On Thu, Dec 10, 2015 at 12:02 AM, Dustin Wheeler <mdwhe...@ncsu.edu> wrote:
> > Both of these approaches acknowledge the problem-space of > "private collaborators". "Private collaborators" itself is perhaps > loaded terminology as it happens to reuse an already-defined concept > in this domain: `private`. The intent is to be able to express an > intimate relationship between two or more classes of object for some > justifiable domain-specific modeling reason. > Since friendship is about visibility, and "private" is already a well-defined term in discussions about visibility, I would avoid the term "private" in discussions about friendship unless you actually mean "private visibility". To me, the nut of the solution is expressed as: Class members declared as friend can be accessed by only those classes explicitly listed as being collaborators. > - I would extend the syntax to namespaces. For examples, '\MyNS\' (syntax > to dicuss) would declare every class in the '\MyNS' namespaces or > sub-namespaces as friends. Must support 'friend __NAMESPACE__' or something > equivalent. This, coupled with a protected __construct() method would > provide something quite similar to package-private access, but more > extensible and powerful. > > > > François, would you be willing to describe more of the reasoning > behind this? Specifically "more extensible and powerful" [for what?]. > Also, I can't think of a better way to word that request, but see how > it can come across as a direct-challenge. Just want to say I'm > genuinely curious to what the intended outcome is and don't mean to > come across as "point-y". > One example comes to mind. Imagine you have a service "manager" class that accepts an abstract "worker" class. You then have several concrete worker implementations. It would be nice to be able to, at a namespace level, say all these workers are friends of the manager. Systems where you have pluggable drivers (eg databases) or lots of collaborating objects (charting systems) would benefit from a granular way to declare friendship. > I don't know that I would use friendship > as a means to make an entire package (namespace, in PHP's case) aware > of a single object. I think it's the other way around: a single object declares its friendship with an entire namespace. Looking forward to the RFC!
