Mastering Python Design Patterns - Second Edition

Real-world examples

The memento pattern can be seen in many situations in real life.

An example could be found in the dictionary we use for a language, such as English or French. The dictionary is regularly updated through the work of the academic experts, with new words being added and other words becoming obsolete. Spoken and written languages evolve and the official dictionary has to reflect that. From time to time, we revisit a previous edition to get an understanding of how the language was used at some point in the past. This could also be needed simply because information can be lost after a long period of time, and to find it, you may need to look into old editions. That can be useful to understand something in a particular field. ...