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fix bugs in implementation for 'Nfa.getMatchesInRange'

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This commit is contained in:
Humza Shahid
2025-09-29 22:57:19 +01:00
parent d37e510b24
commit b35d045a09
2 changed files with 19 additions and 170 deletions
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187
fcore/search-list/nfa.sml
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@@ -169,194 +169,43 @@ struct
end
local
fun backtrackRange
(hd, tl, prevStrings, origNfa, acc, absIdx, startIdx, finishIdx) =
case prevStrings of
prevHd :: prevTl =>
let
val prevIdx = absIdx - String.size prevHd
val tl = hd :: tl
in
if startIdx < prevIdx then
(* keep backtracking *)
backtrackRange
( prevHd
, tl
, prevTl
, origNfa
, acc
, prevIdx
, startIdx
, finishIdx
)
else
let
val strIdx = startIdx - prevIdx + 1
val absIdx = absIdx + strIdx
in
loop
( strIdx
, prevHd
, tl
, prevTl
, origNfa
, origNfa
, acc
, absIdx
, absIdx
, finishIdx
)
end
end
| [] => raise Fail "nfa.sml 188: should not backtrack to empty list"
and loop
( strIdx
, hd
, tl
, prevStrings
, nfa
, origNfa
, acc
, absIdx
, startIdx
, finishIdx
) =
if strIdx = String.size hd then
case tl of
newHd :: newTl =>
loop
( 0
, newHd
, newTl
, hd :: prevStrings
, nfa
, origNfa
, acc
, absIdx
, startIdx
, finishIdx
)
| [] => acc
else if absIdx > finishIdx then
fun loop (pos, buffer, nfa, origNfa, startPos, acc, lastIdx) =
if pos = #textLength buffer then
acc
else if pos > lastIdx then
acc
else
let
val chr = String.sub (hd, strIdx)
val (nfa, state) = rebuild (nfa, chr, absIdx)
val chr = LineGap.substring (pos, 1, buffer)
val chr = String.sub (chr, 0)
val (nfa, state) = rebuild (nfa, chr, pos)
in
case state of
UNTESTED =>
loop
( strIdx + 1
, hd
, tl
, prevStrings
, nfa
, origNfa
, acc
, absIdx + 1
, startIdx
, finishIdx
)
| VALID foundIdx =>
VALID finishIdx =>
let
val acc = PersistentVector.append (startIdx, foundIdx, acc)
val acc = PersistentVector.append (startPos, finishIdx, acc)
in
loop
( strIdx + 1
, hd
, tl
, prevStrings
( finishIdx + 1
, buffer
, origNfa
, origNfa
, finishIdx + 1
, acc
, foundIdx + 1
, foundIdx + 1
, finishIdx
, lastIdx
)
end
| INVALID =>
let
val prevIdx = absIdx - strIdx
in
if startIdx < prevIdx then
backtrackRange
( hd
, tl
, prevStrings
, origNfa
, acc
, prevIdx
, startIdx
, finishIdx
)
else
let
val strIdx = startIdx - prevIdx + 1
val absIdx = prevIdx + strIdx
in
loop
( strIdx
, hd
, tl
, prevStrings
, origNfa
, origNfa
, acc
, absIdx
, startIdx + 1
, finishIdx
)
end
let val pos = startPos + 1
in loop (pos, buffer, origNfa, origNfa, pos, acc, lastIdx)
end
| UNTESTED =>
loop (pos + 1, buffer, nfa, origNfa, startPos, acc, lastIdx)
end
in
(* Prerequisite: move buffer to 'start' parameter before calling *)
fun getMatchesInRange (startIdx, finishIdx, buffer: LineGap.t, nfa) =
let
val {rightStrings, idx = bufferIdx, ...} = buffer
val strIdx = startIdx - bufferIdx
in
case rightStrings of
hd :: tl =>
if strIdx < String.size hd then
(* strIdx is in this string *)
loop
( strIdx
, hd
, tl
, []
, nfa
, nfa
, PersistentVector.empty
, startIdx
, startIdx
, finishIdx
)
else
(* strIdx is in tl *)
(case tl of
stlhd :: stltl =>
let
val strIdx = strIdx - String.size hd
in
loop
( strIdx
, stlhd
, stltl
, []
, nfa
, nfa
, PersistentVector.empty
, startIdx
, startIdx
, finishIdx
)
end
| [] => PersistentVector.empty)
| [] => PersistentVector.empty
end
loop (startIdx, buffer, nfa, nfa, 0, PersistentVector.empty, finishIdx)
end
end