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-rw-r--r--src/Grasp/Parser.hs99
1 files changed, 99 insertions, 0 deletions
diff --git a/src/Grasp/Parser.hs b/src/Grasp/Parser.hs
new file mode 100644
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--- /dev/null
+++ b/src/Grasp/Parser.hs
@@ -0,0 +1,99 @@
+module Grasp.Parser (
+ GraspProgram(..),
+ parseGrasp
+ ) where
+
+
+import Control.Applicative( some )
+import Text.ParserCombinators.Parsec
+import Data.Graph.Inductive.Graph( Node, LNode, LEdge, (&) )
+import Data.Graph.Inductive.Graph as Graph
+import Data.Graph.Inductive.Tree
+
+
+
+
+data GraspProgram = Gr String String
+
+
+
+
+parseGrasp :: String -> Either ParseError ([LNode String],[LEdge String])
+parseGrasp = parse grasp "error"
+--parseGrasp input =
+-- let firstPass = parse grasp "error" input
+-- in case firstPass of
+-- Left e -> Left e
+-- Right (n,e) -> validate n e
+
+
+
+--validate :: [LNode String] -> [LEdge String] -> Either ParseError GraspProgram
+
+
+
+
+grasp = do
+ string "digraph {"
+ whiteSpace
+ n <- many node
+ e <- many edge
+ string "}"
+ eol
+ eof
+ return (n,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"
+