module PrintNFAe ()
where
import PP
import NFAe
import qualified Text.PrettyPrint.HughesPJ as PP
import Text.PrettyPrint.HughesPJ(Doc,text,char,int,(<>),(<+>),($+$),($$),render,nest,vcat)
import Graphviz

instance (PP q, PP s) => PP (NFAe q s)
   where pp (NFAe { states = q,
                    symbols = sigma,
                    delta = d,
                    start = q0,
                    final = f}) 
             = text "NFAe" $$ nest 5 (vcat [text "Q"     $$ (nest 7 $ set q),
                                            text "Sigma" $$ (nest 7 $ set sigma),
                                            text "Delta" $$ (nest 7 $ graph q sigma d), 
                                            text "q0"    $$ (nest 7 $ pp q0),
                                            text "F"     $$ (nest 7 $ set f)
                                           ])

graph q sigma d = vcat $ [ (pp p) <+> (pp a) <+> text "->" <+> (set (d p (Just a)))
                               | p <- q, a <- sigma] ++ 
                         [ (pp p) <+> text "epsilon ->" <+> (set (d p Nothing))
                               | p <- q]

instance (PP q, PP s) => Show (NFAe q s)
  where show = render . pp
------------------------------------------------
-- class instance for graphviz drawing.
-- e.g.    pnG ma      opens a window with a picture of ma

instance (Eq q,Show q,Show s) => Graph (NFAe q s) where
  nodes t = map f pairs
    where pairs = zip (states t) [0..] 
          f (q,n) = (n,show q,stateColor t q)
          stateColor t q | q == (start t)   = Green
	  stateColor t q | elem q (final t) = Red
	  stateColor t q                    = None
	                            
 

  edges t = [(n,m,sh s,None) 
            | (q1,n) <- pairs
            , s <- Nothing : (map Just (symbols t))
            , m <- locate q1 s ]
    where pairs = zip (states t) [0..]
          find q = case lookup q pairs of {Just n -> n}
          locate q1 s = map find (delta t q1 s) 
          sh Nothing = "^"
          sh (Just z) = show z