runtime/autoload/dist/ft.vim

" Vim functions for file type detection
"
" Maintainer:	Bram Moolenaar <Bram@vim.org>
" Last Change:	2020 Aug 17

" These functions are moved here from runtime/filetype.vim to make startup
" faster.

" Line continuation is used here, remove 'C' from 'cpoptions'
let s:cpo_save = &cpo
set cpo&vim

func dist#ft#Check_inp()
  if getline(1) =~ '^\*'
    setf abaqus
  else
    let n = 1
    if line("$") > 500
      let nmax = 500
    else
      let nmax = line("$")
    endif
    while n <= nmax
      if getline(n) =~? "^header surface data"
	setf trasys
	break
      endif
      let n = n + 1
    endwhile
  endif
endfunc

" This function checks for the kind of assembly that is wanted by the user, or
" can be detected from the first five lines of the file.
func dist#ft#FTasm()
  " make sure b:asmsyntax exists
  if !exists("b:asmsyntax")
    let b:asmsyntax = ""
  endif

  if b:asmsyntax == ""
    call dist#ft#FTasmsyntax()
  endif

  " if b:asmsyntax still isn't set, default to asmsyntax or GNU
  if b:asmsyntax == ""
    if exists("g:asmsyntax")
      let b:asmsyntax = g:asmsyntax
    else
      let b:asmsyntax = "asm"
    endif
  endif

  exe "setf " . fnameescape(b:asmsyntax)
endfunc

func dist#ft#FTasmsyntax()
  " see if file contains any asmsyntax=foo overrides. If so, change
  " b:asmsyntax appropriately
  let head = " ".getline(1)." ".getline(2)." ".getline(3)." ".getline(4).
	\" ".getline(5)." "
  let match = matchstr(head, '\sasmsyntax=\zs[a-zA-Z0-9]\+\ze\s')
  if match != ''
    let b:asmsyntax = match
  elseif ((head =~? '\.title') || (head =~? '\.ident') || (head =~? '\.macro') || (head =~? '\.subtitle') || (head =~? '\.library'))
    let b:asmsyntax = "vmasm"
  endif
endfunc

" Check if one of the first five lines contains "VB_Name".  In that case it is
" probably a Visual Basic file.  Otherwise it's assumed to be "alt" filetype.
func dist#ft#FTVB(alt)
  if getline(1).getline(2).getline(3).getline(4).getline(5) =~? 'VB_Name\|Begin VB\.\(Form\|MDIForm\|UserControl\)'
    setf vb
  else
    exe "setf " . a:alt
  endif
endfunc

func dist#ft#FTbtm()
  if exists("g:dosbatch_syntax_for_btm") && g:dosbatch_syntax_for_btm
    setf dosbatch
  else
    setf btm
  endif
endfunc

func dist#ft#BindzoneCheck(default)
  if getline(1).getline(2).getline(3).getline(4) =~ '^; <<>> DiG [0-9.]\+.* <<>>\|$ORIGIN\|$TTL\|IN\s\+SOA'
    setf bindzone
  elseif a:default != ''
    exe 'setf ' . a:default
  endif
endfunc

func dist#ft#FTlpc()
  if exists("g:lpc_syntax_for_c")
    let lnum = 1
    while lnum <= 12
      if getline(lnum) =~# '^\(//\|inherit\|private\|protected\|nosave\|string\|object\|mapping\|mixed\)'
	setf lpc
	return
      endif
      let lnum = lnum + 1
    endwhile
  endif
  setf c
endfunc

func dist#ft#FTheader()
  if match(getline(1, min([line("$"), 200])), '^@\(interface\|end\|class\)') > -1
    if exists("g:c_syntax_for_h")
      setf objc
    else
      setf objcpp
    endif
  elseif exists("g:c_syntax_for_h")
    setf c
  elseif exists("g:ch_syntax_for_h")
    setf ch
  else
    setf cpp
  endif
endfunc

