This does exactly what you described in your 'Usage'

alias list {
  var %x $instok($regsubex($$2,/ $+ $chr($1) $+ /gi,$+($chr(44),$chr(32))),and,-1,32)
  return $upper($left(%x,1-)) $+ $mid(%x,2,$calc($len(%x) - $iif($regex($right(%x,1),(\.|!|\?|\,)),2,1))) $+ .
}