" Vim syntax file
" Language:		Autoconf M4
" Former Maintainer:	Christian Hammesr <ch@lathspell.westend.com>
" Last Change:	2018 Feb 03
" 				(patch from Yngve Inntjore Levinsen to detect AC_MSG)
" 				(patch from Khym Chanur to add @Spell)
" 				(patch from James McCoy to fix paren matching)
" 				(2025 Sep 14 patch from Damien Lejay to detect unportable +=)
" 				(2025 Sep 18 by Vim Project: fix inconsistent group name)

" Well, I actually even do not know much about m4. This explains why there
" is probably very much missing here, yet !
" But I missed good highlighting when editing my GNU autoconf/automake
" script, so I wrote this quick and dirty patch.


" quit when a syntax file was already loaded
if exists("b:current_syntax")
  finish
endif

" define the config syntax
syn match   configdelimiter "[()\[\];,]"
syn match   configoperator  "[=|&\*\+\<\>]"
syn match   configcomment   "\(dnl.*\)\|\(#.*\)" contains=configDnl,@Spell
syn match   configfunction  "\<[A-Z_][A-Z0-9_]*\>"
syn match   confignumber    "[-+]\=\<\d\+\(\.\d*\)\=\>"
syn keyword configDnl   	dnl contained
syn keyword configkeyword   if then else fi test for in do done
syn keyword configspecial   cat rm eval

" This shortens the script, see syn-ext-match..
syn region  configstring    start=+\z(["'`]\)+ skip=+\\\z1+ end=+\z1+ contains=@Spell

" Anything inside AC_MSG_TYPE([...])  and AC_MSG_TYPE(...) is a string.
syn region  configmsg matchgroup=configfunction start="AC_MSG_[A-Z]*\ze(\[" matchgroup=configdelimiter end="\])" contains=configdelimiter,@Spell
syn region  configmsg matchgroup=configfunction start="AC_MSG_[A-Z]*\ze([^[]" matchgroup=configdelimiter end=")" contains=configdelimiter,@Spell

" Help write portable shell code
syn match configPlusEq '\v\+\=' containedin=ALLBUT,configcomment

" Define the default highlighting.
" Only when an item doesn't have highlighting yet

hi def link configdelimiter Delimiter
hi def link configoperator  Operator
hi def link configcomment   Comment
hi def link configDnl  	 Comment
hi def link configfunction  Function
hi def link confignumber    Number
hi def link configkeyword   Keyword
hi def link configspecial   Special
hi def link configstring    String
hi def link configmsg       String
hi def link configPlusEq    Error


let b:current_syntax = "config"

" vim: ts=4