diff --git a/syntax/ats.vim b/syntax/ats.vim
index 22604b2..3bb3c5b 100644
--- a/syntax/ats.vim
+++ b/syntax/ats.vim
@@ -5,156 +5,18 @@ if !exists('main_syntax')
   let main_syntax = 'ats'
 endif
 
-" comment highlighting
-syn keyword atsTodo TODO FIXME NOTE contained
-syn match   atscCommentError display "\*/"
-syn match   atscCommentStartError display "/\*"me=e-1 contained
-syn region  atscComment matchgroup=atscCommentStart start="/\*" end="\*/" contains=atsTodo,@Spell,atscCommentStartError
-syn match   atsNestedCommentError display "\*)"
-" mercilessly ripped from d.vim
-syn region  atsNestedComment start="(\*" end="\*)" contains=atsNestedComment,atsTodo,@Spell
-syn match   atsComment "//.*" contains=atsTodo
+syn keyword atsTodo TODO FIXME contained
+syn match atsComment "\v\/\/.*$"
+syn region atsNestComment start="(\*" end="\*)" contains=atsNestComment,atsTodo,@Spell
 
-"
-" denotation highlighting
-"
+syn keyword atsKeyword staload overload with fun
 
-" special characters
-syn match   atsSpecial display contained "\\\(x\x\+\|\o\{1,3}\|.\|$\)"
-syn match   atsSpecial display contained "\\\(u\x\{4}\|U\x\{8}\)"
-syn match   atsSpecial '\\n'
-syn match   atsSpecial '@'
-" syn match   atsSpecial '#'
-syn match   atsFormat display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlL]\|ll\)\=\([bdiuoxXDOUfeEgGcCsSpn]\|\[\^\=.[^]]*\]\)" contained
-syn region  atsStringDenot start=+"+ skip=+\\\\\|\\"+ end=+"+ contains=atsSpecial,atsFormat,atsSpecial,@Spell
-syn match   atsCharDenot "'[^\\]'"
-syn match   atsCharDenot "'[^']*'" contains=atsSpecial
+syn keyword atsType void bool string char int uint charNZ strnptr Strptr0 Strptr1
 
