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