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import Text.Combinators.Parsec
data ThueProgram = ThueProgram { substitutionRules :: [Rule]
, initialState :: State }
deriving (Show)
data Rule = Rule { original :: State
, replacement :: State }
deriving (Show)
type State = String
parseThue :: String -> Either ParseError ThueProgram
parseThue = parse thue "error"
thue = do
rs <- many ruleLine
separatorLine
i <- stateLine
return (ThueProgram rs i)
ruleLine = do
r <- rule
eol
return r
rule = do
o <- state
separator
r <- state
return (Rule o r)
separatorLine = separator >> eol
separator = string "::="
stateLine = do
s <- state
eol
return s
state =
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