{-# OPTIONS_GHC -fno-warn-incomplete-patterns #-}
module PrintBNF where

-- pretty-printer generated by the BNF converter

import AbsBNF
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
    ";"      :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 = showString t . (\s -> if null s then "" else ' ':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 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 Ident where
  prt _ (Ident i) = doc (showString i)
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, doc (showString ","), prt 0 xs]

instance Print LGrammar where
  prt i e = case e of
    LGr ldefs -> prPrec i 0 (concatD [prt 0 ldefs])

instance Print LDef where
  prt i e = case e of
    DefAll def -> prPrec i 0 (concatD [prt 0 def])
    DefSome ids def -> prPrec i 0 (concatD [prt 0 ids, doc (showString ":"), prt 0 def])
    LDefView ids -> prPrec i 0 (concatD [doc (showString "views"), prt 0 ids])
  prtList _ [] = concatD []
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, doc (showString ";"), prt 0 xs]
instance Print Grammar where
  prt i e = case e of
    Grammar defs -> prPrec i 0 (concatD [prt 0 defs])

instance Print Def where
  prt i e = case e of
    Rule label cat items -> prPrec i 0 (concatD [prt 0 label, doc (showString "."), prt 0 cat, doc (showString "::="), prt 0 items])
    Comment str -> prPrec i 0 (concatD [doc (showString "comment"), prt 0 str])
    Comments str1 str2 -> prPrec i 0 (concatD [doc (showString "comment"), prt 0 str1, prt 0 str2])
    Internal label cat items -> prPrec i 0 (concatD [doc (showString "internal"), prt 0 label, doc (showString "."), prt 0 cat, doc (showString "::="), prt 0 items])
    Token id reg -> prPrec i 0 (concatD [doc (showString "token"), prt 0 id, prt 0 reg])
    PosToken id reg -> prPrec i 0 (concatD [doc (showString "position"), doc (showString "token"), prt 0 id, prt 0 reg])
    Entryp ids -> prPrec i 0 (concatD [doc (showString "entrypoints"), prt 0 ids])
    Separator minimumsize cat str -> prPrec i 0 (concatD [doc (showString "separator"), prt 0 minimumsize, prt 0 cat, prt 0 str])
    Terminator minimumsize cat str -> prPrec i 0 (concatD [doc (showString "terminator"), prt 0 minimumsize, prt 0 cat, prt 0 str])
    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])
    Coercions id n -> prPrec i 0 (concatD [doc (showString "coercions"), prt 0 id, prt 0 n])
    Rules id rhss -> prPrec i 0 (concatD [doc (showString "rules"), prt 0 id, doc (showString "::="), prt 0 rhss])
    Function id args exp -> prPrec i 0 (concatD [doc (showString "define"), prt 0 id, prt 0 args, doc (showString "="), prt 0 exp])
    Layout strs -> prPrec i 0 (concatD [doc (showString "layout"), prt 0 strs])
    LayoutStop strs -> prPrec i 0 (concatD [doc (showString "layout"), doc (showString "stop"), prt 0 strs])
    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 Item where
  prt i e = case e of
    Terminal str -> prPrec i 0 (concatD [prt 0 str])
    NTerminal cat -> prPrec i 0 (concatD [prt 0 cat])
  prtList _ [] = concatD []
  prtList _ (x:xs) = concatD [prt 0 x, prt 0 xs]
instance Print Cat where
  prt i e = case e of
    ListCat cat -> prPrec i 0 (concatD [doc (showString "["), prt 0 cat, doc (showString "]")])
    IdCat id -> prPrec i 0 (concatD [prt 0 id])

instance Print Label where
  prt i e = case e of
    LabNoP labelid -> prPrec i 0 (concatD [prt 0 labelid])
    LabP labelid profitems -> prPrec i 0 (concatD [prt 0 labelid, prt 0 profitems])
    LabPF labelid1 labelid2 profitems -> prPrec i 0 (concatD [prt 0 labelid1, prt 0 labelid2, prt 0 profitems])
    LabF labelid1 labelid2 -> prPrec i 0 (concatD [prt 0 labelid1, prt 0 labelid2])

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

instance Print ProfItem where
  prt i e = case e of
    ProfIt intlists ns -> prPrec i 0 (concatD [doc (showString "("), doc (showString "["), prt 0 intlists, doc (showString "]"), doc (showString ","), doc (showString "["), prt 0 ns, doc (showString "]"), doc (showString ")")])
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, prt 0 xs]
instance Print IntList where
  prt i e = case e of
    Ints ns -> prPrec i 0 (concatD [doc (showString "["), prt 0 ns, doc (showString "]")])
  prtList _ [] = concatD []
  prtList _ [x] = concatD [prt 0 x]
  prtList _ (x:xs) = concatD [prt 0 x, doc (showString ","), prt 0 xs]
instance Print Arg where
  prt i e = case e of
    Arg id -> prPrec i 0 (concatD [prt 0 id])
  prtList _ [] = concatD []
  prtList _ (x:xs) = concatD [prt 0 x, prt 0 xs]
instance Print Separation where
  prt i e = case e of
    SepNone -> prPrec i 0 (concatD [])
    SepTerm str -> prPrec i 0 (concatD [doc (showString "terminator"), prt 0 str])
    SepSepar str -> prPrec i 0 (concatD [doc (showString "separator"), prt 0 str])

instance Print Exp where
  prt i e = case e of
    Cons exp1 exp2 -> prPrec i 0 (concatD [prt 1 exp1, doc (showString ":"), prt 0 exp2])
    App id exps -> prPrec i 1 (concatD [prt 0 id, prt 2 exps])
    Var id -> prPrec i 2 (concatD [prt 0 id])
    LitInt n -> prPrec i 2 (concatD [prt 0 n])
    LitChar c -> prPrec i 2 (concatD [prt 0 c])
    LitString str -> prPrec i 2 (concatD [prt 0 str])
    LitDouble d -> prPrec i 2 (concatD [prt 0 d])
    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 RHS where
  prt i e = case e of
    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 MinimumSize where
  prt i e = case e of
    MNonempty -> prPrec i 0 (concatD [doc (showString "nonempty")])
    MEmpty -> prPrec i 0 (concatD [])

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