Prevent receiver methods for custom (alias) types to be called by value?-CodePudding

I have defined a custom (alias) type type Dict map[interface{}]interface{} with a couple of receiver methods getValue(key interface{}) (interface{}, bool) and getValue(key interface{}) (interface{}, bool).

I'm suspecting that these methods are called by value, i.e. the Dict is copied by value to the function as the receiver d.

If I change the receiver to (d *Dict), then I need to index using (*d)[key], which is very cumbersome.

How can I check whether Dict is copied by value and change it to copy by reference for efficiency?

package main

import (
    "fmt"
)

type Dict map[interface{}]interface{}

func (d Dict) getValue(key interface{}) (interface{}, bool) {
    value, found := d[key]
    return value, found
}

func (d Dict) setValue(key, value interface{}) {
    d[key] = value
}

func main() {
    dict := Dict{"foo": "bar", 1: []int{1, 2, 3}}
    value, found := dict.getValue(1)
    if found {
        fmt.Println("value:", value)
    }
}

CodePudding user response：

everything in Go is pass by value.

CodePudding user response：

A map is essentially a struct that has a pointer to where the values are stored.

In a way what you are doing is already implicitly passing a reference of the map down to your methods.

So, no need to do anything else. It's fine as it is.