parserParser/test.icl

   1 module test
   2
   3 import StdEnv
   4
   5 import Data.Functor
   6 import Control.Applicative
   7 import Control.Monad
   8 import Control.Monad.State
   9
  10 import Text.Parsers.Simple.Core
  11
  12 :: In a b = (:.) infix 0 a b
  13
  14 :: Gram
  15         = Def (Gram -> In Gram Gram)
  16         | Def2 ((Gram,Gram) -> In (Gram, Gram) Gram)
  17         | Lit String
  18         | Int
  19         | (-.) infixr 2 Gram Gram
  20         | (|.) infix 1 Gram Gram
  21 :: Gast
  22         = INT Int
  23         | LIT String
  24         | BIN Gast Gast
  25
  26 parseFromGram :: Gram -> Parser String Gast
  27 parseFromGram (Def g)  = let (body :. gram) = g body in parseFromGram gram
  28 parseFromGram  Int     = INT o toInt <$> pSatisfy (\s->toString (toInt s) == s)
  29 parseFromGram (Lit i)  = LIT <$> pSatisfy ((==)i)
  30 parseFromGram (a -. b) = BIN <$> parseFromGram a <*> parseFromGram b
  31 parseFromGram (a |. b) = parseFromGram a <|> parseFromGram b
  32
  33 //Start = runParser (parseFromGram gram) [".","."]
  34 Start = parse (parseFromGram gram) ["5"]
  35 where
  36         gram =
  37                 Def \lit =  Int
  38                          |. Lit "(" -. expr -. Lit ")"
  39                 Def \fac =  lit -. Lit "*" -. fac
  40                          |. lit -. Lit "/" -. fac
  41                          |. lit :.
  42                 Def \expr=  fac -. Lit "+" -. expr
  43                          |. fac -. Lit "-" -. expr
  44                          |. fac :.
  45                 expr