From bab138ac3ccfdb02cec92d8e717d9df671214baf Mon Sep 17 00:00:00 2001
From: "Andy K. Massimino" <massimino@gatech.edu>
Date: Fri, 20 Jul 2018 06:43:57 -0400
Subject: [PATCH] Allow switching regexp engine for filetypes

---
 after/ftplugin/tex_matchup.vim | 3 +++
 autoload/matchup/loader.vim    | 7 ++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/after/ftplugin/tex_matchup.vim b/after/ftplugin/tex_matchup.vim
index 43e194e..a10fc0d 100644
--- a/after/ftplugin/tex_matchup.vim
+++ b/after/ftplugin/tex_matchup.vim
@@ -74,6 +74,9 @@ function! s:setup_match_words()
 
     " the syntax method is too slow for latex
     let b:match_skip = 'r:\\\@<!\%(\\\\\)*%'
+
+    " the old regexp engine is a bit faster '\%#=1'
+    let b:matchup_regexpengine = 1
 endfunction
 
 if get(g:, 'vimtex_enabled',
diff --git a/autoload/matchup/loader.vim b/autoload/matchup/loader.vim
index f3f8cfe..af1f3cf 100644
--- a/autoload/matchup/loader.vim
+++ b/autoload/matchup/loader.vim
@@ -456,6 +456,11 @@ function! s:init_delim_regexes() abort " {{{1
   " use a flag for b:match_ignorecase
   let l:ic = get(b:, 'match_ignorecase', 0) ? '\c' : '\C'
 
+  " if a particular engine is specified, use that for the patterns
+  " (currently only applied to delim_re TODO)
+  let l:eng = string(get(b:, 'matchup_regexpengine', 0))
+  let l:eng = l:eng > 0 ? '\%#='.l:eng : ''
+
   for l:k in keys(s:sidedict)
     let l:re.delim_tex._engine_info.has_zs[l:k]
           \ = l:re.delim_tex[l:k] =~# g:matchup#re#zs
@@ -465,7 +470,7 @@ function! s:init_delim_regexes() abort " {{{1
     else
       " since these patterns are used in searchpos(),
       " be explicit about regex mode (set magic mode and ignorecase)
-      let l:re.delim_tex[l:k] = '\m' . l:ic . l:re.delim_tex[l:k]
+      let l:re.delim_tex[l:k] = l:eng . '\m' . l:ic . l:re.delim_tex[l:k]
     endif
 
     let l:re.delim_all[l:k] = l:re.delim_tex[l:k]