dict

An ISO Prolog dictionary, implemented as an incomplete binary search tree.

Inspired by Chapter 15.3 from The Art of Prolog by Sterling and Shapiro.

Tested with Scryer Prolog.

Exports

• add(+Key, ?Dict, ?Value) - adds a key-value pair to the dictionary, if it doesn't already exist.
• balance(+Dict, -Dict) - balances a dictionary.
• get(+Key, +Dict, -Value) - gets the value associated with the key. Fails if key does not exist.
• height(+Key, -Height) - calculates and returns the height of the dictionary's tree.
• put(+Key, ?Dict, -Dict1, +Value) - adds/updates the value of a key, returning a new dictionary.
• to_list(+Dict, -List) - serializes a dictionary to a list of key-value pairs.

Testing

$ scryer-prolog -f test/dict.pl
Running test "add/get"
Running test "put"
Running test "to_list"
Running test "height/balance"

See Also

Many prologs ship with a balanced tree dictionary implementation called assoc.