Embeding a struct (just writing the type) creates a “has a relationship” with the parent. If the child implements any interface parent can directly invoke those methods. If there are more than one embedding and they implement a common method it’s okay as long as we don’t attempt to directly invoke it on parent (trying to do so results in compilation error - ambiguous selector) While encoding json (marshalling), encoder internally checks if the type implements json.

1. Overview Json is, in many places, the preferred way of storing data due to it’s brevity (mostly compared to xml) and human readability. While working in any web framework which involve operation with data models and templates, usage of json data format is almost inevitable. Languages like Python, Ruby even have this format conceptually built into the core language library itself. Hash in ruby and dictionaries in python which allow json-(dictionary/hash) conversion with an ease.