81 lines
2.5 KiB
Standard ML
81 lines
2.5 KiB
Standard ML
signature MAKE_DFA_LOOP =
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sig
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val fStart: int * int * string * string list * Word8.word * int -> int
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val startState: Word8.word
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end
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functor MakeNextDfaLoop(M: MAKE_DFA_LOOP) =
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struct
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fun next (lineGap: LineGap.t, cursorIdx) =
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let
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val {rightStrings, idx = bufferIdx, ...} = lineGap
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(* convert absolute cursorIdx to idx relative to hd string *)
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val strIdx = cursorIdx - bufferIdx
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in
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case rightStrings of
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shd :: stl =>
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if strIdx < String.size shd then
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(* strIdx is in this string *)
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M.fStart (strIdx, cursorIdx, shd, stl, M.startState, 1)
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else
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(* strIdx is in tl *)
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(case stl of
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stlhd :: stltl =>
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let val strIdx = strIdx - String.size shd
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in M.fStart (strIdx, cursorIdx, stlhd, stltl, M.startState, 1)
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end
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| _ => cursorIdx)
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| [] => cursorIdx
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end
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end
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functor MakePrevDfaLoop(M: MAKE_DFA_LOOP) =
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struct
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fun prev (lineGap: LineGap.t, cursorIdx) =
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let
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val {rightStrings, leftStrings, idx = bufferIdx, ...} = lineGap
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(* convert absolute cursorIdx to idx relative to hd string *)
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val strIdx = cursorIdx - bufferIdx
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in
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case rightStrings of
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shd :: stl =>
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if strIdx < String.size shd then
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(* strIdx is in this string *)
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M.fStart (strIdx, cursorIdx, shd, leftStrings, M.startState, 1)
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else
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(* strIdx is in tl *)
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(case stl of
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stlhd :: stltl =>
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let
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val strIdx = strIdx - String.size shd
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val leftStrings = shd :: leftStrings
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in
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M.fStart
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(strIdx, cursorIdx, stlhd, leftStrings, M.startState, 1)
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end
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| [] => cursorIdx)
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| [] => cursorIdx
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end
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end
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functor MakePrevDfaLoopMinus1(M: MAKE_DFA_LOOP) =
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struct
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fun prev (lineGap: LineGap.t, cursorIdx) =
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let
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val {idx = bufferIdx, leftStrings, ...} = lineGap
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val strIdx = cursorIdx - bufferIdx - 1
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val absIdx = cursorIdx - 1
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in
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if strIdx < 0 then
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case leftStrings of
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lhd :: ltl =>
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M.fStart (String.size lhd - 1, absIdx, lhd, ltl, M.startState, 1)
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| [] => 0
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else
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case #rightStrings lineGap of
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rhd :: _ =>
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M.fStart (strIdx, absIdx, rhd, leftStrings, M.startState, 1)
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| [] => Int.max (0, cursorIdx - 2)
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end
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end
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