使用golang中相同结构的func引用另一个字段

Question

I have a struct looks something like this:

type Job struct {
    Action  func()
    Cron    string
}

So for an instance of this struct, is it possible for the code inside the implementation of Action to get a reference to Cron? Thanks.

Answer 1

Use a closure to create the Action function:

func MakeAction(job *Job) func() {
    return func() {
        // function that uses the variable job
    }
}

You can use the MakeAction function like this:

j := &Job{ nil, "foo" }
j.Action = MakeAction(j)

Notice that this will behave in possibly unexpected ways when somebody makes a copy of the Job structure—the reference inside the closure created by MakeAction() will still point to the original instance (instead of the copy).