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37 lines
1.1 KiB
Idris
37 lines
1.1 KiB
Idris
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module System.REPL
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import System.File
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||| A basic read-eval-print loop, maintaining a state
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||| @ state the input state
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||| @ prompt the prompt to show
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||| @ onInput the function to run on reading input, returning a String to
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||| output and a new state. Returns Nothing if the repl should exit
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export
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replWith : (state : a) -> (prompt : String) ->
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(onInput : a -> String -> Maybe (String, a)) -> IO ()
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replWith acc prompt fn
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= do eof <- fEOF stdin
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if eof
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then pure ()
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else do putStr prompt
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fflush stdout
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x <- getLine
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case fn acc x of
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Just (out, acc') =>
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do putStr out
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replWith acc' prompt fn
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Nothing => pure ()
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||| A basic read-eval-print loop
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export
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repl : (prompt : String) ->
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(onInput : String -> String) -> IO ()
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repl prompt fn
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= replWith () prompt (\x, s => Just (fn s, ()))
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