SWI-Prolog -- select

Documentation
- Reference manual
  - SWI-Prolog extensions
    - Dicts: structures with named arguments
      - Predicates for managing dicts
        
        is_dict/1
        
        is_dict/2
        
        get_dict/3
        
        get_dict/5
        
        dict_create/3
        
        dict_pairs/3
        
        put_dict/3
        
        put_dict/4
        
        del_dict/4
        
        :</2
        
        select_dict/3
        
        >:</2
        
        Destructive assignment in dicts
- Packages

Availability:built-in

[semidet]select_dict(+Select, +From, -Rest)

True when the tags of Select and From have been unified, all keys in Select appear in From and the corresponding values have been unified. The key-value pairs of From that do not appear in Select are used to form an anonymous dict, which us unified with Rest. For example:

?- select_dict(P{x:0, y:Y}, point{x:0, y:1, z:2}, R).
P = point,
Y = 1,
R = _G1705{z:2}.

See also :</2 to ignore Rest and >:</2 for a symmetric partial unification of two dicts.