71 lines
1.4 KiB
Go
71 lines
1.4 KiB
Go
// For more tutorials: https://blog.learngoprogramming.com
|
|
//
|
|
// Copyright © 2018 Inanc Gumus
|
|
// Learn Go Programming Course
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
|
//
|
|
|
|
package main
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"reflect"
|
|
"strings"
|
|
)
|
|
|
|
type item interface {
|
|
discount(float64)
|
|
fmt.Stringer
|
|
}
|
|
|
|
// schema adds an additional category field
|
|
// to the product types.
|
|
type schema struct {
|
|
// Category is the product category field.
|
|
Category string
|
|
|
|
// Item is an interface value.
|
|
// Here, we are embedding an interface value.
|
|
Item item
|
|
}
|
|
|
|
type list []item
|
|
|
|
// MarshalJSON is an implementation of the json.Marshaler interface.
|
|
// json.Marshal and Decode call this method.
|
|
func (l list) MarshalJSON() ([]byte, error) {
|
|
var schemas []schema
|
|
|
|
for _, it := range l {
|
|
// TypeOf -> finds the dynamic type of "it"
|
|
// Elem -> returns the element type of the pointer
|
|
// Name -> returns the type name as string
|
|
cat := reflect.TypeOf(it).Elem().Name()
|
|
schemas = append(schemas, schema{cat, it})
|
|
}
|
|
|
|
return json.Marshal(schemas)
|
|
}
|
|
|
|
func (l list) String() string {
|
|
if len(l) == 0 {
|
|
return "Sorry. We're waiting for delivery 🚚."
|
|
}
|
|
|
|
var str strings.Builder
|
|
|
|
for _, it := range l {
|
|
str.WriteString(it.String())
|
|
str.WriteRune('\n')
|
|
}
|
|
|
|
return str.String()
|
|
}
|
|
|
|
func (l list) discount(ratio float64) {
|
|
for _, it := range l {
|
|
it.discount(ratio)
|
|
}
|
|
}
|