nullable done right, was #Spec

[BLS]

The following code does not fail at compile-time or run-time because the 
if statement proves that the call is safe:
class Foo

     def bar(s as String?)
         if s  # same as "if s is not nil"
             print Utils.countChars(s, c'x')


Please note the question mark "?" on String? forces a compile time check.

--As a side note
The sample snippet is written Cobra (not Boo).. CLR NET.
Cobra's DBC is heavily influenced by D !

Bearophile could be interested; so here the link

http://cobra-language.com/docs/quality/
Bjoern