reimplement vi's '$' motion as a DFA, also eliminating a bug that involves double deleteion in the process

fcore/app-update.sml

@@ -509,7 +509,7 @@ struct
           * We also rely on helpRemoveChr to handle backwards-movement logic:
           * If cursorIdx is at \n after deletion, then stop.
           * Else, move back one chr. *)
-          val lastChr = Cursor.viDlr (buffer, cursorIdx)
+          val lastChr = Cursor.viDlr (buffer, cursorIdx, 1)
           val length = lastChr - cursorIdx
           val buffer = LineGap.delete (cursorIdx, length, buffer)
 
@@ -522,39 +522,23 @@ struct
         end
     end
 
-  fun helpDeleteLine (app: app_type, buffer, cursorIdx, otherIdx, count) =
-    if count = 0 then
-      let
-        val otherIdx = Cursor.clipIdx (buffer, otherIdx)
-        val length = otherIdx - cursorIdx
-        val buffer = LineGap.delete (cursorIdx, length, buffer)
-
-        val {searchList, searchString, ...} = app
-        val (buffer, searchList) = deleteSearchList
-          (cursorIdx, length, searchString, searchList, buffer)
-
-        val buffer = LineGap.goToIdx (cursorIdx, buffer)
-        val cursorIdx = Cursor.clipIdx (buffer, cursorIdx)
-      in
-        Finish.buildTextAndClear (app, buffer, cursorIdx, searchList)
-      end
-    else
-      let
-        (* get otherIdx, where cursor will want to go after motion. *)
-        val buffer = LineGap.goToIdx (otherIdx, buffer)
-        val newOtherIdx = Cursor.viDlr (buffer, otherIdx)
-        val newOtherIdx = Cursor.viL (buffer, newOtherIdx)
-        val newCount = if newOtherIdx = otherIdx then 0 else count - 1
-      in
-        helpDeleteLine (app, buffer, cursorIdx, newOtherIdx, newCount)
-      end
-
   fun deleteLine (app: app_type, count) =
     let
-      val {buffer, cursorIdx, ...} = app
+      val {buffer, cursorIdx, searchList, searchString, ...} = app
-      val cursorIdx = Cursor.vi0 (buffer, cursorIdx)
+      val buffer = LineGap.goToIdx (cursorIdx, buffer)
+
+      val startIdx = Cursor.vi0 (buffer, cursorIdx)
+      val finishIdx = Cursor.viDlrForDelete (buffer, cursorIdx, count)
+
+      val length = finishIdx - startIdx
+      val buffer = LineGap.delete (startIdx, length, buffer)
+
+      val (buffer, searchList) = deleteSearchList
+        (startIdx, length, searchString, searchList, buffer)
+
+      val buffer = LineGap.goToIdx (startIdx, buffer)
     in
-      helpDeleteLine (app, buffer, cursorIdx, cursorIdx, count)
+      Finish.buildTextAndClear (app, buffer, cursorIdx, searchList)
     end
 
   fun helpDeleteLineBack (app, buffer, low, high, count) =
@@ -587,7 +571,7 @@ struct
     let
       val {buffer, cursorIdx, ...} = app
       val low = Cursor.vi0 (buffer, cursorIdx)
-      val high = Cursor.viDlr (buffer, cursorIdx) + 1
+      val high = Cursor.viDlr (buffer, cursorIdx, 1) + 1
     in
       helpDeleteLineBack (app, buffer, low, high, count)
     end

fcore/cursor-dfa/vi-dlr-dfa.sml

@@ -0,0 +1,56 @@
+structure ViDlrDfa =
+struct
+  val startState: Word8.word = 0w0
+  val newlineState: Word8.word = 0w1
+  val notNewlineState = 0w2
+
+  fun makeStart i =
+    if Char.chr i = #"\n" then newlineState else notNewlineState
+
+  val startTable = Vector.tabulate (255, makeStart)
+  val newlineTable = startTable
+  val notNewlineTable = startTable
+
+  val tables = #[startTable, newlineTable, notNewlineTable]
+
+  fun isFinal currentState = currentState = newlineState
+
+  structure ViDlr =
+    MakeNextDfaLoop
+      (struct
+         val startState = startState
+
+         structure Folder =
+           MakeCharFolderNext
+             (struct
+                val startState = startState
+                val tables = tables
+
+                fun finish x = x - 1
+                val isFinal = isFinal
+              end)
+
+         val fStart = Folder.foldNext
+       end)
+
+  structure ViDlrForDelete =
+    MakeNextDfaLoop
+      (struct
+         val startState = startState
+
+         structure Folder =
+           MakeCharFolderNext
+             (struct
+                val startState = startState
+                val tables = tables
+
+                fun finish x = x + 1
+                val isFinal = isFinal
+              end)
+
+         val fStart = Folder.foldNext
+       end)
+
+  val next = ViDlr.next
+  val nextForDelete = ViDlrForDelete.next
+end

fcore/cursor.sml

@@ -47,67 +47,8 @@ struct
 
   fun vi0 (lineGap, cursorIdx) = Vi0.foldPrev (lineGap, cursorIdx, ())
 
