Code:

$a=readvalue('hkcu\software\kixtart','value')
$b='aaa','bbb','ccc'
select
case @ERROR
  ; value does not exist
  $rc=writevalue('hkcu\software\kixtart','value','1234','REG_SZ')
case ascan($b,$a)
  ; value in array
case 1
  ; value not in array
endif
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There are two types of vessels, submarines and targets.