extending interfaces

[jryannel]

The idea is to allow interfaces to extend other interfaces.

E.g.

interface A {}
interface B extends A {}

in YAML this would be

interfaces:
  - name: B
    extends: A

For C++ we would extend one interface with another:

class B extends A {};

[jryannel]

Now you can extend interface using the extends keyword:

• We don't allow multi extends, only single extends

IDL

interface Common {
}

interface Counter extends Common {
}

or using an external type:

import demo

interface Counter extends demo.Common {
}

YAML

name: demo.bbb
version: "1.0"

imports: 
  - name: demo.aaa

interfaces:
  - name: Common
  - name: Counter
    extends:
      name: Common
      import: demo.aaa

Template

In the go template we can then access the extends information:

• TODO: Make the extends simpler in go (how does it look in C++/Rust?)

  {{- range .Module.Interfaces }}
  {{- $class := .Name }}
  type {{$class}} interface {
  {{- if .HasExtends }}
  {{- if .Extends.Import }}
  {{camel (splitLast .Extends.Import ".")}}.{{Camel .Extends.Name }}
  {{- else }}
  {{Camel .Extends.Name }}
  {{- end }}
  {{- end }}
  }
  {{- end }}