" This function checks if one of the first ten lines start with a '@'.  In
" that case it is probably a change file.
" If the first line starts with # or ! it's probably a ch file.
" If a line has "main", "include", "//" or "/*" it's probably ch.
" Otherwise CHILL is assumed.
func dist#ft#FTchange()
  let lnum = 1
  while lnum <= 10
    if getline(lnum)[0] == '@'
      setf change
      return
    endif
    if lnum == 1 && (getline(1)[0] == '#' || getline(1)[0] == '!')
      setf ch
      return
    endif
    if getline(lnum) =~ "MODULE"
      setf chill
      return
    endif
    if getline(lnum) =~ 'main\s*(\|#\s*include\|//'
      setf ch
      return
    endif
    let lnum = lnum + 1
  endwhile
  setf chill
endfunc

func dist#ft#FTent()
  " This function checks for valid cl syntax in the first five lines.
  " Look for either an opening comment, '#', or a block start, '{".
  " If not found, assume SGML.
  let lnum = 1
  while lnum < 6
    let line = getline(lnum)
    if line =~ '^\s*[#{]'
      setf cl
      return
    elseif line !~ '^\s*$'
      " Not a blank line, not a comment, and not a block start,
      " so doesn't look like valid cl code.
      break
    endif
    let lnum = lnum + 1
  endw
  setf dtd
endfunc

func dist#ft#ExCheck()
  let lines = getline(1, min([line("$"), 100]))
  if exists('g:filetype_euphoria')
    exe 'setf ' . g:filetype_euphoria
  elseif match(lines, '^--\|^ifdef\>\|^include\>') > -1
    setf euphoria3
  else
    setf elixir
  endif
endfunc

func dist#ft#EuphoriaCheck()
  if exists('g:filetype_euphoria')
    exe 'setf ' . g:filetype_euphoria
  else
    setf euphoria3
  endif
endfunc

func dist#ft#DtraceCheck()
  let lines = getline(1, min([line("$"), 100]))
  if match(lines, '^module\>\|^import\>') > -1
    " D files often start with a module and/or import statement.
    setf d
  elseif match(lines, '^#!\S\+dtrace\|#pragma\s\+D\s\+option\|:\S\{-}:\S\{-}:') > -1
    setf dtrace
  else
    setf d
  endif
endfunc

func dist#ft#FTe()
  if exists('g:filetype_euphoria')
    exe 'setf ' . g:filetype_euphoria
  else
    let n = 1
    while n < 100 && n <= line("$")
      if getline(n) =~ "^\\s*\\(<'\\|'>\\)\\s*$"
	setf specman
	return
      endif
      let n = n + 1
    endwhile
    setf eiffel
  endif
endfunc

" Distinguish between HTML, XHTML and Django
func dist#ft#FThtml()
  let n = 1
  while n < 10 && n <= line("$")
    if getline(n) =~ '\<DTD\s\+XHTML\s'
      setf xhtml
      return
    endif
    if getline(n) =~ '{%\s*\(extends\|block\|load\)\>\|{#\s\+'
      setf htmldjango
      return
    endif
    let n = n + 1
  endwhile
  setf FALLBACK html
endfunc

" Distinguish between standard IDL and MS-IDL
func dist#ft#FTidl()
  let n = 1
  while n < 50 && n <= line("$")
    if getline(n) =~ '^\s*import\s\+"\(unknwn\|objidl\)\.idl"'
      setf msidl
      return
    endif
    let n = n + 1
  endwhile
  setf idl
endfunc

" Distinguish between "default" and Cproto prototype file. */
func dist#ft#ProtoCheck(default)
  " Cproto files have a comment in the first line and a function prototype in
  " the second line, it always ends in ";".  Indent files may also have
  " comments, thus we can't match comments to see the difference.
  " IDL files can have a single ';' in the second line, require at least one
  " chacter before the ';'.
  if getline(2) =~ '.;$'
    setf cpp
  else
    exe 'setf ' . a:default
  endif
endfunc

func dist#ft#FTm()
  if exists("g:filetype_m")
    exe "setf " . g:filetype_m
    return
  endif

