neovim/runtime/indent/zimbu.vim

" Vim indent file
" Language:	Zimbu
" Maintainer:	The Vim Project <https://github.com/vim/vim>
" Last Change:	2023 Aug 10
" Former Maintainer:	Bram Moolenaar <Bram@vim.org>

" Only load this indent file when no other was loaded.
if exists("b:did_indent")
   finish
endif
let b:did_indent = 1

setlocal ai nolisp nocin
setlocal indentexpr=GetZimbuIndent(v:lnum)
setlocal indentkeys=0{,0},!^F,o,O,0=ELSE,0=ELSEIF,0=CASE,0=DEFAULT,0=FINALLY

" We impose recommended defaults: no Tabs, 'shiftwidth' = 2
setlocal sw=2 et

let b:undo_indent = "setl ai< cin< et< indentkeys< indentexpr< lisp< sw<"

" Only define the function once.
if exists("*GetZimbuIndent")
  finish
endif

let s:cpo_save = &cpo
set cpo&vim

" Come here when loading the script the first time.

let s:maxoff = 50	" maximum number of lines to look backwards for ()

func GetZimbuIndent(lnum)
  let prevLnum = prevnonblank(a:lnum - 1)
  if prevLnum == 0
    " This is the first non-empty line, use zero indent.
    return 0
  endif

  " Taken from Python indenting:
  " If the previous line is inside parenthesis, use the indent of the starting
  " line.
  " Trick: use the non-existing "dummy" variable to break out of the loop when
  " going too far back.
  call cursor(prevLnum, 1)
  let parlnum = searchpair('(\|{\|\[', '', ')\|}\|\]', 'nbW',
	  \ "line('.') < " . (prevLnum - s:maxoff) . " ? dummy :"
	  \ . " synIDattr(synID(line('.'), col('.'), 1), 'name')"
	  \ . " =~ '\\(Comment\\|String\\|Char\\)$'")
  if parlnum > 0
    let plindent = indent(parlnum)
    let plnumstart = parlnum
  else
    let plindent = indent(prevLnum)
    let plnumstart = prevLnum
  endif


  " When inside parenthesis: If at the first line below the parenthesis add
  " two 'shiftwidth', otherwise same as previous line.
  " i = (a
  "       + b
  "       + c)
  call cursor(a:lnum, 1)
  let p = searchpair('(\|{\|\[', '', ')\|}\|\]', 'bW',
	  \ "line('.') < " . (a:lnum - s:maxoff) . " ? dummy :"
	  \ . " synIDattr(synID(line('.'), col('.'), 1), 'name')"
	  \ . " =~ '\\(Comment\\|String\\|Char\\)$'")
  if p > 0
    if p == prevLnum
      " When the start is inside parenthesis, only indent one 'shiftwidth'.
      let pp = searchpair('(\|{\|\[', '', ')\|}\|\]', 'bW',
	  \ "line('.') < " . (a:lnum - s:maxoff) . " ? dummy :"
	  \ . " synIDattr(synID(line('.'), col('.'), 1), 'name')"
	  \ . " =~ '\\(Comment\\|String\\|Char\\)$'")
      if pp > 0
	return indent(prevLnum) + shiftwidth()
      endif
      return indent(prevLnum) + shiftwidth() * 2
    endif
    if plnumstart == p
      return indent(prevLnum)
    endif
    return plindent
  endif

  let prevline = getline(prevLnum)
  let thisline = getline(a:lnum)

  " If this line is not a comment and the previous one is then move the
  " previous line further back.
  if thisline !~ '^\s*#'
    while prevline =~ '^\s*#'
      let prevLnum = prevnonblank(prevLnum - 1)
      if prevLnum == 0
	" Only comment lines before this, no indent
	return 0
      endif
      let prevline = getline(prevLnum)
      let plindent = indent(prevLnum)
    endwhile
  endif

  if prevline =~ '^\s*\(IF\|\|ELSEIF\|ELSE\|GENERATE_IF\|\|GENERATE_ELSEIF\|GENERATE_ELSE\|WHILE\|REPEAT\|TRY\|CATCH\|FINALLY\|FOR\|DO\|SWITCH\|CASE\|DEFAULT\|FUNC\|VIRTUAL\|ABSTRACT\|DEFINE\|REPLACE\|FINAL\|PROC\|MAIN\|NEW\|ENUM\|CLASS\|INTERFACE\|BITS\|MODULE\|SHARED\)\>'
    let plindent += shiftwidth()
  endif
  if thisline =~ '^\s*\(}\|ELSEIF\>\|ELSE\>\|CATCH\|FINALLY\|GENERATE_ELSEIF\>\|GENERATE_ELSE\>\|UNTIL\>\)'
    let plindent -= shiftwidth()
  endif
  if thisline =~ '^\s*\(CASE\>\|DEFAULT\>\)' && prevline !~ '^\s*SWITCH\>'
    let plindent -= shiftwidth()
  endif

  " line up continued comment that started after some code
  "   String something   # comment comment
  "                      # comment
  if a:lnum == prevLnum + 1 && thisline =~ '^\s*#' && prevline !~ '^\s*#'
    let n = match(prevline, '#')
    if n > 1
      let plindent = n
    endif
  endif

  return plindent
endfunc

let &cpo = s:cpo_save
unlet s:cpo_save