Op 6-9-2020 om 10:07 schreef Steffen Märcker:
Maybe this is a naive question, but can you just split the task into the
following two?
1. Check whether whether the string is syntactically an ISBN number.
This can be done, e.g., using a regex.
2. Check the the check character.
Calculate the check character from the (now to be known) syntactically
valid string.
ISBNValidator>>isValidISBN: aString
^(self isSyntacticallyValid: aString) and: [self isCheckCharacterValid:
aString]
Kind regards,
Steffen nder if the code will not be too big. I learned that it is good
Sorry to respond not earlier but your respons seems to be in the spam
folder of my provider.
I could do that but if very bad in regex so I do not know a regex which
van validate 123456789 or 123-456-78-9
Roelof