  " excluding end(for|function|if|switch|while) common to Murphi
  let octave_block_terminators = '\<end\%(_try_catch\|classdef\|enumeration\|events\|methods\|parfor\|properties\)\>'

  let n = 1
  let saw_comment = 0 " Whether we've seen a multiline comment leader.
  while n < 100
    let line = getline(n)
    if line =~ '^\s*/\*'
      " /* ... */ is a comment in Objective C and Murphi, so we can't conclude
      " it's either of them yet, but track this as a hint in case we don't see
      " anything more definitive.
      let saw_comment = 1
    endif
    if line =~ '^\s*\(#\s*\(include\|import\)\>\|@import\>\|//\)'
      setf objc
      return
    endif
    if line =~ '^\s*\%(#\|%!\)' || line =~ '^\s*unwind_protect\>' ||
	  \ line =~ '\%(^\|;\)\s*' .. octave_block_terminators
      setf octave
      return
    endif
    " TODO: could be Matlab or Octave
    if line =~ '^\s*%'
      setf matlab
      return
    endif
    if line =~ '^\s*(\*'
      setf mma
      return
    endif
    if line =~ '^\c\s*\(\(type\|var\)\>\|--\)'
      setf murphi
      return
    endif
    let n = n + 1
  endwhile

  if saw_comment
    " We didn't see anything definitive, but this looks like either Objective C
    " or Murphi based on the comment leader. Assume the former as it is more
    " common.
    setf objc
  else
    " Default is Matlab
    setf matlab
  endif
endfunc

func dist#ft#FTmms()
  let n = 1
  while n < 20
    let line = getline(n)
    if line =~ '^\s*\(%\|//\)' || line =~ '^\*'
      setf mmix
      return
    endif
    if line =~ '^\s*#'
      setf make
      return
    endif
    let n = n + 1
  endwhile
  setf mmix
endfunc

" This function checks if one of the first five lines start with a dot.  In
" that case it is probably an nroff file: 'filetype' is set and 1 is returned.
func dist#ft#FTnroff()
  if getline(1)[0] . getline(2)[0] . getline(3)[0] . getline(4)[0] . getline(5)[0] =~ '\.'
    setf nroff
    return 1
  endif
  return 0
endfunc

func dist#ft#FTmm()
  let n = 1
  while n < 20
    let line = getline(n)
    if line =~ '^\s*\(#\s*\(include\|import\)\>\|@import\>\|/\*\)'
      setf objcpp
      return
    endif
    let n = n + 1
  endwhile
  setf nroff
endfunc

func dist#ft#FTpl()
  if exists("g:filetype_pl")
    exe "setf " . g:filetype_pl
  else
    " recognize Prolog by specific text in the first non-empty line
    " require a blank after the '%' because Perl uses "%list" and "%translate"
    let l = getline(nextnonblank(1))
    if l =~ '\<prolog\>' || l =~ '^\s*\(%\+\(\s\|$\)\|/\*\)' || l =~ ':-'
      setf prolog
    else
      setf perl
    endif
  endif
endfunc

func dist#ft#FTinc()
  if exists("g:filetype_inc")
    exe "setf " . g:filetype_inc
  else
    let lines = getline(1).getline(2).getline(3)
    if lines =~? "perlscript"
      setf aspperl
    elseif lines =~ "<%"
      setf aspvbs
    elseif lines =~ "<?"
      setf php
    " Pascal supports // comments but they're vary rarely used for file
    " headers so assume POV-Ray
    elseif lines =~ '^\s*\%({\|(\*\)' || lines =~? s:ft_pascal_keywords
      setf pascal
    else
      call dist#ft#FTasmsyntax()
      if exists("b:asmsyntax")
	exe "setf " . fnameescape(b:asmsyntax)
      else
	setf pov
      endif
    endif
  endif
endfunc

func dist#ft#FTprogress_cweb()
  if exists("g:filetype_w")
    exe "setf " . g:filetype_w
    return
  endif
  if getline(1) =~ '&ANALYZE' || getline(3) =~ '&GLOBAL-DEFINE'
    setf progress
  else
    setf cweb
  endif
endfunc

