progress reimplementing 'j' motion to pass new tests

fcore/normal-mode/normal-move.sml

@@ -275,21 +275,45 @@ struct
 
           val buffer = LineGap.goToLine (newCursorLineNumber, buffer)
           val lineIdx = LineGap.lineNumberToIdx (newCursorLineNumber, buffer)
-
           val buffer = LineGap.goToIdx (lineIdx, buffer)
-
-          val lineIdx =
-            if Cursor.isPrevChrStartOfLine (buffer, lineIdx) then lineIdx
-            else lineIdx + 1
-
-          val lineIdx =
-            if lineIdx >= #textLength buffer - 1 then
-              Int.max (0, #textLength buffer - 1)
-            else
-              lineIdx
         in
-          finishMoveCursorUpDown
+          if lineIdx >= #textLength buffer then
-            (app, newCursorLineNumber, buffer, column, lineIdx)
+            (* we reached last line *)
+            let
+              val lineIdx = Int.max (#textLength buffer - 1, 0)
+              val buffer = LineGap.goToIdx (lineIdx, buffer)
+              val startOfLine = Cursor.vi0 (buffer, lineIdx)
+            in
+              if cursorIdx >= startOfLine then
+                (* we are already on last line so don't move *)
+                NormalFinish.buildTextAndClear
+                  (app, buffer, cursorIdx, searchList, [], bufferModifyTime)
+              else
+                finishMoveCursorUpDown
+                  (app, newCursorLineNumber, buffer, column, startOfLine)
+            end
+          else if lineIdx = #textLength buffer - 1 then
+            (* last line in buffer ends with \n
+             * and we just reached it *)
+            let val () = print "296\n"
+            in raise Fail ""
+            end
+          else
+            let
+              val lineIdx =
+                if lineIdx >= #textLength buffer - 2 then
+                  Int.max (0, #textLength buffer - 2)
+                else
+                  lineIdx
+
+              val buffer = LineGap.goToIdx (lineIdx, buffer)
+              val lineIdx =
+                if Cursor.isOnNewlineAfterChr (buffer, lineIdx) then lineIdx + 1
+                else lineIdx
+            in
+              finishMoveCursorUpDown
+                (app, newCursorLineNumber, buffer, column, lineIdx)
+            end
         end
     end
 

temp.txt

@@ -1,2 +1,2 @@
-hello world
+hello
-time to go
+world

test/normal-move.sml

@@ -382,7 +382,7 @@ struct
              val app = AppWith.idx (app, initialCursorIdx)
 
              (* act *)
-             val {cursorIdx, ...} = TestUtils.updateMany (app, "2j")
+             val {cursorIdx, ...} = TestUtils.update (app, CHAR_EVENT #"j")
 
              (* assert *)
              val expectedIdx = 10
@@ -409,11 +409,11 @@ struct
            in
              Expect.isTrue (cursorIdx = expectedIdx)
            end)
-    , test "goes to last char in file when last char is not a newline" (fn _ =>
+    , test "goes to last line in file when last char is not a newline" (fn _ =>
         let
           (* arrange *)
           val str = "hello\nworld"
-          val initialCursorIdx = 6
+          val initialCursorIdx = 0
 
           val app = TestUtils.init str
           val app = AppWith.idx (app, initialCursorIdx)
@@ -422,7 +422,7 @@ struct
           val {cursorIdx, ...} = TestUtils.update (app, CHAR_EVENT #"j")
 
           (* assert *)
-          val expectedIdx = String.size str - 1
+          val expectedIdx = 6
         in
           Expect.isTrue (cursorIdx = expectedIdx)
         end)
@@ -441,6 +441,27 @@ struct
              (* act *)
              val {cursorIdx, ...} = TestUtils.update (app, CHAR_EVENT #"j")
 
+             (* assert *)
+             val expectedIdx = initialCursorIdx
+           in
+             Expect.isTrue (cursorIdx = expectedIdx)
+           end)
+    , test
+        "does not go to last chr in file \
+        \when last chr is a newline preceded by a non-newline \
+        \and a count is provided"
+        (fn _ =>
+           let
+             (* arrange *)
+             val str = "hello\nworld\n"
+             val initialCursorIdx = 0
+
+             val app = TestUtils.init str
+             val app = AppWith.idx (app, initialCursorIdx)
+
+             (* act *)
+             val {cursorIdx, ...} = TestUtils.updateMany (app, "2j")
+
              (* assert *)
              val expectedIdx = initialCursorIdx
            in