From d3f6fdc3ea71386c2b9a9cd5a686455dbee3e60e Mon Sep 17 00:00:00 2001
From: Gregor Kleen <gkleen@yggdrasil.li>
Date: Mon, 21 May 2018 16:14:26 +0200
Subject: Introduce FSTs & Generalize input/output

`toFST` is currently invalid
---
 edit-lens/src/Data/String/DFST.hs | 42 ---------------------------------------
 1 file changed, 42 deletions(-)
 delete mode 100644 edit-lens/src/Data/String/DFST.hs

(limited to 'edit-lens/src/Data/String/DFST.hs')

diff --git a/edit-lens/src/Data/String/DFST.hs b/edit-lens/src/Data/String/DFST.hs
deleted file mode 100644
index 54a1336..0000000
--- a/edit-lens/src/Data/String/DFST.hs
+++ /dev/null
@@ -1,42 +0,0 @@
-{-# LANGUAGE ScopedTypeVariables
-#-}
-
-{-|
-Description: Deterministic finite state transducers
--}
-module Data.String.DFST
-  ( DFST(..)
-  , runDFST, runDFST'
-  ) where
-
-import Data.Map.Strict (Map, (!?))
-import qualified Data.Map.Strict as Map
-
-import Data.Set (Set)
-import qualified Data.Set as Set
-
-import Control.Monad
-
-data DFST state = DFST
-  { stInitial :: state
-  , stTransition :: Map (state, Char) (state, String)
-    -- ^ All @(s, c)@-combinations not mapped are assumed to map to @(s, Nothing)@
-  , stAccept :: Set state
-  }
-  
-runDFST :: forall state. Ord state => DFST state -> String -> Maybe String
-runDFST dfst@DFST{..} str = let (finalState, str') = runDFST' dfst stInitial str id
-                            in str' "" <$ guard (finalState `Set.member` stAccept)
-
-runDFST' :: forall state. Ord state
-         => DFST state
-         -> state -- ^ Current state
-         -> String -- ^ Remaining input
-         -> (String -> String) -- ^ Output as difference list
-         -> (state, (String -> String)) -- ^ Next state, altered output
-runDFST' _ st [] acc = (st, acc)
-runDFST' dfst@DFST{..} st (c:cs) acc
-  | Just (st', mc') <- stTransition !? (st, c)
-  = runDFST' dfst st' cs $ acc . (mc' ++)
-  | otherwise
-  = runDFST' dfst st cs acc
-- 
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