func dist#ft#FTprogress_asm()
  if exists("g:filetype_i")
    exe "setf " . g:filetype_i
    return
  endif
  " This function checks for an assembly comment the first ten lines.
  " If not found, assume Progress.
  let lnum = 1
  while lnum <= 10 && lnum < line('$')
    let line = getline(lnum)
    if line =~ '^\s*;' || line =~ '^\*'
      call dist#ft#FTasm()
      return
    elseif line !~ '^\s*$' || line =~ '^/\*'
      " Not an empty line: Doesn't look like valid assembly code.
      " Or it looks like a Progress /* comment
      break
    endif
    let lnum = lnum + 1
  endw
  setf progress
endfunc

let s:ft_pascal_comments = '^\s*\%({\|(\*\|//\)'
let s:ft_pascal_keywords = '^\s*\%(program\|unit\|library\|uses\|begin\|procedure\|function\|const\|type\|var\)\>'

func dist#ft#FTprogress_pascal()
  if exists("g:filetype_p")
    exe "setf " . g:filetype_p
    return
  endif
  " This function checks for valid Pascal syntax in the first ten lines.
  " Look for either an opening comment or a program start.
  " If not found, assume Progress.
  let lnum = 1
  while lnum <= 10 && lnum < line('$')
    let line = getline(lnum)
    if line =~ s:ft_pascal_comments || line =~? s:ft_pascal_keywords
      setf pascal
      return
    elseif line !~ '^\s*$' || line =~ '^/\*'
      " Not an empty line: Doesn't look like valid Pascal code.
      " Or it looks like a Progress /* comment
      break
    endif
    let lnum = lnum + 1
  endw
  setf progress
endfunc

func dist#ft#FTpp()
  if exists("g:filetype_pp")
    exe "setf " . g:filetype_pp
  else
    let line = getline(nextnonblank(1))
    if line =~ s:ft_pascal_comments || line =~? s:ft_pascal_keywords
      setf pascal
    else
      setf puppet
    endif
  endif
endfunc

func dist#ft#FTr()
  let max = line("$") > 50 ? 50 : line("$")

  for n in range(1, max)
    " Rebol is easy to recognize, check for that first
    if getline(n) =~? '\<REBOL\>'
      setf rebol
      return
    endif
  endfor

  for n in range(1, max)
    " R has # comments
    if getline(n) =~ '^\s*#'
      setf r
      return
    endif
    " Rexx has /* comments */
    if getline(n) =~ '^\s*/\*'
      setf rexx
      return
    endif
  endfor

  " Nothing recognized, use user default or assume Rexx
  if exists("g:filetype_r")
    exe "setf " . g:filetype_r
  else
    " Rexx used to be the default, but R appears to be much more popular.
    setf r
  endif
endfunc

func dist#ft#McSetf()
  " Rely on the file to start with a comment.
  " MS message text files use ';', Sendmail files use '#' or 'dnl'
  for lnum in range(1, min([line("$"), 20]))
    let line = getline(lnum)
    if line =~ '^\s*\(#\|dnl\)'
      setf m4  " Sendmail .mc file
      return
    elseif line =~ '^\s*;'
      setf msmessages  " MS Message text file
      return
    endif
  endfor
  setf m4  " Default: Sendmail .mc file
endfunc

" Called from filetype.vim and scripts.vim.
func dist#ft#SetFileTypeSH(name)
  if did_filetype()
    " Filetype was already detected
    return
  endif
  if expand("<amatch>") =~ g:ft_ignore_pat
    return
  endif
  if a:name =~ '\<csh\>'
    " Some .sh scripts contain #!/bin/csh.
    call dist#ft#SetFileTypeShell("csh")
    return
  elseif a:name =~ '\<tcsh\>'
    " Some .sh scripts contain #!/bin/tcsh.
    call dist#ft#SetFileTypeShell("tcsh")
    return
  elseif a:name =~ '\<zsh\>'
    " Some .sh scripts contain #!/bin/zsh.
    call dist#ft#SetFileTypeShell("zsh")
    return
  elseif a:name =~ '\<ksh\>'
    let b:is_kornshell = 1
    if exists("b:is_bash")
      unlet b:is_bash
    endif
    if exists("b:is_sh")
      unlet b:is_sh
    endif
  elseif exists("g:bash_is_sh") || a:name =~ '\<bash\>' || a:name =~ '\<bash2\>'
    let b:is_bash = 1
    if exists("b:is_kornshell")
      unlet b:is_kornshell
    endif
    if exists("b:is_sh")
      unlet b:is_sh
    endif
  elseif a:name =~ '\<sh\>'
    let b:is_sh = 1
    if exists("b:is_kornshell")
      unlet b:is_kornshell
    endif
    if exists("b:is_bash")
      unlet b:is_bash
    endif
  endif
  call dist#ft#SetFileTypeShell("sh")
endfunc

