From 8ec6f1e40f0847f2d3b336dcf16b8ff132d5d57b Mon Sep 17 00:00:00 2001
From: Christian <cb@256bit.org>
Date: Wed, 18 Nov 2020 14:54:39 +0100
Subject: [PATCH] tabline formatter: prepare for vim9 script implementation

---
 .../extensions/tabline/formatters/default.vim | 78 ++++++++++---------
 1 file changed, 41 insertions(+), 37 deletions(-)

diff --git a/autoload/airline/extensions/tabline/formatters/default.vim b/autoload/airline/extensions/tabline/formatters/default.vim
index 5e68c94c..92b60350 100644
--- a/autoload/airline/extensions/tabline/formatters/default.vim
+++ b/autoload/airline/extensions/tabline/formatters/default.vim
@@ -1,45 +1,49 @@
 " MIT License. Copyright (c) 2013-2020 Bailey Ling et al.
-" vim: et ts=2 sts=2 sw=2
+" vim: et ts=2 sts=2 sw=2 et fdm=marker
 
 scriptencoding utf-8
 
-function! airline#extensions#tabline#formatters#default#format(bufnr, buffers)
-  let fnametruncate = get(g:, 'airline#extensions#tabline#fnametruncate', 0)
-  let fmod = get(g:, 'airline#extensions#tabline#fnamemod', ':~:.')
-  let _ = ''
+unlet! g:airline_experimental
+if !exists(":def") || (exists(":def") && get(g:, "airline_experimental", 0)==0)
+  function! airline#extensions#tabline#formatters#default#format(bufnr, buffers)
+    let fnametruncate = get(g:, 'airline#extensions#tabline#fnametruncate', 0)
+    let fmod = get(g:, 'airline#extensions#tabline#fnamemod', ':~:.')
+    let _ = ''
 
-  let name = bufname(a:bufnr)
-  if empty(name)
-    let _ .= '[No Name]'
-  elseif name =~ 'term://'
-    " Neovim Terminal
-    let _ = substitute(name, '\(term:\)//.*:\(.*\)', '\1 \2', '')
-  else
-    if get(g:, 'airline#extensions#tabline#fnamecollapse', 1)
-      " Does not handle non-ascii characters like Cyrillic: 'D/Учёба/t.c'
-      "let _ .= substitute(fnamemodify(name, fmod), '\v\w\zs.{-}\ze(\\|/)', '', 'g')
-      let _ .= pathshorten(fnamemodify(name, fmod))
+    let name = bufname(a:bufnr)
+    if empty(name)
+      let _ .= '[No Name]'
+    elseif name =~ 'term://'
+      " Neovim Terminal
+      let _ = substitute(name, '\(term:\)//.*:\(.*\)', '\1 \2', '')
     else
-      let _ .= fnamemodify(name, fmod)
+      if get(g:, 'airline#extensions#tabline#fnamecollapse', 1)
+        " Does not handle non-ascii characters like Cyrillic: 'D/Учёба/t.c'
+        "let _ .= substitute(fnamemodify(name, fmod), '\v\w\zs.{-}\ze(\\|/)', '', 'g')
+        let _ .= pathshorten(fnamemodify(name, fmod))
+      else
+        let _ .= fnamemodify(name, fmod)
+      endif
+      if a:bufnr != bufnr('%') && fnametruncate && strlen(_) > fnametruncate
+        let _ = airline#util#strcharpart(_, 0, fnametruncate)
+      endif
     endif
-    if a:bufnr != bufnr('%') && fnametruncate && strlen(_) > fnametruncate
-      let _ = airline#util#strcharpart(_, 0, fnametruncate)
+
+    return airline#extensions#tabline#formatters#default#wrap_name(a:bufnr, _)
+  endfunction
+
+  function! airline#extensions#tabline#formatters#default#wrap_name(bufnr, buffer_name)
+    let buf_nr_format = get(g:, 'airline#extensions#tabline#buffer_nr_format', '%s: ')
+    let buf_nr_show = get(g:, 'airline#extensions#tabline#buffer_nr_show', 0)
+    let buf_modified_symbol = g:airline_symbols.modified
+
+    let _ = buf_nr_show ? printf(buf_nr_format, a:bufnr) : ''
+    let _ .= substitute(a:buffer_name, '\\', '/', 'g')
+
+    if getbufvar(a:bufnr, '&modified') == 1
+      let _ .= buf_modified_symbol
     endif
-  endif
-
-  return airline#extensions#tabline#formatters#default#wrap_name(a:bufnr, _)
-endfunction
-
-function! airline#extensions#tabline#formatters#default#wrap_name(bufnr, buffer_name)
-  let buf_nr_format = get(g:, 'airline#extensions#tabline#buffer_nr_format', '%s: ')
-  let buf_nr_show = get(g:, 'airline#extensions#tabline#buffer_nr_show', 0)
-  let buf_modified_symbol = g:airline_symbols.modified
-
-  let _ = buf_nr_show ? printf(buf_nr_format, a:bufnr) : ''
-  let _ .= substitute(a:buffer_name, '\\', '/', 'g')
-
-  if getbufvar(a:bufnr, '&modified') == 1
-    let _ .= buf_modified_symbol
-  endif
-  return _
-endfunction
+    return _
+  endfunction
+else
+endif