Check Sum

[Bill Marriott]

make that

  return the last char of (10 - ( x mod 10 ))

----------
function upcCheck pValue
  repeat with i = 1 to the length of pValue step 2
    add char i of pValue to x
  end repeat
  multiply x by 3
  repeat with i = 2 to the length of pValue step 2
    add char i of pValue to x
  end repeat

  return the last char of (10 - ( x mod 10 ))
end upcCheck