From 265e6e1a90638820fd2b5c553ed85d162a0f9571 Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Tue, 30 Sep 2025 05:23:31 +0100
Subject: [PATCH] fix bugs in 'LineGap.subRight' (we were not passing nextIdx
 in recursion properly)

---
 src/line_gap.sml | 58 ++++++++++++++++++++----------------------------
 1 file changed, 24 insertions(+), 34 deletions(-)

diff --git a/src/line_gap.sml b/src/line_gap.sml
index bd7dc6e..ca40fd4 100644
--- a/src/line_gap.sml
+++ b/src/line_gap.sml
@@ -2263,42 +2263,32 @@ struct
   end
 
   fun subRight (findIdx, curIdx, hd, tl) =
-    if findIdx > curIdx + String.size hd - 1 then
-      case tl of
-        hd :: tl =>
-          if findIdx > curIdx + String.size hd - 1 then
-            subRight (findIdx, curIdx + String.size hd, hd, tl)
-          else
-            let val strIdx = findIdx - curIdx
-            in String.sub (hd, strIdx)
-            end
-      | [] => raise Fail "not found"
-    else
-      let val strIdx = findIdx - curIdx
-      in String.sub (hd, strIdx)
-      end
+    let
+      val nextIdx = curIdx + String.size hd
+    in
+      if findIdx > nextIdx - 1 then
+        case tl of
+          hd :: tl => subRight (findIdx, nextIdx, hd, tl)
+        | [] => raise Fail "not found"
+      else
+        let val strIdx = findIdx - curIdx
+        in String.sub (hd, strIdx)
+        end
+    end
 
   fun subLeft (findIdx, curIdx, hd, tl) =
-    if findIdx < curIdx - String.size hd then
-      case tl of
-        hd :: tl =>
-          if findIdx < curIdx - String.size hd then
-            subLeft (findIdx, curIdx - String.size hd, hd, tl)
-          else
-            let
-              val prevIdx = curIdx - String.size hd
-              val strIdx = findIdx - prevIdx
-            in
-              String.sub (hd, strIdx)
-            end
-      | [] => raise Fail "not found"
-    else
-      let
-        val prevIdx = curIdx - String.size hd
-        val strIdx = findIdx - prevIdx
-      in
-        String.sub (hd, strIdx)
-      end
+    let
+      val prevIdx = curIdx - String.size hd
+    in
+      if findIdx < prevIdx then
+        case tl of
+          hd :: tl => subLeft (findIdx, prevIdx, hd, tl)
+        | [] => raise Fail "not found"
+      else
+        let val strIdx = findIdx - prevIdx
+        in String.sub (hd, strIdx)
+        end
+    end
 
   fun sub (findIdx, buffer: t) =
     if findIdx >= #idx buffer then