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module turinglog
import StdEnv
import TuringMachines
Start :: *World -> *World
Start w
# (io,w) = stdio w
# m = initTuringMachine machine tape
# io = fwrites (toString m +++ "\n") io
# io = loop m io
# (ok,w) = fclose io w
| not ok = abort "Couldn't close stdio\n"
| otherwise = w
where
loop m f
# m = step m
# f = fwrites (toString m +++ "\n") f
| m.running == Running = loop m f
| otherwise = f
tape :: Tape Char
tape = [Just c \\ c <- fromString "abbaba"]
machine :: TuringMachine Char
machine = { alphabet = ['a', 'b'],
inputs = ['a', 'b'],
transition = f }
where
f :: Int (Maybe Char) -> TuringMachineMove Char
f 0 Nothing = Step 1 Nothing Right
f 1 Nothing = Step 2 Nothing Left
f 1 (Just 'a') = Step 1 (Just 'b') Right
f 1 (Just 'b') = Step 1 (Just 'a') Right
f 2 (Just 'a') = Step 2 (Just 'a') Left
f 2 (Just 'b') = Step 2 (Just 'b') Left
f _ _ = Halt
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