reimplement function to search through text from scratch

fcore/app-type.sml

@@ -33,7 +33,7 @@ struct
     { mode = NORMAL_MODE ""
     , buffer = buffer
     , bufferModifyTime = time
-    , searchList = SearchList.empty
+    , searchList = PersistentVector.empty
     , windowWidth = windowWidth
     , windowHeight = windowHeight
     , startLine = 0

fcore/search-list/search-list.sml

@@ -1,99 +1,47 @@
 structure SearchList =
 struct
-  val empty = PersistentVector.empty
-
-  fun backtrackFull (pos, hd, absIdx, tl, acc, searchPos, searchString, prevTl) =
-    if pos < 0 then
-      case prevTl of
-        prevHd :: prevTl =>
-          let
-            val tl = hd :: tl
-          in
-            backtrackFull
-              ( String.size prevHd - 1
-              , prevHd
-              , absIdx
-              , tl
-              , acc
-              , searchPos
-              , searchString
-              , prevTl
-              )
-          end
-      | [] =>
-          (* Should never be called *)
-          raise Fail "SearchList.backtrackFull error: line 24\n"
-    else if searchPos <= 1 then
-      (* we are trying to backtrack to index 1, 
-       * and then continue are search from here *)
-      loopSearch (pos, hd, absIdx, tl, acc, 0, searchString, prevTl)
-    else
-      backtrackFull
-        (pos - 1, hd, absIdx - 1, tl, acc, searchPos - 1, searchString, prevTl)
-
-  and loopSearch (pos, hd, absIdx, tl, acc, searchPos, searchString, prevTl) =
-    if pos = String.size hd then
-      case tl of
-        newHd :: newTl =>
-          loopSearch
-            ( 0
-            , newHd
-            , absIdx
-            , newTl
-            , acc
-            , searchPos
-            , searchString
-            , hd :: prevTl
-            )
-      | [] => acc
-    else
-      let
-        val bufferChr = String.sub (hd, pos)
-        val searchChr = String.sub (searchString, searchPos)
-      in
-        if bufferChr = searchChr then
-          if searchPos + 1 = String.size searchString then
-            (* we fully matched the search string *)
-            let
-              val foundIdx = absIdx - String.size searchString + 1
-              val acc = PersistentVector.append (foundIdx, absIdx, acc)
-            in
-              loopSearch
-                (pos + 1, hd, absIdx + 1, tl, acc, 0, searchString, prevTl)
-            end
-          else
-            loopSearch
-              ( pos + 1
-              , hd
-              , absIdx + 1
-              , tl
-              , acc
-              , searchPos + 1
-              , searchString
-              , prevTl
-              )
-        else
-          (if searchPos = 0 then
-             loopSearch
-               (pos + 1, hd, absIdx + 1, tl, acc, 0, searchString, prevTl)
-           else
-             backtrackFull
-               (pos, hd, absIdx, tl, acc, searchPos, searchString, prevTl))
-      end
-
-  fun search ({rightStrings, leftStrings, ...}: LineGap.t, searchString) =
-    case rightStrings of
-      hd :: tl =>
-        loopSearch (0, hd, 0, tl, PersistentVector.empty, 0, searchString, [])
-    | [] => PersistentVector.empty
-
-  (* Prerequisite: move buffer/LineGap to start *)
-  fun build (buffer, searchString) =
-    if String.size searchString > 0 then search (buffer, searchString)
-    else PersistentVector.empty
-
   structure DfaGen = CaseInsensitiveDfa
 
+  fun buildLoop (idx, iterator, dfa, acc, curState, startPos, prevFinalPos) =
+    let
+      val iterator = LineGap.moveIteratorToIdx (idx, iterator)
+    in
+      if LineGap.isIteratorAtEnd iterator then
+        if prevFinalPos < 0 then acc
+        else PersistentVector.append (startPos, prevFinalPos, acc)
+      else
+        let
+          val chr = LineGap.subIterator (idx, iterator)
+          val newState = DfaGen.nextState (dfa, curState, chr)
+          val prevFinalPos =
+            if DfaGen.isFinal (dfa, newState) then idx else prevFinalPos
+        in
+          if DfaGen.isDead newState then
+            if prevFinalPos = ~1 then
+              (* no match found: restart search from `startPos + 1` *)
+              buildLoop (startPos + 1, iterator, dfa, acc, 0, startPos + 1, ~1)
+            else
+              (* match found: append and continue *)
+              let
+                val acc = PersistentVector.append (startPos, prevFinalPos, acc)
+
+                (* we start 1 idx after the final position we found *)
+                val newStart = prevFinalPos + 1
+              in
+                buildLoop (newStart, iterator, dfa, acc, 0, newStart, ~1)
+              end
+          else
+            buildLoop
+              (idx + 1, iterator, dfa, acc, newState, startPos, prevFinalPos)
+        end
+    end
+
+  fun build (iterator, dfa) =
+    if Vector.length dfa > 0 then
+      buildLoop (0, iterator, dfa, PersistentVector.empty, 0, 0, ~1)
+    else
+      PersistentVector.empty
+
   fun rangeLoop
     ( dfa
     , bufferPos