You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
package main
|
|
|
|
// these are sentinel errors. Look at article in pointers_errors dictory README.md
|
|
// var (
|
|
// ErrNotFound = errors.New("could not find word you were looking for")
|
|
// ErrWordExists = errors.New("key already exists, Add failed")
|
|
// )
|
|
|
|
// Instead we implement our own type that implements the error interface
|
|
// This has more benefits because you can do type checks instead of comparing error strings
|
|
// or sentinel errors. See the article https://dave.cheney.net/2016/04/07/constant-errors
|
|
const (
|
|
ErrNotFound = DictionaryErr("could not find word you were looking for")
|
|
ErrWordExists = DictionaryErr("key already exists, Add failed")
|
|
ErrWordDoesNotExist = DictionaryErr("key already exists, Add failed")
|
|
)
|
|
|
|
type DictionaryErr string
|
|
|
|
func (e DictionaryErr) Error() string {
|
|
return string(e)
|
|
}
|
|
|
|
type Dictionary map[string]string
|
|
|
|
func (d Dictionary) Search(word string) (string, error) {
|
|
val, ok := d[word]
|
|
if !ok {
|
|
return val, ErrNotFound
|
|
}
|
|
|
|
return val, nil
|
|
}
|
|
|
|
// Ok...this works because a map value is a pointer to a runtime.hmap structure
|
|
// So when you pass the map reference to this function it's actually copying the
|
|
// pointer so no need to &d get mem pointer.
|
|
func (d Dictionary) Add(word, definition string) error {
|
|
_, ok := d[word]
|
|
if ok {
|
|
return ErrWordExists
|
|
}
|
|
|
|
d[word] = definition
|
|
return nil
|
|
|
|
// The authors alt implementation
|
|
// _, err := d.Search(word)
|
|
|
|
// switch err {
|
|
// case ErrNotFound:
|
|
// d[word] = definition
|
|
// case nil:
|
|
// return ErrWordExists
|
|
// default:
|
|
// return err
|
|
// }
|
|
|
|
// return nil
|
|
}
|
|
|
|
func (d Dictionary) Update(word, definition string) error {
|
|
_, ok := d[word]
|
|
if !ok {
|
|
return ErrWordDoesNotExist
|
|
}
|
|
d[word] = definition
|
|
return nil
|
|
}
|
|
|
|
func (d Dictionary) Delete(word string) {
|
|
//Go has a built-in function delete that works on maps. It takes two arguments. The first is the map and the second is the key to be removed.
|
|
delete(d, word)
|
|
}
|