" Vim syntax file
" Language:	Plan 9 rc shell
" Maintainer:	Noah

if version < 600
  syntax clear
elseif exists("b:current_syntax")
  finish
endif

syn iskeyword @,48-57,_,*
syn case match

syn cluster rcshTop contains=rcshComment,rcshString,rcshBackquote,rcshBlock,rcshVar,rcshCountVar,rcshFlatVar,rcshSubscript,rcshRedir,rcshPipe,rcshConditional,rcshOperator,rcshDelimiter,rcshKeyword,rcshBuiltin,rcshPatternClass,rcshPattern,rcshShebang,rcshContinuation

" rc only uses single quotes for strings. A literal quote is written as ''.
" Double quotes are deliberately not a string delimiter; $"var and $^var are
" flattening operators.
syn region rcshString		matchgroup=rcshQuote keepend extend start="'" skip="''" end="'" contains=rcshQuoteQuote,@Spell
syn match  rcshQuoteQuote	contained "''"

syn match rcshComment		"#.*" contains=rcshTodo,@Spell extend
syn keyword rcshTodo		contained TODO TBD FIXME XXX NOTE BUG WARNING DEBUG OPTIMIZATION WORKAROUND
syn match rcshShebang		"^#!.*\<\%(env\s\+\)\?rc\>\%(\s\+.*\)\?$" contains=rcshOption
syn match rcshOption		contained "\s-\S\+"

" A backslash is ordinary in rc, except before a newline.
syn match rcshContinuation	"\\\n"

syn keyword rcshKeyword		if else for in while switch case fn
syn keyword rcshBuiltin		break builtin cd continue echo eval exec exit flag limit newpgrp return shift umask wait whatis
syn match   rcshBuiltin		"\(^\|[ \t;|&(){}]\)\zs\.\ze\($\|[ \t;|&(){}]\)"

syn match rcshConditional	"&&\|||"
syn match rcshPipe		"|\%(\[\d\+\%([=]\d*\)\?\]\)\?"
syn match rcshRedir		"\%(>>\|<<<\|<<\|<\|>\)\%(\[\d\+\%([=]\d*\)\?\]\)\?"
syn match rcshOperator		"[=^~!@`$]"
syn match rcshDelimiter		"[;&()]"

syn region rcshBlock		matchgroup=rcshDelimiter keepend extend start="{" end="}" contains=@rcshTop,@NoSpell
syn region rcshBackquote	matchgroup=rcshBackquoteDelimiter keepend extend start="`{" end="}" contains=@rcshTop,@NoSpell
syn match  rcshBackquoteDelimiter "``"

syn match rcshCountVar		"\$#\%([A-Za-z0-9_*]\+\|'[^']*\%(''[^']*\)*'\)"
syn match rcshFlatVar		"\$[\^"]\%([A-Za-z0-9_*]\+\|'[^']*\%(''[^']*\)*'\)"
syn match rcshVar		"\$[A-Za-z0-9_*]\+"
syn match rcshVar		"\$\ze'"
syn region rcshSubscript	matchgroup=rcshDelimiter keepend extend start="\%(\$[#\^"]\?\)\?[A-Za-z0-9_*]\+(" end=")" contains=@rcshTop,@NoSpell

syn region rcshPatternClass	matchgroup=rcshPattern keepend extend oneline start="\[^\?" end="\]" contains=rcshPatternRange
syn match  rcshPatternRange	contained "\(\[^\?\)\@<!-\]\@!"
syn match  rcshPattern		"[*?]"

if version >= 508 || !exists("did_rcsh_syn_inits")
  if version < 508
    let did_rcsh_syn_inits = 1
    command -nargs=+ HiLink hi link <args>
  else
    command -nargs=+ HiLink hi def link <args>
  endif

  HiLink rcshBackquote		PreProc
  HiLink rcshBackquoteDelimiter	Include
  HiLink rcshBuiltin		Statement
  HiLink rcshComment		Comment
  HiLink rcshConditional	Conditional
  HiLink rcshContinuation	Special
  HiLink rcshCountVar		Special
  HiLink rcshDelimiter		Delimiter
  HiLink rcshFlatVar		Special
  HiLink rcshKeyword		Keyword
  HiLink rcshOperator		Operator
  HiLink rcshOption		PreProc
  HiLink rcshPattern		SpecialChar
  HiLink rcshPatternRange	SpecialChar
  HiLink rcshPipe		Type
  HiLink rcshQuote		String
  HiLink rcshQuoteQuote		SpecialChar
  HiLink rcshRedir		Type
  HiLink rcshShebang		Comment
  HiLink rcshString		String
  HiLink rcshSubscript		Identifier
  HiLink rcshTodo		Todo
  HiLink rcshVar		Identifier

  delcommand HiLink
endif

let b:current_syntax = "rcsh"