-syn keyword atsBoolDenot true false
-syn case ignore
-syn match   atsNumbers display transparent "\<\d\|\.\d" contains=atsNumber,atsFloat,atsOctalError,atsOctal
-syn match   atsNumber display contained "\d\+\(u\=l\{0,2}\|ll\=u\)\>"
-syn match   atsNumber display contained "0x\x\+\(u\=l\{0,2}\ll\=\u\)\>"
-" flag the first zero of an octal number as something special
-syn match   atsOctal display contained "0\o\+\(u\=l\{0,2}\|ll\=u\)\>" contains=atsOctalZero
-syn match   atsFloat display contained "\d\+\.\d*\(e[-+]\=\d\+\)\="
-syn match   atsFloat display contained "\.\d\+\(e[-+]\=\d\+\)\>"
-syn match   atsFloat display contained "\d\+e[-+]\=\d\+\>"
-
-" flag an octal number with wrong digits
-syn match   atsOctalError display contained "0\o*[89]\d*"
-syn case match
-
-syn region  atsIncludes oneline start='#include' end='"' contains=atsStringDenot
-syn match   atsIdent "[A-Za-z_][0-9A-Za-z_\']*"
-
-" embedded C
-" %{^ %} %{ %} %{$ %} %{# %}
-if main_syntax !=# 'c' || exists('c')
-    syn include @atsC syntax/c.vim
-    unlet b:current_syntax
-    syn region embC start=+%{[^#$]\=+ keepend end=+%}+ contains=@atsC
-endif
-
-"
-" keyword highlighting
-"
-
-" keyword highlighting
-syn keyword atsKeyword prefix postfix infix infixl infixr op addr
-syn keyword atsKeyword staload stadef sta dynload stacst assertloc macdef
-syn keyword atsCond if then else case sif when ifcase
-syn keyword atsRepeat while
-syn keyword atsOperator mod
-syn keyword atsException exception raise try
-syn keyword atsStatement import let in where local
-syn keyword atsStatement val and fnx fun fn llam lam fix rec var of assume castfn prfun prfn
-syn keyword atsStatement begin end
-syn keyword atsTypedef typedef sortdef viewtypedef vtypedef viewdef
-syn keyword atsStructure datatype datavtype abstype dataviewtype dataprop dataview propdef absview
-syn keyword atsExternal extern implement primplmnt
-
-syn keyword atsKeyword symintr overload with
-syn keyword atsKeyword prval praxi datasort
-
-syn keyword atsSorts bool char int absprop prop type view viewtype nat absvtype absviewtype vtype
-
-syn keyword atsTypes string float double void
-
-syn match   atsSym "[%&+-\./:=@~`^|*!$#?]+\|[%&+-\./:=@~`^|*<>]+"
-
-" C preprocessor directives
-syn region  atsPreCondit start="^\s*\(%:\|#\)\s*\(if\|ifdef\|ifndef\|elif\)\>" skip="\\$" end="$" end="//"me=s-1 contains=atsComment,atsCommentError
-syn match   atsPreCondit display "^\s*\(%:\|#\)\s*\(else\|endif\)\>"
-syn region  atsCppOut start="^\s*\(%\|#\)\s*if\s\+0\+\>" end=".\@=\|$" contains=atsCppOut2
-syn region  atsCppOut2 contained start="0" end="^\s*\(%:\|#\)\s*\(endif\>\|else\>\|elif\>\)" contains=atsCppSkip
-syn region  atsCppSkip contained start="^\s*\(%:\|#\)\s*\(if\>\|ifdef\>\|print\>\|ifndef\>\)" skip="\\$" end="^\s*\(%:\|#\)\s*endif\>" contains=atsCppSkip
-syn region  atsIncluded display contained start=+"+ skip=+\\\\\|\\"+ end=+"+
-syn match   atsIncluded display contained "<[^>]*>"
-syn match   atsInclude "^\s*\(%:\|#\)\s*include\>\s*["<]" contains=atsIncluded
-syn cluster atsPreProcGroup contains=atsPreCondit,atsIncluded,atsInclude,atsDefine,atsCppOut,atsCppOut2,atsCppSkip
-syn region  atsDefine matchgroup=atsPreCondit start="\s*\(%:\|#\)\s*\(define\|undef\)\>" skip="\\$" end="$"
-syn region  atsPreProc matchgroup=atsPreCondit start="^\s*\(%:\|#\)\s*\(pragma\>\|line\>warning\>\|warn\>\|error\>\)" skip="\\$" end="$" keepend
-
-"
-" linking
-"
-
-" don't use standard HiLink, it won't work with included syntax files
-command! -nargs=+ AtsHiLink hi def link <args>
-
-" includes
-AtsHiLink atsIncludes Special
-AtsHiLink atsSpecial Special
-
-" comments
-AtsHiLink atsCommentStart atsComment
-AtsHiLink atsNestedComment Comment
-AtsHiLink atscCommentStart Comment
-AtsHiLink atscComment Comment
-AtsHiLink atsComment Comment
-" delimiters
-AtsHiLink atsEncl Keyword
-" constants and denotations
-AtsHiLink atsBoolDenot   Boolean
-AtsHiLink atsCharsDenot  String
-AtsHiLink atsCharDenot   Character
-AtsHiLink atsStringDenot String
-AtsHiLink atsNumber Number
-AtsHiLink atsOctal Number
-AtsHiLink atsOctalZero PreProc " link this to Error if you want
-AtsHiLink atsFloat Float
-AtsHiLink atsOctalError atsError
-" identifiers
-AtsHiLink atsIdent Identifier
-" various keywords
-AtsHiLink atsKey Keyword
-AtsHiLink atsOperator Operator
-AtsHiLink atsCond Conditional
-AtsHiLink atsRepeat Repeat
-AtsHiLink atsException Exception
-AtsHiLink atsStatement Statement
-AtsHiLink atsKeyword Statement
-AtsHiLink atsTypedef Typedef
-AtsHiLink atsStructure Structure
-AtsHiLink atsExternal StorageClass
-AtsHiLink atsTypes Type
-AtsHiLink atsSorts Type
-AtsHiLink atsSym Operator
-AtsHiLink atsEncl Keyword
-" embedded C
-AtsHiLink embC Special
-
-AtsHiLink atsPreProc PreProc
-
-AtsHiLink atsCommentError atsError
-AtsHiLink atscCommentStartError atsError
-AtsHiLink atscCommentError atsError
-AtsHiLink atsNestedCommentError atsError
-AtsHiLink atsError Error
-AtsHiLink atsAllErrs Error
-
-delcommand AtsHiLink
+highlight link atsComment Comment
+highlight link atsNestComment Comment
+highlight link atsKeyword Keyword
+highlight link atsType Type
 
 let b:current_syntax = 'ats'