runtime/syntax/rcs.vim

" Vim syntax file
" Language:     RCS file
" Maintainer:   Dmitry Vasiliev <dima at hlabs dot org>
" URL:          https://github.com/hdima/vim-scripts/blob/master/syntax/rcs.vim
" Last Change:  2012-02-11
" Filenames:    *,v
" Version:      1.12

" Options:
"   rcs_folding = 1   For folding strings

" For version 5.x: Clear all syntax items.
" For version 6.x: Quit when a syntax file was already loaded.
if version < 600
  syntax clear
elseif exists("b:current_syntax")
  finish
endif

" RCS file must end with a newline.
syn match rcsEOFError   ".\%$" containedin=ALL

" Keywords.
syn keyword rcsKeyword  head branch access symbols locks strict
syn keyword rcsKeyword  comment expand date author state branches
syn keyword rcsKeyword  next desc log
syn keyword rcsKeyword  text nextgroup=rcsTextStr skipwhite skipempty

" Revision numbers and dates.
syn match rcsNumber "\<[0-9.]\+\>" display

" Strings.
if exists("rcs_folding") && has("folding")
  " Folded strings.
  syn region rcsString  matchgroup=rcsString start="@" end="@" skip="@@" fold contains=rcsSpecial
  syn region rcsTextStr matchgroup=rcsTextStr start="@" end="@" skip="@@" fold contained contains=rcsSpecial,rcsDiffLines
else
  syn region rcsString  matchgroup=rcsString start="@" end="@" skip="@@" contains=rcsSpecial
  syn region rcsTextStr matchgroup=rcsTextStr start="@" end="@" skip="@@" contained contains=rcsSpecial,rcsDiffLines
endif
syn match rcsSpecial    "@@" contained
syn match rcsDiffLines  "[da]\d\+ \d\+$" contained

" Synchronization.
syn sync clear
if exists("rcs_folding") && has("folding")
  syn sync fromstart
else
  " We have incorrect folding if following sync patterns is turned on.
  syn sync match rcsSync    grouphere rcsString "[0-9.]\+\(\s\|\n\)\+log\(\s\|\n\)\+@"me=e-1
  syn sync match rcsSync    grouphere rcsTextStr "@\(\s\|\n\)\+text\(\s\|\n\)\+@"me=e-1
endif

" Define the default highlighting.
" For version 5.7 and earlier: only when not done already.
" For version 5.8 and later: only when an item doesn't have highlighting yet.
if version >= 508 || !exists("did_rcs_syn_inits")
  if version <= 508
    let did_rcs_syn_inits = 1
    command -nargs=+ HiLink hi link <args>
  else
    command -nargs=+ HiLink hi def link <args>
  endif

  HiLink rcsKeyword     Keyword
  HiLink rcsNumber      Identifier
  HiLink rcsString      String
  HiLink rcsTextStr     String
  HiLink rcsSpecial     Special
  HiLink rcsDiffLines   Special
  HiLink rcsEOFError    Error

  delcommand HiLink
endif

let b:current_syntax = "rcs"