reimplement vi's 'j' motion, and remove the original function for this motion which was in cursor.sml

fcore/cursor.sml

@@ -132,147 +132,6 @@ struct
         if lineIdx = 0 then cursorIdx else cursorIdx - lineIdx - 1
       end
 
-  fun helpViJ
-    ( strPos
-    , str
-    , absIdx
-    , lineColumn
-    , preferredColumn
-    , hasPassedLine
-    , strTl
-    , lineTl
-    , prevIsLn
-    ) =
-    if strPos = String.size str then
-      case (strTl, lineTl) of
-        (shd :: stl, lhd :: ltl) =>
-          (* todo: possibly check if we have passed line,
-           * and if so, if there are any line breaks in the lineHd
-           * which we could use to skip searching part of the string. 
-           * However, this will likely have worse cache locality 
-           * as we switch to searching in string to searcing in line vector
-           * so perhaps not. *)
-          helpViJ
-            ( 0
-            , shd
-            , absIdx
-            , lineColumn
-            , preferredColumn
-            , hasPassedLine
-            , stl
-            , ltl
-            , prevIsLn
-            )
-      | (_, _) => (* empty, so return end of previous string *) absIdx - 1
-    else
-      case String.sub (str, strPos) of
-        #"\n" =>
-          if hasPassedLine then
-            (* reached end of line twice, 
-             * but line has fewer chars than preferredColumn *)
-            if prevIsLn then
-              (* line break is preceded by linebreak *)
-              absIdx
-            else
-              (* line break is preceded by graphical chr
-               * so go to graphical chr *)
-              absIdx - 1
-          else
-            (* reached end of line once;
-             * continue iterationg *)
-            helpViJ
-              ( strPos + 1
-              , str
-              , absIdx + 1
-              , 0
-              , preferredColumn
-              , true
-              , strTl
-              , lineTl
-              , true
-              )
-      | _ =>
-          if lineColumn = preferredColumn andalso hasPassedLine then
-            (* we're at the preferredColumn so return absIdx *)
-            absIdx
-          else
-            (* we're not in the preferred column, so keep iterating *)
-            helpViJ
-              ( strPos + 1
-              , str
-              , absIdx + 1
-              , lineColumn + 1
-              , preferredColumn
-              , hasPassedLine
-              , strTl
-              , lineTl
-              , false
-              )
-
-  fun viJ (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
-              (* strIdx is in this string *)
-              let
-                val lineColumn = getCursorColumn
-                  (strIdx, strHd, lnHd, leftStrings, leftLines, cursorIdx)
-              in
-                helpViJ
-                  ( strIdx
-                  , strHd
-                  , cursorIdx
-                  , lineColumn
-                  , lineColumn
-                  , false
-                  , strTl
-                  , lnTl
-                  , false
-                  )
-              end
-            else
-              (* strIdx must be in the strTl *)
-              (case (strTl, lnTl) of
-                 (nestStrHd :: nestStrTl, nestLnHd :: nestLnTl) =>
-                   let
-                     val strIdx = strIdx - String.size strHd
-                     val leftStrings = strHd :: leftStrings
-                     val leftLines = lnHd :: leftLines
-                     val lineColumn = getCursorColumn
-                       ( strIdx
-                       , nestStrHd
-                       , nestLnHd
-                       , leftStrings
-                       , leftLines
-                       , cursorIdx
-                       )
-                   in
-                     helpViJ
-                       ( strIdx
-                       , nestStrHd
-                       , cursorIdx
-                       , lineColumn
-                       , lineColumn
-                       , false
-                       , nestStrTl
-                       , nestLnTl
-                       , false
-                       )
-                   end
-               | (_, _) => cursorIdx)
-          end
-      | (_, _) => (* nowhere to go rightward, so return cursorIdx *) cursorIdx
-    end
-
   (* equivalent of vi's 'w' command *)
   val nextWord = ViWordDfa.startOfNextWord
 

fcore/move.sml

@@ -42,8 +42,6 @@ struct
     end
 end
 
-structure MoveViJ = MakeMove (struct val fMove = Cursor.viJ end)
-
 structure MoveToStartOfLine = MakeMove (struct val fMove = Cursor.vi0 end)
 
