the javascript

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If a function can take parameters with different empty signatures then valuelessness can be caught with a call to checkParam_emptyEither().

function PRE_check_firstMidLast(first, middle, last){
  the_parameters = [first, middle, last]
  first_middle_last = [ 'EMPTY-ERROR', 'EMPTY-ERROR', 'EMPTY-ERROR' ]
  first_only = [ 'EMPTY-ERROR', 'EMPTY-OK', 'EMPTY-OK' ]
  signature = [ first_middle_last, first_only ]
  return type_czech.checkParam_emptyEither(the_parameters, signature)
}

firstMidLast = type_czech.linkUp(firstMidLast, PRE_check_firstMidLast)

function firstMidLast(first, middle, last){
}

firstMidLast('pass_a', 'middle-a', 'last-a') // pass first_middle_last
firstMidLast('pass_b', '', '')               // pass first_only

firstMidLast('', 'fail_c', '')       // fail
firstMidLast('', 'fail_d', 'last-d') // fail