" For shell-like file types, check for an "exec" command hidden in a comment,
" as used for Tcl.
" Also called from scripts.vim, thus can't be local to this script.
func dist#ft#SetFileTypeShell(name)
  if did_filetype()
    " Filetype was already detected
    return
  endif
  if expand("<amatch>") =~ g:ft_ignore_pat
    return
  endif
  let l = 2
  while l < 20 && l < line("$") && getline(l) =~ '^\s*\(#\|$\)'
    " Skip empty and comment lines.
    let l = l + 1
  endwhile
  if l < line("$") && getline(l) =~ '\s*exec\s' && getline(l - 1) =~ '^\s*#.*\\$'
    " Found an "exec" line after a comment with continuation
    let n = substitute(getline(l),'\s*exec\s\+\([^ ]*/\)\=', '', '')
    if n =~ '\<tclsh\|\<wish'
      setf tcl
      return
    endif
  endif
  exe "setf " . a:name
endfunc

func dist#ft#CSH()
  if did_filetype()
    " Filetype was already detected
    return
  endif
  if exists("g:filetype_csh")
    call dist#ft#SetFileTypeShell(g:filetype_csh)
  elseif &shell =~ "tcsh"
    call dist#ft#SetFileTypeShell("tcsh")
  else
    call dist#ft#SetFileTypeShell("csh")
  endif
endfunc

let s:ft_rules_udev_rules_pattern = '^\s*\cudev_rules\s*=\s*"\([^"]\{-1,}\)/*".*'
func dist#ft#FTRules()
  let path = expand('<amatch>:p')
  if path =~ '/\(etc/udev/\%(rules\.d/\)\=.*\.rules\|\%(usr/\)\=lib/udev/\%(rules\.d/\)\=.*\.rules\)$'
    setf udevrules
    return
  endif
  if path =~ '^/etc/ufw/'
    setf conf  " Better than hog
    return
  endif
  if path =~ '^/\(etc\|usr/share\)/polkit-1/rules\.d'
    setf javascript
    return
  endif
  try
    let config_lines = readfile('/etc/udev/udev.conf')
  catch /^Vim\%((\a\+)\)\=:E484/
    setf hog
    return
  endtry
  let dir = expand('<amatch>:p:h')
  for line in config_lines
    if line =~ s:ft_rules_udev_rules_pattern
      let udev_rules = substitute(line, s:ft_rules_udev_rules_pattern, '\1', "")
      if dir == udev_rules
	setf udevrules
      endif
      break
    endif
  endfor
  setf hog
endfunc

func dist#ft#SQL()
  if exists("g:filetype_sql")
    exe "setf " . g:filetype_sql
  else
    setf sql
  endif
endfunc

" If the file has an extension of 't' and is in a directory 't' or 'xt' then
" it is almost certainly a Perl test file.
" If the first line starts with '#' and contains 'perl' it's probably a Perl
" file.
" (Slow test) If a file contains a 'use' statement then it is almost certainly
" a Perl file.
func dist#ft#FTperl()
  let dirname = expand("%:p:h:t")
  if expand("%:e") == 't' && (dirname == 't' || dirname == 'xt')
    setf perl
    return 1
  endif
  if getline(1)[0] == '#' && getline(1) =~ 'perl'
    setf perl
    return 1
  endif
  let save_cursor = getpos('.')
  call cursor(1,1)
  let has_use = search('^use\s\s*\k', 'c', 30)
  call setpos('.', save_cursor)
  if has_use
    setf perl
    return 1
  endif
  return 0
endfunc

