From 8694a10a01357e11e91838de70ca7d985be29493 Mon Sep 17 00:00:00 2001
From: Russell Wright Helder <rhelder.git@gmail.com>
Date: Wed, 27 Nov 2024 16:42:49 -0800
Subject: [PATCH 1/2] Check for numbers after markers when setting fold level

---
 autoload/vimtex/fold/markers.vim | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/autoload/vimtex/fold/markers.vim b/autoload/vimtex/fold/markers.vim
index ecef7347b41..afd831eb390 100644
--- a/autoload/vimtex/fold/markers.vim
+++ b/autoload/vimtex/fold/markers.vim
@@ -34,12 +34,22 @@ endfunction
 
 " }}}1
 function! s:folder.level(line, lnum) abort dict " {{{1
-  if a:line =~# self.re.start
+  let l:start = matchlist(a:line, self.re.start . '\(\d\{0,2}\)')
+  let l:end = matchlist(a:line, self.re.end . '\(\d\{0,2}\)')
+  if !empty(l:start)
+    if !empty(l:start[1])
+      return '>' . l:start[1]
+    else
+      return 'a1'
+    endif
     let self.opened = 1
-    return 'a1'
-  elseif a:line =~# self.re.end
+  elseif !empty(l:end)
+    if !empty(l:end[1])
+      return '<' . l:end[1]
+    else
+      return 's1'
+    endif
     let self.opened = 0
-    return 's1'
   endif
 endfunction
 

From 1412748bfc232519c4610388af7e26bf9a9cd321 Mon Sep 17 00:00:00 2001
From: Russell Wright Helder <rhelder.git@gmail.com>
Date: Sun, 8 Dec 2024 07:54:36 -0800
Subject: [PATCH 2/2] Incorporate recommended changes

*   Use ternary operator in return value
*   Only allow one digit after marker
*   Use '..' rather than '.' for concatenation
---
 autoload/vimtex/fold/markers.vim | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/autoload/vimtex/fold/markers.vim b/autoload/vimtex/fold/markers.vim
index afd831eb390..0ea255f392f 100644
--- a/autoload/vimtex/fold/markers.vim
+++ b/autoload/vimtex/fold/markers.vim
@@ -34,21 +34,17 @@ endfunction
 
 " }}}1
 function! s:folder.level(line, lnum) abort dict " {{{1
-  let l:start = matchlist(a:line, self.re.start . '\(\d\{0,2}\)')
-  let l:end = matchlist(a:line, self.re.end . '\(\d\{0,2}\)')
+  let l:start = matchlist(a:line, self.re.start .. '\(\d\?\)')
+  let l:end = matchlist(a:line, self.re.end .. '\(\d\?\)')
   if !empty(l:start)
-    if !empty(l:start[1])
-      return '>' . l:start[1]
-    else
-      return 'a1'
-    endif
+    return empty(l:start[1])
+          \ ? 'a1'
+          \ : '>' .. l:start[1]
     let self.opened = 1
   elseif !empty(l:end)
-    if !empty(l:end[1])
-      return '<' . l:end[1]
-    else
-      return 's1'
-    endif
+    return empty(l:end[1])
+          \ ? 's1'
+          \ : '<' .. l:end[1]
     let self.opened = 0
   endif
 endfunction