Re: [xml-dev] It is okay for things to break in the future!

[Michael Kay <mike@saxonica.com>]

> 
> To stick with the telephone number example (though I'm not sure it's the best one), you _could_ design a system which would deal with arbitrary-length phone numbers, but it would be more complicated than one which presumed all numbers had 12 digits, or which normalised input to 12 digits.  You'd be more likely to get the more general version wrong, it wouldn't be tested as thoroughly, and it wouldn't have any payoff, because you would expect to interoperate with other systems that presumed only 12 digits.  Thus, as a matter of engineering good taste, you might well decide against the generalised behaviour, and to hard-code 12 telephone digits in your system.

UK phone numbers are variable-length.

Michael Kay
Saxonica