prt 0 d])
    BNFC.Abs.List exps -> prPrec i 2 (concatD [doc (showString "["), prt 0 exps, doc (showString "]")])
  prtList 2 [x] = concatD [prt 2 x]
  prtList 2 (x:xs) = concatD [prt 2 x, prt 2 xs]
  prtList _ [] = concatD []
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, doc (showString ","), prt 0 xs]

instance Print [BNFC.Abs.Exp] where
  prt = prtList

instance Print BNFC.Abs.RHS where
  prt i e = case e of
    BNFC.Abs.RHS items -> prPrec i 0 (concatD [prt 0 items])
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, doc (showString "|"), prt 0 xs]

instance Print [BNFC.Abs.RHS] where
  prt = prtList

instance Print BNFC.Abs.MinimumSize where
  prt i e = case e of
    BNFC.Abs.MNonempty -> prPrec i 0 (concatD [doc (showString "nonempty")])
    BNFC.Abs.MEmpty -> prPrec i 0 (concatD [])

instance Print BNFC.Abs.Reg where
  prt i e = case e of
    BNFC.Abs.RAlt reg1 reg2 -> prPrec i 0 (concatD [prt 0 reg1, doc (showString "|"), prt 1 reg2])
    BNFC.Abs.RMinus reg1 reg2 -> prPrec i 1 (concatD [prt 1 reg1, doc (showString "-"), prt 2 reg2])
    BNFC.Abs.RSeq reg1 reg2 -> prPrec i 2 (concatD [prt 2 reg1, prt 3 reg2])
    BNFC.Abs.RStar reg -> prPrec i 3 (concatD [prt 3 reg, doc (showString "*")])
    BNFC.Abs.RPlus reg -> prPrec i 3 (concatD [prt 3 reg, doc (showString "+")])
    BNFC.Abs.ROpt reg -> prPrec i 3 (concatD [prt 3 reg, doc (showString "?")])
    BNFC.Abs.REps -> prPrec i 3 (concatD [doc (showString "eps")])
    BNFC.Abs.RChar c -> prPrec i 3 (concatD [prt 0 c])
    BNFC.Abs.RAlts str -> prPrec i 3 (concatD [doc (showString "["), prt 0 str, doc (showString "]")])
    BNFC.Abs.RSeqs str -> prPrec i 3 (concatD [doc (showString "{"), prt 0 str, doc (showString "}")])
    BNFC.Abs.RDigit -> prPrec i 3 (concatD [doc (showString "digit")])
    BNFC.Abs.RLetter -> prPrec i 3 (concatD [doc (showString "letter")])
    BNFC.Abs.RUpper -> prPrec i 3 (concatD [doc (showString "upper")])
    BNFC.Abs.RLower -> prPrec i 3 (concatD [doc (showString "lower")])
    BNFC.Abs.RAny -> prPrec i 3 (concatD [doc (showString "char")])