Object as function argument

[Adam D. Ruppe via Digitalmars-d-learn]

On Thursday, 5 March 2015 at 20:08:08 UTC, Chris Sperandio wrote:
> Is it clean to write this code below ?

yup. Though remember all the downsides of null - if you try to 
use a null object like accessing a member, the program will be 
terminated.