-  fun helpViDlr (strPos, str, absIdx, strTl, lineTl) =
+  val viDlr = ViDlrDfa.next
-    if strPos = String.size str then
+  val viDlrForDelete = ViDlrDfa.nextForDelete
-      case (strTl, lineTl) of
-        (shd :: stl, lhd :: ltl) => helpViDlr (0, shd, absIdx, stl, ltl)
-      | (_, _) => absIdx - 1
-    else
-      case String.sub (str, strPos) of
-        #"\n" => absIdx - 1
-      | _ => helpViDlr (strPos + 1, str, absIdx + 1, strTl, lineTl)
-
-  fun viDlr (lineGap: LineGap.t, cursorIdx) =
-    let
-      val
-        {rightStrings, idx = bufferIdx, rightLines, leftStrings, leftLines, ...} =
-        lineGap
-    in
-      case (rightStrings, rightLines) of
-        (strHd :: strTl, lnHd :: lnTl) =>
-          let
-            (* convert absolute cursorIdx to idx relative to hd string *)
-            val strIdx = cursorIdx - bufferIdx
-          in
-            if strIdx < String.size strHd then
-              if String.sub (strHd, strIdx) <> #"\n" then
-                (* not in double linebreak *)
-                helpViDlr (strIdx + 1, strHd, cursorIdx + 1, strTl, lnTl)
-              else (* check if we are in double linebreak *) if strIdx - 1 >= 0 then
-                if String.sub (strHd, strIdx - 1) = #"\n" then
-                  (* we are in double linebreak, so do nothing *)
-                  cursorIdx
-                else
-                  (* not in double linebreak, so iterate *)
-                  helpViDlr (strIdx + 1, strHd, cursorIdx + 1, strTl, lnTl)
-              else
-                (* check if double linebreak in strTl *)
-                (case strTl of
-                   nestStrHd :: _ =>
-                     if String.sub (nestStrHd, 0) = #"\n" then
-                       cursorIdx
-                     else
-                       helpViDlr (strIdx + 1, strHd, cursorIdx + 1, strTl, lnTl)
-                 | [] => cursorIdx)
-            else
-              (* strIdx must be in the strTl *)
-              (case (strTl, lnTl) of
-                 (nestStrHd :: nestStrTl, nestLnHd :: nestLnTl) =>
-                   let
-                     val strIdx = strIdx - String.size strHd
-                   in
-                     helpViDlr
-                       ( strIdx + 1
-                       , nestStrHd
-                       , cursorIdx + 1
-                       , nestStrTl
-                       , nestLnTl
-                       )
-                   end
-               | (_, _) => cursorIdx)
-          end
-      | (_, _) => (* nowhere to go, so return cursorIdx *) cursorIdx
-    end
 
   fun helpViL (strIdx, hd, cursorIdx, tl) =
     if String.sub (hd, strIdx) = #"\n" then

fcore/move.sml

@@ -43,7 +43,6 @@ structure MoveViK = MakeMove (struct val fMove = Cursor.viK end)
 structure MoveViL = MakeMove (struct val fMove = Cursor.viL end)
 
 structure MoveToStartOfLine = MakeMove (struct val fMove = Cursor.vi0 end)
-structure MoveToEndOfLine = MakeMove (struct val fMove = Cursor.viDlr end)
 
 signature DFA_MOVE =
 sig
@@ -82,3 +81,5 @@ structure MoveToEndOfPrevWord =
   MakeDfaMove (struct val fMove = Cursor.endOfPrevWord end)
 structure MoveToEndOfPrevWORD =
   MakeDfaMove (struct val fMove = Cursor.endOfPrevWORD end)
+
+structure MoveToEndOfLine = MakeDfaMove (struct val fMove = Cursor.viDlr end)

shf-tests.mlb

@@ -25,6 +25,7 @@ in
   fcore/cursor-dfa/make-dfa-loop.sml
   fcore/cursor-dfa/vi-WORD-dfa.sml
   fcore/cursor-dfa/vi-word-dfa.sml
+  fcore/cursor-dfa/vi-dlr-dfa.sml
 end
 fcore/cursor.sml
 fcore/text-window.sml

shf.mlb

@@ -25,6 +25,7 @@ in
   fcore/cursor-dfa/make-dfa-loop.sml
   fcore/cursor-dfa/vi-WORD-dfa.sml
   fcore/cursor-dfa/vi-word-dfa.sml
+  fcore/cursor-dfa/vi-dlr-dfa.sml
 end
 fcore/cursor.sml
 fcore/text-window.sml