Show alternate buffer in statusline.

Toggle showing alternate buffer number and name for the current buffer,
if it exists, with <Leader>#.  Off by default.

diff --git a/.vimrc b/.vimrc
index a589ea0..68357f3 100644 (file)
--- a/.vimrc
+++ b/.vimrc
@@ -204,6 +204,7 @@ fun! Iain_Vars() "{{{2
   call Prep_Var("g:iainextracolumnsnumber", "''")
   call Prep_Var("g:iainextracolumnslist", "''")
   call Prep_Var("b:iaincul", 0)
+  call Prep_Var("b:iainalt", 0)
   if has("signs")
     call Prep_Var("g:marksigns", 0)
     call Prep_Var("g:firstsign", 100)
@@ -449,6 +450,8 @@ call Mapping(">", ":call Resize_Columns('+')<CR>:<CR>")
 call Mapping("<", ":call Resize_Columns('-')<CR>:<CR>")
 " Clear search pattern with \/.
 call Mapping("/", ":let @/=\"\"<CR>:<CR>")
+" Toggle alternate buffer name with \#.
+call Mapping("#", ":call Cycle_Alt()<CR>:<CR>")
 
 " Set graphical window title.
 if has("win32") || has("win64")
@@ -659,13 +662,24 @@ fun! Show_Paste() "{{{2
   endif
 endfun "}}}2
 
+" Helper for status line.
+" Show alternate buffer number and name.
+fun! Show_Alt() "{{{2
+  let l:alt = bufnr("#")
+  if l:alt < 0 || l:alt == bufnr("") || ! b:iainalt
+    return ""
+  endif
+
+  return " " . l:alt . ": " . expand("#:t")
+endfun "}}}2
+
 " Show the status line.
 fun! Show_StatusLine() "{{{2
   if ! has("statusline")
     return
   endif
   call Iain_Vars()
-  let l:sl1='%2n\:\ %<%1*%f%0*\ [%{Show_List()}%{Show_Case()}%{Show_Tabstop()}%{Show_Paste()}%Y%M%R]\ '
+  let l:sl1='%2n\:\ %<%1*%f%0*\ [%{Show_List()}%{Show_Case()}%{Show_Tabstop()}%{Show_Paste()}%Y%M%R]%{Show_Alt()}\ '
   let l:sl3='L:%1*%4.6l%0*/%-4.6L\ C:%1*%3.6c%0*\ \|\ %P'
   let l:hexformat='%b'
   if b:iainhex
@@ -949,6 +963,13 @@ fun! Cycle_Quickfix() "{{{2
   endif
 endfun "}}}2
 
+" Toggle showing alternate buffer information.
+fun! Cycle_Alt() "{{{2
+  call Iain_Vars()
+  let b:iainalt = ! b:iainalt
+  call Show_StatusLine()
+endfun "{{{2
+
 " Swap hex/decimal statusline with \x.
 call Mapping("x", ":call Cycle_HexStatusLine()<CR>:<CR>")
 " Change statusline verbosity with \v.