How to update slice inside map - go

Question

I'm struggling with updating a slice inside map rulesByCountry without any success.
The value of enabled changes only inside the function UpdateName but the map itself still sees this value unchanged. I assume it's something to do with pointers. I guess I did not grasp the concept of it. Can someone direct me what I'm doing wrong here? I tried a lot of things and run out of options. I would appreciate any kind of help.
import (
"fmt"
)
// Consts
const RuleSeparateStreetNameFromHome string = "Separate street number from home"
// Types
type Address struct {
AddressLines []string
Country string
}
type RuleChain []RuleDefinition
type RuleDefinition struct {
Name string
Enabled bool
}
//Map
var rulesByCountry map[string][]RuleDefinition = map[string][]RuleDefinition{
"DE": {
{
Name: RuleSeparateStreetNameFromHome,
// TODO some logic,
Enabled: false,
},
},
}
func main() {
var addr *Address
addr = &Address{
AddressLines: []string{
"Street3",
},
Country: "DE",
}
rules := GetRulesForCountry(addr.GetCountry())
rules.UpdateName(RuleSeparateStreetNameFromHome)
fmt.Println(rules)
}
func GetRulesForCountry(country string) RuleChain {
if rules, ok := rulesByCountry[country]; ok {
return rules
}
return nil
}
func (a *Address) GetFirstAddressLine() string {
return a.GetAddressLine(1)
}
func (a *Address) GetAddressLine(lineNumber int) string {
if lineNumber <= 0 {
return ""
}
lines := a.GetAddressLines()
if len(lines) >= lineNumber {
return lines[lineNumber-1]
}
return ""
}
func (m *Address) GetAddressLines() []string {
if m != nil {
return m.AddressLines
}
return nil
}
func (r *RuleChain) UpdateName(name string) {
for _, rule := range *r {
if rule.Name == name {
rule.Enabled = true
fmt.Print(rule)
}
}
}
func (m *Address) GetCountry() string {
if m != nil {
return m.Country
}
return ""
}

Answer 1

Based on the inputs of mkopriva
package main
import (
"fmt"
)
// Consts
const RuleSeparateStreetNameFromHome string = "Separate street number from home"
// Types
type Address struct {
AddressLines []string
Country string
}
type RuleChain []*RuleDefinition
type RuleDefinition struct {
Name string
Enabled bool
}
//Map
var rulesByCountry map[string][]*RuleDefinition = map[string][]*RuleDefinition{
"DE": {
{
Name: RuleSeparateStreetNameFromHome,
// TODO some logic,
Enabled: false,
},
},
}
func main() {
var addr *Address
addr = &Address{
AddressLines: []string{
"Street3",
},
Country: "DE",
}
rules := GetRulesForCountry(addr.GetCountry())
rules.UpdateName(RuleSeparateStreetNameFromHome)
fmt.Println(rules[0])
}
func GetRulesForCountry(country string) RuleChain {
if rules, ok := rulesByCountry[country]; ok {
return rules
}
return nil
}
func (a *Address) GetFirstAddressLine() string {
return a.GetAddressLine(1)
}
func (a *Address) GetAddressLine(lineNumber int) string {
if lineNumber <= 0 {
return ""
}
lines := a.GetAddressLines()
if len(lines) >= lineNumber {
return lines[lineNumber-1]
}
return ""
}
func (m *Address) GetAddressLines() []string {
if m != nil {
return m.AddressLines
}
return nil
}
func (r *RuleChain) UpdateName(name string) {
for _, rule := range *r {
if rule.Name == name {
rule.Enabled = true
fmt.Print(rule)
}
}
}
func (m *Address) GetCountry() string {
if m != nil {
return m.Country
}
return ""
}
Output:
&{Separate street number from home true}&{Separate street number from home true}