Add syntax files from upstream vim repository

indent/lua.vim

@@ -1,3 +1,70 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim indent file
+" Language:	Lua script
+" Maintainer:	Marcus Aurelius Farias <marcus.cf 'at' bol.com.br>
+" First Author:	Max Ischenko <mfi 'at' ukr.net>
+" Last Change:	2017 Jun 13
+
+" Only load this indent file when no other was loaded.
+if exists("b:did_indent")
+  finish
+endif
+let b:did_indent = 1
+
+setlocal indentexpr=GetLuaIndent()
+
+" To make Vim call GetLuaIndent() when it finds '\s*end' or '\s*until'
+" on the current line ('else' is default and includes 'elseif').
+setlocal indentkeys+=0=end,0=until
+
+setlocal autoindent
+
+" Only define the function once.
+if exists("*GetLuaIndent")
+  finish
+endif
+
+function! GetLuaIndent()
+  " Find a non-blank line above the current line.
+  let prevlnum = prevnonblank(v:lnum - 1)
+
+  " Hit the start of the file, use zero indent.
+  if prevlnum == 0
+    return 0
+  endif
+
+  " Add a 'shiftwidth' after lines that start a block:
+  " 'function', 'if', 'for', 'while', 'repeat', 'else', 'elseif', '{'
+  let ind = indent(prevlnum)
+  let prevline = getline(prevlnum)
+  let midx = match(prevline, '^\s*\%(if\>\|for\>\|while\>\|repeat\>\|else\>\|elseif\>\|do\>\|then\>\)')
+  if midx == -1
+    let midx = match(prevline, '{\s*$')
+    if midx == -1
+      let midx = match(prevline, '\<function\>\s*\%(\k\|[.:]\)\{-}\s*(')
+    endif
+  endif
+
+  if midx != -1
+    " Add 'shiftwidth' if what we found previously is not in a comment and
+    " an "end" or "until" is not present on the same line.
+    if synIDattr(synID(prevlnum, midx + 1, 1), "name") != "luaComment" && prevline !~ '\<end\>\|\<until\>'
+      let ind = ind + shiftwidth()
+    endif
+  endif
+
+  " Subtract a 'shiftwidth' on end, else, elseif, until and '}'
+  " This is the part that requires 'indentkeys'.
+  let midx = match(getline(v:lnum), '^\s*\%(end\>\|else\>\|elseif\>\|until\>\|}\)')
+  if midx != -1 && synIDattr(synID(v:lnum, midx + 1, 1), "name") != "luaComment"
+    let ind = ind - shiftwidth()
+  endif
+
+  return ind
+endfunction
+
+endif
 if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'lua') == -1
   
 " Vim indent file