Collection library
From wiki.visual-prolog.com
A collection is a value that contains a number (i.e. from zero to infinite) of other values.
Lists, sets, dictionaries, arrays, hash tables, etc are all collections.
A collection can also contain one value, but data types that by nature always contains exactly one value is not a collection. So a list with one element is a collection, but a variable which also contains one element is not a collection.
Collections can be persistent or modifiable:
- Persistent
- A persistent collection never changes members. Meaning that when you insert or remove a member from persistent collection, you will receive a new collection and the old one will stay unchanged.
- Modifiable
- Members can be added to and removed from a modifiable collection. Meaning that when you insert or remove a member from a modifiable collection, the old value of the collection is lost only the one exists. I.e. modifiable collections are updated destructively.