new file mode 100644
--- /dev/null
+++ b/runtime/syntax/rnc.vim
@@ -0,0 +1,94 @@
+" Vim syntax file
+" Language:	    Relax NG compact syntax
+" Maintainer:	    Nikolai Weibull <source@pcppopper.org>
+" URL:		    http://www.pcppopper.org/vim/syntax/pcp/rnc/
+" Latest Revision:  2004-05-22
+" arch-tag:	    061ee0a2-9efa-4e2a-b1a9-14cf5172d645
+
+if version < 600
+  syntax clear
+elseif exists("b:current_syntax")
+  finish
+endif
+
+" Set iskeyword since we need `-' (and potentially others) in keywords.
+" For version 5.x: Set it globally
+" For version 6.x: Set it locally
+if version >= 600
+  command -nargs=1 SetIsk setlocal iskeyword=<args>
+else
+  command -nargs=1 SetIsk set iskeyword=<args>
+endif
+SetIsk @,48-57,_,-,.
+delcommand SetIsk
+
+" Todo
+syn keyword rncTodo	    contained TODO FIXME XXX NOTE
+
+" Comments
+syn region  rncComment	    matchgroup=rncComment start='^\s*#' end='$' contains=rncTodo
+
+" Operators
+syn match   rncOperator	    '[-|,&+?*~]'
+syn match   rncOperator	    '\%(|&\)\=='
+syn match   rncOperator	    '>>'
+
+" Namespaces
+syn match   rncNamespace    '\<\k\+:'
+
+" Quoted Identifier
+syn match   rncQuoted	    '\\\k\+\>'
+
+" Special Characters
+syn match   rncSpecial	    '\\x{\x\+}'
+
+" Annotations
+syn region Annotation	    transparent start='\[' end='\]' contains=ALLBUT,rncComment,rncTodo
+
+" Literals
+syn region  rncLiteral	    matchgroup=rncLiteral oneline start=+"+ end=+"+ contains=rncSpecial
+syn region  rncLiteral	    matchgroup=rncLiteral oneline start=+'+ end=+'+
+syn region  rncLiteral	    matchgroup=rncLiteral start=+"""+ end=+"""+ contains=rncSpecial
+syn region  rncLiteral	    matchgroup=rncLiteral start=+'''+ end=+'''+
+
+" Delimiters
+syn match   rncDelimiter    '[{},()]'
+
+" Keywords
+syn keyword rncKeyword	    datatypes default div empty external grammar
+syn keyword rncKeyword	    include inherit list mixed name namespace
+syn keyword rncKeyword	    notAllowed parent start string text token
+
+" Identifiers
+syn match   rncIdentifier   '\k\+\_s*\%(=\|&=\||=\)\@=' nextgroup=rncOperator
+syn keyword rncKeyword	    nextgroup=rncIdName skipwhite skipempty element attribute
+syn match   rncIdentifier   contained '\k\+'
+
+" 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_rnc_syn_inits")
+  if version < 508
+    let did_rnc_syn_inits = 1
+    command -nargs=+ HiLink hi link <args>
+  else
+    command -nargs=+ HiLink hi def link <args>
+  endif
+
+  HiLink rncTodo	Todo
+  HiLink rncComment	Comment
+  HiLink rncOperator	Operator
+  HiLink rncNamespace	Identifier
+  HiLink rncQuoted	Special
+  HiLink rncSpecial	SpecialChar
+  HiLink rncLiteral	String
+  HiLink rncDelimiter	Delimiter
+  HiLink rncKeyword	Keyword
+  HiLink rncIdentifier	Identifier
+
+  delcommand HiLink
+endif
+
+let b:current_syntax = "rnc"
+
+" vim: set sts=2 sw=2: