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module Grasp.Parser (
GraspProgram(..),
parseGrasp,
dup
) where
import Control.Applicative( some )
import Text.ParserCombinators.Parsec
import Text.ParserCombinators.Parsec.Error
import Text.Parsec.Pos
import Text.Read( readMaybe )
import Data.Graph.Inductive.Graph( Node, LNode, LEdge, (&) )
import Data.Graph.Inductive.Graph as Graph
import Data.Graph.Inductive.Tree
import Data.List
import Data.Maybe
type GraspProgram = Gr String String
type StrLNode a = (String,a)
type StrLEdge a = (String,String,a)
parseGrasp :: String -> Either ParseError GraspProgram
parseGrasp input =
parse grasp "error" input >>= sanityCheck >>= nameCheck >>= return . constructGraph
sanityCheck :: ([LNode String],[LEdge String]) -> Either ParseError ([LNode String],[LEdge String])
sanityCheck (nodeList, edgeList) = Right (nodeList, edgeList)
nameCheck :: ([LNode String],[LEdge String]) -> Either ParseError ([LNode String],[LEdge String])
nameCheck (nodeList, edgeList) =
let nameEdges = filter (\(_,_,z) -> z == "name") edgeList
-- designed to convert the edges into (lnode,name) pairs
findNode n l = find (\(x,_) -> x == n) l
mapFunc (x,y,_) = (fromJust (findNode x nodeList), snd . fromJust $ (findNode y nodeList))
namedNodes = map mapFunc nameEdges
a = multiNames namedNodes
b = nonStringNames namedNodes
c = graspMainPresent namedNodes
in case (a,b,c) of
(Just x,_,_) -> Left (newErrorMessage (Message ("node " ++ (show x) ++ " has multiple names")) (newPos "" 0 0))
(_,Just x,_) -> Left (newErrorMessage (Message ("node " ++ (show x) ++ " has a numeric name")) (newPos "" 0 0))
(_,_,False) -> Left (newErrorMessage (Message "could not find grasp:main") (newPos "" 0 0))
(_,_,_) -> Right (nodeList, edgeList)
multiNames :: [(LNode String, String)] -> Maybe (LNode String)
multiNames = dup . (map fst)
nonStringNames :: [(LNode String, String)] -> Maybe (LNode String)
nonStringNames nodeList =
let f x = readMaybe x :: Maybe Float
nonStringNames = filter (isJust . f . snd) nodeList
in if (nonStringNames == []) then Nothing else Just (fst . head $ nonStringNames)
graspMainPresent :: [(LNode String, String)] -> Bool
graspMainPresent = any (\x -> snd x == "grasp:main")
constructGraph :: ([LNode String],[LEdge String]) -> GraspProgram
constructGraph = uncurry Graph.mkGraph
dup :: (Eq a) => [a] -> Maybe a
dup x =
let dup' [] _ = Nothing
dup' (x:xs) s = if (x `elem` s) then Just x else dup' xs (x:s)
in dup' x []
grasp = do
string "digraph {"
whiteSpace
(n,e) <- stmtList ([],[])
string "}"
eol
eof
return (n,e)
stmtList (n,e) =
try (node >>= (\x -> stmtList (x:n,e)) )
<|> try (edge >>= (\x -> stmtList (n,x:e)) )
<|> return (reverse n, reverse e)
node = do
i <- ident
l <- labelAttrib
whiteSpace
return (i,l)
edge = do
a <- ident
directedEdge
b <- ident
l <- labelAttrib
whiteSpace
return (a,b,l)
ident = do
d <- some digit
inLineWhSp
return (read d)
labelAttrib = do
char '['
inLineWhSp
string "label=\""
l <- labelID
char '\"'
inLineWhSp
string "];"
return l
labelID = some (noneOf "\"\r\n\\" <|> escapedChar)
escapedChar = try (string "\\\"" >> return '\"')
<|> try (string "\\\\" >> return '\\')
directedEdge = string "->" >> inLineWhSp
inLineWhSp = many (oneOf "\t ")
whiteSpace = many (oneOf "\n\r\t ")
eol = try (string "\r\n")
<|> try (string "\n\r")
<|> try (string "\n")
<|> try (string "\r")
<?> "end of line"
|