Parser for Grasp begun, using a subset of the graphviz DOT language

1 files changed, 99 insertions, 0 deletions

diff --git a/src/Grasp/Parser.hs b/src/Grasp/Parser.hs
new file mode 100644
index 0000000..3a71fdf
--- /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"
+