Problem Statement

For each number list of 6-digit SEDOLs, calculate and append the checksum digit.

That is, given this input: Produce this output: Check each input is correctly formed, especially with respect to valid characters allowed in a SEDOL string.

Let's start with the solution:

func: sedol(s)
   [ 1, 3, 1, 7, 3, 9 ] s 
   zipWith(#[ dup isDigit ifTrue: [ '0' - ] else: [ 'A' - 10 + ] * ]) sum
   10 mod 10 swap - 10 mod
   StringBuffer new s << swap '0' + <