将清单解组

Question

Moved from python to golang:

jsonBlob := `{ "test" : {"thing":["team1", "team2"]}}`

type other map[string]Myset
type stuff map[string]other
type MySet struct {
    set mapset.Set
}

//Custom unmarshaller
func (s *MySet) UnmarshalJSON(p []byte) error {
    var a []interface{}
    if err := json.Unmarshal(p, &a); err != nil {
        return err
    }
    s.set = mapset.NewSet(a)
    return nil
}

 // Unmarshall it
 var s stuff
 err := json.Unmarshall(jsonBlob, &s)
 if err != nil {
  return err   
}

but it throws: runtime error: hash of unhashable type []interface {}

Answer 1

Given that the data type you wish to use is an interface, and does not satisfy the json.Unmarshaler interface, you have two options:

1. Unmarshal to an array, then convert to your preferred type.

2. Create a custom type, that wraps your preferred type, and provides an UnmarshalJSON method. This is functionally the same as #1, but may be easier to use. Example:

   type MySet struct {
       set mapset.Set
   }
   
   func (s *MySet) UnmarshalJSON(p []byte) error {
       var a []interface{}
       if err := json.Unmarshal(p, &a); err != nil {
           return err
       }
       s.set = mapset.NewSet(a)
       return nil
   }
   

   (Note, this code is untested; it is not meant to be a complete solution, but a guide in the right direction.)