Simple Go object with functional programming

package person

type Name string

type Age int

type Person struct {
    name Name
    age  Age
}

func NewPerson(name Name, age Age) *Person {
    return &Person{
        name: name,
        age:  age,
    }
}

func GetName(p *Person) Name {
    return p.name
}

func SetName(p *Person, name Name) *Person {
    return &Person{
        name: name,
        age:  p.age,
    }
}

func GetAge(p *Person) Age {
    return p.age
}

func SetAge(p *Person, age Age) (*Person, error) {
    if age < 0 {
        return nil, fmt.Errorf("age cannot be negative: %d", age)
    }
    return &Person{
        name: p.name,
        age:  age,
    }, nil
}


//___________________________________________________________________________________________________

package main

import (
    "fmt"
    "person"
)

func main() {
    p := person.NewPerson("Alice", 30)

    // Get the person's name using the GetName function
    name := person.GetName(p)
    fmt.Printf("Name: %s\n", name)

    // Set the person's name using the SetName function
    p = person.SetName(p, "Bob")
    name = person.GetName(p)
    fmt.Printf("Name: %s\n", name)

    // Get the person's age using the GetAge function
    age := person.GetAge(p)
    fmt.Printf("Age: %d\n", age)

    // Set the person's age using the SetAge function
    var err error
    p, err = person.SetAge(p, 40)
    if err != nil {
        panic(err)
    }
    age = person.GetAge(p)
    fmt.Printf("Age: %d\n", age)
}