Broken?

[w0rp]

I used to believe that virtual was a better default, but these 
days I think the opposite. My reasoning is that inheritance is a 
very poor tool for code reuse. The way I see it now, inheritance 
is a tool for modelling "is a" relationships and variations on 
objects, but it's bad to use it in an API as a "to implement your 
business logic inherit here" thing.

You get much better code reuse out of functions, especially with 
generic programming. (D being the number one generic language 
with its templates and CTFE.) The more loosely coupled the data 
becomes from the business logic, the higher application quality 
appears to be and the more breakage decreases. Presenting an 
interface for a library whereby the types can automatically be 
overridden is a good way to lead people into writing code that's 
going to break later and may burden the library's implementer 
with supporting something he didn't know he'd need to support. 
(e.g. in Nowak's ZIP library.)