在golang中的类型中添加到匿名切片

Question

I want to add a few helper methods attached onto a slice. So I created a type which is of []*MyType Is there any way to add to that slice of MyTypes? append will not recognise the slice.

package main

import "fmt"


type MyType struct{
    Name string
    Something string
}


type MyTypes []*MyType 

func NewMyTypes(myTypes ...*MyType)*MyTypes{
    var s MyTypes = myTypes
    return &s
}

//example of a method I want to be able to add to a slice
func(m MyTypes) Key() string{
    var result string

    for _,i := range m{
        result += i.Name + ":" 
    }

    return result
}


func main() {
    mytype1 ,mytype2 := MyType{Name:"Joe", Something: "Foo"},  MyType{Name:"PeggySue", Something: "Bar"}

    myTypes:= NewMyTypes(&mytype1,&mytype2) 

    //cant use it as a slice sadface
    //myTypes = append(myTypes,&MyType{Name:"Random", Something: "asdhf"})

    fmt.Println(myTypes.Key())
}

I don't want to wrap it in another type and name the param even though I'm sorta doing it.. Because of json marshalling will probably be different

What would be the way to add to the MyTypes slice?

I really want to just be able to add a method to a slice so it can implement a specific interface and not effect the marshalling.. Is there a different better way?

Thanks

Answer 1

Update: This answer once contained two ways to solve the problem: my somewhat clunky way, the DaveC's more elegant way. Here's his more elegant way:

package main

import (
    "fmt"
    "strings"
)

type MyType struct {
    Name      string
    Something string
}

type MyTypes []*MyType

func NewMyTypes(myTypes ...*MyType) MyTypes {
    return myTypes
}

//example of a method I want to be able to add to a slice
func (m MyTypes) Names() []string {
    names := make([]string, 0, len(m))
    for _, v := range m {
        names = append(names, v.Name)
    }
    return names
}

func main() {
    mytype1, mytype2 := MyType{Name: "Joe", Something: "Foo"}, MyType{Name: "PeggySue", Something: "Bar"}
    myTypes := NewMyTypes(&mytype1, &mytype2)
    myTypes = append(myTypes, &MyType{Name: "Random", Something: "asdhf"})
    fmt.Println(strings.Join(myTypes.Names(), ":"))
}

Playground: https://play.golang.org/p/FxsUo1vu6L