From d63201ada75538b7253b7b8eb5bc0f2ff1dda2ed Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Sun, 21 Sep 2025 17:49:30 +0100
Subject: [PATCH] reimplement vi's 'l' motion so that we only skip a newline
 when it is preceded by a non-newline character

---
 fcore/cursor-dfa/vi-l-dfa.sml                 | 53 +++++++++++++++++++
 fcore/cursor.sml                              |  2 +-
 .../text-builder/text-builder-with-cursor.sml |  6 +--
 .../text-builder-with-highlight.sml           |  6 +--
 shf.mlb                                       |  1 +
 5 files changed, 59 insertions(+), 9 deletions(-)
 create mode 100644 fcore/cursor-dfa/vi-l-dfa.sml

diff --git a/fcore/cursor-dfa/vi-l-dfa.sml b/fcore/cursor-dfa/vi-l-dfa.sml
new file mode 100644
index 0000000..48cb613
--- /dev/null
+++ b/fcore/cursor-dfa/vi-l-dfa.sml
@@ -0,0 +1,53 @@
+structure ViLDfa =
+struct
+  val startState: Word8.word = 0w0
+  val newlineState: Word8.word = 0w1
+  val chrState: Word8.word = 0w2
+  val newlineAfterCHrState: Word8.word = 0w3
+
+  fun makeStart i =
+    if Char.chr i = #"\n" then newlineState else chrState
+
+  fun makeChr i =
+    if Char.chr i = #"\n" then newlineAfterCHrState else chrState
+
+  val startTable = Vector.tabulate (255, makeStart)
+  val newlineTable = startTable
+  val chrTable = Vector.tabulate (255, makeChr)
+  val newlineAfterCHrTable = startTable
+
+  val tables = #[startTable, newlineTable, chrTable, newlineAfterCHrTable]
+
+  fun next (currentState, chr) =
+    let val table = Vector.sub (tables, Word8.toInt currentState)
+    in Vector.sub (table, Char.ord chr)
+    end
+
+  structure ViL =
+    MakeNextDfaLoop
+      (struct
+         val startState = startState
+
+         fun loop (idx, absIdx, str, tl, currentState, counter) =
+           if idx = String.size str then
+             case tl of
+               str :: tl => loop (0, absIdx, str, tl, currentState, counter)
+             | [] => absIdx
+           else
+             let
+               val chr = String.sub (str, idx)
+               val newState = next (currentState, chr)
+             in
+               if newState = newlineAfterCHrState then
+                 loop (idx + 1, absIdx + 1, str, tl, newState, counter)
+               else if counter - 1 = ~1 then
+                 absIdx
+               else
+                 loop (idx + 1, absIdx + 1, str, tl, newState, counter - 1)
+             end
+
+         val fStart = loop
+       end)
+
+  val next = ViL.next
+end
diff --git a/fcore/cursor.sml b/fcore/cursor.sml
index dd2fafc..c25f00a 100644
--- a/fcore/cursor.sml
+++ b/fcore/cursor.sml
@@ -56,7 +56,7 @@ struct
   val viDlr = ViDlrDfa.next
   val viDlrForDelete = ViDlrDfa.nextForDelete
 
-  val viL = ViHlDfa.l
+  val viL = ViLDfa.next
   val viH = ViHlDfa.h
 
   fun helpGetCursorColumn (distanceFromLine, strList, lineList) =
diff --git a/fcore/text-builder/text-builder-with-cursor.sml b/fcore/text-builder/text-builder-with-cursor.sml
index bd980a4..48c5863 100644
--- a/fcore/text-builder/text-builder-with-cursor.sml
+++ b/fcore/text-builder/text-builder-with-cursor.sml
@@ -137,8 +137,6 @@ struct
             acc
           else
             let
-              val posX = #startX env
-              val posY = posY + TC.ySpace
               val acc =
                 if absIdx = cursorIdx then
                   Utils.makeCursor (posX, posY, env) :: acc
@@ -151,8 +149,8 @@ struct
                 , stl
                 , line
                 , ltl
-                , posX
-                , posY
+                , #startX env
+                , posY + TC.ySpace
                 , 0
                 , lineNumber + 1
                 , absIdx + 1
diff --git a/fcore/text-builder/text-builder-with-highlight.sml b/fcore/text-builder/text-builder-with-highlight.sml
index aba1a14..ce8daea 100644
--- a/fcore/text-builder/text-builder-with-highlight.sml
+++ b/fcore/text-builder/text-builder-with-highlight.sml
@@ -234,8 +234,6 @@ struct
                 acc
               else
                 let
-                  val posX = #startX env
-                  val posY = posY + TC.ySpace
                   val acc =
                     if absIdx = cursorIdx then
                       Utils.makeCursor (posX, posY, env) :: acc
@@ -248,8 +246,8 @@ struct
                     , stl
                     , line
                     , ltl
-                    , posX
-                    , posY
+                    , #startX env
+                    , posY + TC.ySpace
                     , 0
                     , lineNumber + 1
                     , absIdx + 1
diff --git a/shf.mlb b/shf.mlb
index 88f8575..e12d73f 100644
--- a/shf.mlb
+++ b/shf.mlb
@@ -34,6 +34,7 @@ in
   fcore/cursor-dfa/vi-word-dfa.sml
   fcore/cursor-dfa/vi-caps-word-dfa.sml
   fcore/cursor-dfa/vi-dlr-dfa.sml
+  fcore/cursor-dfa/vi-l-dfa.sml
   fcore/cursor-dfa/vi-hl-dfa.sml
   fcore/rect.sml
   fcore/pipe-cursor.sml