For anyone editing kidl files, here's a reasonable kidl.vim
You'll probably want to put this at the end of your kidl files:
<!-- vim: set syntax=kidl: -->

Cheers,
Rik

-------- kut here ---------
" Vim syntax file
" Language:     kidl
" Maintainer:   Rik Hemsley <rik@kde.org>
" Last change:  Oct 25 1999

syn clear
syn case ignore

syn match   kidlSpecial "&[^;]*;"

syn keyword kidlArg     contained file name type qual
syn keyword kidlTagName contained include class super func ret arg dcop-idl

syn region  kidlValue   start=/"/     end=/"/ contains=kidlSpecial
syn region  kidlEndTag  start=+</+    end=/>/ contains=kidlTagName
syn region  kidlTag     start=+<[^/]+ end=/>/ contains=kidlTagName,kidlArg,kidlValue

syn region kidlComment  start=/<!--/ end=/-->/
syn region kidlPreProc  start=/<!doctype/ end=/>/

hi link kidlTag     Statement
hi link kidlEndTag  Statement
hi link kidlTagName Identifier
hi link kidlArg     Type
hi link kidlValue   Constant
hi link kidlPreProc PreProc
hi link kidlSpecial Special
hi link kidlComment Comment

let b:current_syntax = "kidl"
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