1 files changed, 126 insertions, 0 deletions
diff --git a/indent/lua.vim b/indent/lua.vim
new file mode 100644
index 00000000..901ac854
--- /dev/null
+++ b/indent/lua.vim
@@ -0,0 +1,126 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'lua') == -1
+  
+" Vim indent file
+" Language: Lua
+" URL: https://github.com/tbastos/vim-lua
+
+" Initialization ------------------------------------------{{{1
+
+if exists("b:did_indent")
+  finish
+endif
+let b:did_indent = 1
+
+setlocal autoindent
+setlocal nosmartindent
+
+setlocal indentexpr=GetLuaIndent()
+setlocal indentkeys+=0=end,0=until,0=elseif,0=else
+
+" Only define the function once.
+if exists("*GetLuaIndent")
+  finish
+endif
+
+" Variables -----------------------------------------------{{{1
+
+let s:open_patt = '\%(\<\%(function\|if\|repeat\|do\)\>\|(\|{\)'
+let s:middle_patt = '\<\%(else\|elseif\)\>'
+let s:close_patt = '\%(\<\%(end\|until\)\>\|)\|}\)'
+
+let s:anon_func_start = '\S\+\s*[({].*\<function\s*(.*)\s*$'
+let s:anon_func_end = '\<end\%(\s*[)}]\)\+'
+
+" Expression used to check whether we should skip a match with searchpair().
+let s:skip_expr = "synIDattr(synID(line('.'),col('.'),1),'name') =~ 'luaComment\\|luaString'"
+
+" Auxiliary Functions -------------------------------------{{{1
+
+function s:IsInCommentOrString(lnum, col)
+  return synIDattr(synID(a:lnum, a:col, 1), 'name') =~ 'luaCommentLong\|luaStringLong'
+        \ && !(getline(a:lnum) =~ '^\s*\%(--\)\?\[=*\[') " opening tag is not considered 'in'
+endfunction
+
+" Find line above 'lnum' that isn't blank, in a comment or string.
+function s:PrevLineOfCode(lnum)
+  let lnum = prevnonblank(a:lnum)
+  while s:IsInCommentOrString(lnum, 1)
+    let lnum = prevnonblank(lnum - 1)
+  endwhile
+  return lnum
+endfunction
+
+" Gets line contents, excluding trailing comments.
+function s:GetContents(lnum)
+  return substitute(getline(a:lnum), '\v\m--.*$', '', '')
+endfunction
+
+" GetLuaIndent Function -----------------------------------{{{1
+
+function GetLuaIndent()
+  " if the line is in a long comment or string, don't change the indent
+  if s:IsInCommentOrString(v:lnum, 1)
+    return -1
+  endif
+
+  let prev_line = s:PrevLineOfCode(v:lnum - 1)
+  if prev_line == 0
+    " this is the first non-empty line
+    return 0
+  endif
+
+  let contents_cur = s:GetContents(v:lnum)
+  let contents_prev = s:GetContents(prev_line)
+
+  let original_cursor_pos = getpos(".")
+
+  let i = 0
+
+  " check if the previous line opens blocks
+  call cursor(v:lnum, 1)
+  let num_pairs = searchpair(s:open_patt, s:middle_patt, s:close_patt,
+        \ 'mrb', s:skip_expr, prev_line)
+  if num_pairs > 0
+    let i += num_pairs
+  endif
+
+  " special case: call(with, {anon = function() -- should indent only once
+  if num_pairs > 1 && contents_prev =~ s:anon_func_start
+    let i = 1
+  endif
+
+  " check if current line closes blocks
+  call cursor(prev_line, col([prev_line,'$']))
+  let num_pairs = searchpair(s:open_patt, s:middle_patt, s:close_patt,
+        \ 'mr', s:skip_expr, v:lnum)
+  if num_pairs > 0
+    let i -= num_pairs
+  endif
+
+  " special case: end}) -- end of call with anon func should unindent once
+  if num_pairs > 1 && contents_cur =~ s:anon_func_end
+    let i = -1
+  endif
+
+  " if the previous line closed a paren, unindent (except with anon funcs)
+  call cursor(prev_line - 1, col([prev_line - 1, '$']))
+  let num_pairs = searchpair('(', '', ')', 'mr', s:skip_expr, prev_line)
+  if num_pairs > 0 && contents_prev !~ s:anon_func_end
+    let i -= 1
+  endif
+
+  " if this line closed a paren, indent (except with anon funcs)
+  call cursor(prev_line, col([prev_line, '$']))
+  let num_pairs = searchpair('(', '', ')', 'mr', s:skip_expr, v:lnum)
+  if num_pairs > 0 && contents_cur !~ s:anon_func_end
+    let i += 1
+  endif
+
+  " restore cursor
+  call setpos(".", original_cursor_pos)
+
+  return indent(prev_line) + (&sw * i)
+
+endfunction
+
+endif