runtime/indent/rhelp.vim

" Vim indent file
" Language:	R Documentation (Help), *.Rd
" Author:	Jakson Alves de Aquino <jalvesaq@gmail.com>
" Homepage:     https://github.com/jalvesaq/R-Vim-runtime
" Last Change:	Feb 25, 2023


" Only load this indent file when no other was loaded.
if exists("b:did_indent")
  finish
endif
runtime indent/r.vim
let s:RIndent = function(substitute(&indentexpr, "()", "", ""))
let b:did_indent = 1

setlocal noautoindent
setlocal nocindent
setlocal nosmartindent
setlocal nolisp
setlocal indentkeys=0{,0},:,!^F,o,O,e
setlocal indentexpr=GetCorrectRHelpIndent()

let b:undo_indent = "setl ai< cin< inde< indk< <lisp <si"

" Only define the functions once.
if exists("*GetRHelpIndent")
  finish
endif

function s:SanitizeRHelpLine(line)
  let newline = substitute(a:line, '\\\\', "x", "g")
  let newline = substitute(newline, '\\{', "x", "g")
  let newline = substitute(newline, '\\}', "x", "g")
  let newline = substitute(newline, '\\%', "x", "g")
  let newline = substitute(newline, '%.*', "", "")
  let newline = substitute(newline, '\s*$', "", "")
  return newline
endfunction

function GetRHelpIndent()

  let clnum = line(".")    " current line
  if clnum == 1
    return 0
  endif
  let cline = getline(clnum)

  if cline =~ '^\s*}\s*$'
    let i = clnum
    let bb = -1
    while bb != 0 && i > 1
      let i -= 1
      let line = s:SanitizeRHelpLine(getline(i))
      let line2 = substitute(line, "{", "", "g")
      let openb = strlen(line) - strlen(line2)
      let line3 = substitute(line2, "}", "", "g")
      let closeb = strlen(line2) - strlen(line3)
      let bb += openb - closeb
    endwhile
    return indent(i)
  endif

  if cline =~ '^\s*#ifdef\>' || cline =~ '^\s*#endif\>'
    return 0
  endif

  let lnum = clnum - 1
  let line = getline(lnum)
  if line =~ '^\s*#ifdef\>' || line =~ '^\s*#endif\>'
    let lnum -= 1
    let line = getline(lnum)
  endif
  while lnum > 1 && (line =~ '^\s*$' || line =~ '^#ifdef' || line =~ '^#endif')
    let lnum -= 1
    let line = getline(lnum)
  endwhile
  if lnum == 1
    return 0
  endif
  let line = s:SanitizeRHelpLine(line)
  let line2 = substitute(line, "{", "", "g")
  let openb = strlen(line) - strlen(line2)
  let line3 = substitute(line2, "}", "", "g")
  let closeb = strlen(line2) - strlen(line3)
  let bb = openb - closeb

  let ind = indent(lnum) + (bb * shiftwidth())

  if line =~ '^\s*}\s*$'
    let ind = indent(lnum)
  endif

  if ind < 0
    return 0
  endif

  return ind
endfunction

function GetCorrectRHelpIndent()
  let lastsection = search('^\\[a-z]*{', "bncW")
  let secname = getline(lastsection)
  if secname =~ '^\\usage{' || secname =~ '^\\examples{' || secname =~ '^\\dontshow{' || secname =~ '^\\dontrun{' || secname =~ '^\\donttest{' || secname =~ '^\\testonly{' || secname =~ '^\\method{.*}{.*}('
    return s:RIndent()
  else
    return GetRHelpIndent()
  endif
endfunction

" vim: sw=2