 signature DFA_MOVE =

fcore/normal-mode/normal-mode.sml

@@ -147,7 +147,7 @@ struct
   fun parseChr (app: app_type, count, chr, str, time) =
     case chr of
       #"h" => MoveViH.move (app, count)
-    | #"j" => MoveViJ.move (app, count)
+    | #"j" => NormalMove.moveCursorDown (app, count)
     | #"k" => NormalMove.moveCursorUp (app, count)
     | #"l" => MoveViL.move (app, count)
     | #"w" => MoveToNextWord.move (app, count)

fcore/normal-mode/normal-move.sml

@@ -132,6 +132,7 @@ struct
         else
           LineGap.idxToLineNumber (cursorIdx, buffer)
       val newCursorLineNumber = Int.max (cursorLineNumber - count, 0)
+      val column = if newCursorLineNumber = 0 then column - 1 else column
 
       val buffer = LineGap.goToLine (newCursorLineNumber, buffer)
       val lineIdx = LineGap.lineNumberToIdx (newCursorLineNumber, buffer)
@@ -143,7 +144,6 @@ struct
       val buffer = LineGap.goToIdx (lineIdx, buffer)
       val endOfLineIdx = Cursor.viDlr (buffer, lineIdx, 1)
 
-      val column = if newCursorLineNumber = 0 then column - 1 else column
       val cursorIdx = Int.min (endOfLineIdx, lineIdx + column)
 
       val buffer = LineGap.goToIdx (cursorIdx, buffer)
@@ -188,6 +188,94 @@ struct
         )
     end
 
+  fun moveCursorDown (app: app_type, count) =
+    let
+      val
+        { windowWidth
+        , windowHeight
+        , cursorIdx
+        , buffer
+        , startLine = prevLineNumber
+        , searchList
+        , searchString
+        , bufferModifyTime
+        , visualScrollColumn = prevScrollColumn
+        , ...
+        } = app
+
+      (* calculate new idx to move to *)
+      val buffer = LineGap.goToIdx (cursorIdx, buffer)
+      val startOfLine = Cursor.vi0 (buffer, cursorIdx)
+      val column = cursorIdx - startOfLine
+
+      val cursorLineNumber =
+        if Cursor.isNextChrEndOfLine (buffer, cursorIdx) then
+          LineGap.idxToLineNumber (cursorIdx + 1, buffer)
+        else
+          LineGap.idxToLineNumber (cursorIdx, buffer)
+
+      val newCursorLineNumber = cursorLineNumber + count
+      val newCursorLineNumber =
+        if cursorLineNumber >= #lineLength buffer - 2 then
+          Int.max (0, #lineLength buffer - 2)
+        else
+          newCursorLineNumber
+
+      val buffer = LineGap.goToLine (newCursorLineNumber, buffer)
+      val lineIdx = LineGap.lineNumberToIdx (newCursorLineNumber, buffer)
+      val buffer = LineGap.goToIdx (lineIdx, buffer)
+      val lineIdx =
+        if Cursor.isNextChrEndOfLine (buffer, lineIdx) then lineIdx
+        else lineIdx + 1
+
+      val buffer = LineGap.goToIdx (lineIdx, buffer)
+      val endOfLineIdx = Cursor.viDlr (buffer, lineIdx, 1)
+
+      val cursorIdx = Int.min (endOfLineIdx, lineIdx + column)
+
+      val buffer = LineGap.goToIdx (cursorIdx, buffer)
+
+      (* create draw message *)
+      val visualScrollColumn =
+        TextScroll.getScrollColumn
+          (buffer, cursorIdx, windowWidth, prevScrollColumn)
+
+      val startLine =
+        TextScroll.getStartLine
+          (prevLineNumber, newCursorLineNumber, windowHeight)
+
+      val buffer = LineGap.goToLine (startLine, buffer)
+
+      val drawMsg = NormalModeTextBuilder.build
+        ( startLine
+        , cursorIdx
+        , buffer
+        , windowWidth
+        , windowHeight
+        , searchList
+        , searchString
+        , visualScrollColumn
+        )
+      val drawMsg = Vector.concat drawMsg
+      val drawMsg = DrawMsg.DRAW_TEXT drawMsg
+      val drawMsg = [MailboxType.DRAW drawMsg]
+
+      val mode = NORMAL_MODE ""
+    in
+      NormalModeWith.bufferAndCursorIdx
+        ( app
+        , buffer
+        , cursorIdx
+        , mode
+        , startLine
+        , searchList
+        , drawMsg
+        , bufferModifyTime
+        , visualScrollColumn
+        )
+    end
+
+
   fun moveToLine (app: app_type, reqLine) =
     let
       val reqLine = reqLine - 1