Allow code generation for primitive types

[rickb777]

It would be nice to have an easy way to generate collections of strings, ints etc.

Even though there is only a small set of Go primitive types, generating the collections for them using gen would be a bit better than hand-coding because future developments of gen could be made use of with very little effort (just run gen again).

[clipperhouse]

Thanks, I’ve been thinking about this. This wouldn’t actually require codegen, it could just be an import, since it’s a finite set of known types. I’ll get to it after I’ve gotten the projection bits stable.

[clipperhouse]

@rickb777 The recent changes implement this, so long as it’s your type, along the lines of type MyType int.

Doing this in a general sense for all primitives would still require the creation of some sort of alias type, like type Ints []int.

For purposes of gen, I’m happy with the current approach but feel free to tell me about what you’d like a more general solution to look like, maybe it’s an idea for separate project.