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refactor Cursor.viH to use DFA

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This commit is contained in:
Humza Shahid
2025-09-17 10:45:37 +01:00
parent 9ddb5f68d7
commit dbf05ec8dc
5 changed files with 63 additions and 79 deletions
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62
fcore/cursor-dfa/vi-l-dfa.sml
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@@ -4,19 +4,30 @@ struct
val notNewlineState: Word8.word = 0w1
val oneNewlineState: Word8.word = 0w2
val twoNewlineState: Word8.word = 0w3
val notNewlineAfterNewlineState: Word8.word = 0w4
fun makeStart i =
if Char.chr i = #"\n" then oneNewlineState else notNewlineState
fun makeOneNewline i =
if Char.chr i = #"\n" then twoNewlineState else notNewlineState
if Char.chr i = #"\n" then twoNewlineState else notNewlineAfterNewlineState
fun makeTwoNeline i =
if Char.chr i = #"\n" then oneNewlineState else notNewlineAfterNewlineState
val startTable = Vector.tabulate (255, makeStart)
val notNewlineTable = startTable
val oneNewlineTable = Vector.tabulate (255, makeOneNewline)
val twoNewLineTable = startTable
val notNewlineAfterNewlineTable = notNewlineTable
val tables = #[startTable, notNewlineTable, oneNewlineTable, twoNewLineTable]
val tables =
#[ startTable
, notNewlineTable
, oneNewlineTable
, twoNewLineTable
, notNewlineAfterNewlineTable
]
fun next (currentState, chr) =
let val table = Vector.sub (tables, Word8.toInt currentState)
@@ -38,12 +49,17 @@ struct
val chr = String.sub (str, idx)
val newState = next (currentState, chr)
in
if newState = twoNewlineState then
if
newState = twoNewlineState
then
if counter - 1 = ~1 then
absIdx - 1
else
loop (idx + 1, absIdx + 1, str, tl, startState, counter - 1)
else if newState = notNewlineState then
else if
newState = notNewlineState
orelse newState = notNewlineAfterNewlineState
then
if counter - 1 = ~1 then
absIdx
else
@@ -55,5 +71,43 @@ struct
val fStart = loop
end)
structure ViH =
MakePrevDfaLoop
(struct
val startState = startState
fun loop (idx, absIdx, str, tl, currentState, counter) =
if idx < 0 then
case tl of
str :: tl =>
loop
(String.size str - 1, absIdx, str, tl, currentState, counter)
| [] => absIdx
else
let
val chr = String.sub (str, idx)
val newState = next (currentState, chr)
in
if newState = twoNewlineState then
if counter - 1 = ~1 then absIdx
else loop (idx - 1, absIdx - 1, str, tl, newState, counter - 1)
else if newState = notNewlineState then
if counter - 1 = ~1 then
absIdx
else
loop (idx - 1, absIdx - 1, str, tl, startState, counter - 1)
else if newState = notNewlineAfterNewlineState then
if counter - 1 <= 0 then
absIdx
else
loop (idx - 1, absIdx - 1, str, tl, startState, counter - 1)
else
loop (idx - 1, absIdx - 1, str, tl, newState, counter)
end
val fStart = loop
end)
val next = ViL.next
val prev = ViH.prev
end