Generics - I Wish You Were Here...

August 19, 2017   

This is an experience report about how generics in go could have helped us in one of our use case. There is a lot that can be/has been said about generics is go. I am going to keep this post short and simple and going to document a use case where I think generics in go might have been useful for us.

I like how easy it is to build command line applications in go, We have a common framework for building command line apps. Different command line applications need to have different configuration, that are passed to common framework. This is where the need for generics pop up, as you can see Configuration type(in code below) is an interface{} and we need to do Type Assertion such as cfg := configuration.(*appConfig), to get the application configuration.

type (
	//Configuration is a marker interface to use because we don't have generics
	//It is used when passing a configuration object around
	Configuration interface{}

	//Application is a struct that holds the definition of the application to run
	Application struct {
		Name          string
		Description   string
		Version       string
		Options       []cli.Flag
		Subcommands   []cli.Command
		Configuration Configuration

If go had generics, we could have a generic type instead of an interface{} for the Configuration type.