" Choose context, plaintex, or tex (LaTeX) based on these rules:
" 1. Check the first line of the file for "%&<format>".
" 2. Check the first 1000 non-comment lines for LaTeX or ConTeXt keywords.
" 3. Default to "plain" or to g:tex_flavor, can be set in user's vimrc.
func dist#ft#FTtex()
  let firstline = getline(1)
  if firstline =~ '^%&\s*\a\+'
    let format = tolower(matchstr(firstline, '\a\+'))
    let format = substitute(format, 'pdf', '', '')
    if format == 'tex'
      let format = 'latex'
    elseif format == 'plaintex'
      let format = 'plain'
    endif
  elseif expand('%') =~ 'tex/context/.*/.*.tex'
    let format = 'context'
  else
    " Default value, may be changed later:
    let format = exists("g:tex_flavor") ? g:tex_flavor : 'plain'
    " Save position, go to the top of the file, find first non-comment line.
    let save_cursor = getpos('.')
    call cursor(1,1)
    let firstNC = search('^\s*[^[:space:]%]', 'c', 1000)
    if firstNC " Check the next thousand lines for a LaTeX or ConTeXt keyword.
      let lpat = 'documentclass\>\|usepackage\>\|begin{\|newcommand\>\|renewcommand\>'
      let cpat = 'start\a\+\|setup\a\+\|usemodule\|enablemode\|enableregime\|setvariables\|useencoding\|usesymbols\|stelle\a\+\|verwende\a\+\|stel\a\+\|gebruik\a\+\|usa\a\+\|imposta\a\+\|regle\a\+\|utilisemodule\>'
      let kwline = search('^\s*\\\%(' . lpat . '\)\|^\s*\\\(' . cpat . '\)',
			      \ 'cnp', firstNC + 1000)
      if kwline == 1	" lpat matched
	let format = 'latex'
      elseif kwline == 2	" cpat matched
	let format = 'context'
      endif		" If neither matched, keep default set above.
      " let lline = search('^\s*\\\%(' . lpat . '\)', 'cn', firstNC + 1000)
      " let cline = search('^\s*\\\%(' . cpat . '\)', 'cn', firstNC + 1000)
      " if cline > 0
      "   let format = 'context'
      " endif
      " if lline > 0 && (cline == 0 || cline > lline)
      "   let format = 'tex'
      " endif
    endif " firstNC
    call setpos('.', save_cursor)
  endif " firstline =~ '^%&\s*\a\+'

  " Translation from formats to file types.  TODO:  add AMSTeX, RevTex, others?
  if format == 'plain'
    setf plaintex
  elseif format == 'context'
    setf context
  else " probably LaTeX
    setf tex
  endif
  return
endfunc

func dist#ft#FTxml()
  let n = 1
  while n < 100 && n <= line("$")
    let line = getline(n)
    " DocBook 4 or DocBook 5.
    let is_docbook4 = line =~ '<!DOCTYPE.*DocBook'
    let is_docbook5 = line =~ ' xmlns="http://docbook.org/ns/docbook"'
    if is_docbook4 || is_docbook5
      let b:docbk_type = "xml"
      if is_docbook5
	let b:docbk_ver = 5
      else
	let b:docbk_ver = 4
      endif
      setf docbk
      return
    endif
    if line =~ 'xmlns:xbl="http://www.mozilla.org/xbl"'
      setf xbl
      return
    endif
    let n += 1
  endwhile
  setf xml
endfunc

func dist#ft#FTy()
  let n = 1
  while n < 100 && n <= line("$")
    let line = getline(n)
    if line =~ '^\s*%'
      setf yacc
      return
    endif
    if getline(n) =~ '^\s*\(#\|class\>\)' && getline(n) !~ '^\s*#\s*include'
      setf racc
      return
    endif
    let n = n + 1
  endwhile
  setf yacc
endfunc

func dist#ft#Redif()
  let lnum = 1
  while lnum <= 5 && lnum < line('$')
    if getline(lnum) =~ "^\ctemplate-type:"
      setf redif
      return
    endif
    let lnum = lnum + 1
  endwhile
endfunc


" Restore 'cpoptions'
let &cpo = s:cpo_save
unlet s:cpo_save