% file: 01-dictionary.p
%       defines vocabulary
%       adds entry listing for singular and plural

% dictionary(Word, Type, Listing).

dictionary(bluebird,noun,[[singular, bluebird], [plural, bluebirds]]).
dictionary(woodduck,noun,[[singular, woodduck], [plural, woodducks]]).
dictionary(woodpecker,noun,[[singular, woodpecker], [plural, woodpeckers]]).
dictionary(anemone,noun,[[singular, anemone], [plural, anemones]]).
dictionary(lily,noun,[[singular, lily], [plural, lilies]]).

% in_dictionary(Word,Entry) :: Word is in dictionary under entry Entry

in_dictionary(Word,Word) :-
   dictionary(Word,_,_).

in_dictionary(Word,Entry) :-
   singular_of(_,Word,Entry).

in_dictionary(Word,Entry) :-
   plural_of(_,Word,Entry).

% singular_of(Word,Singular,Entry) :: Word has singular Singular under
%                                              entry Entry
singular_of(Word,Singular,Word) :-
   dictionary(Word,_,Listing),
   extract(singular,Listing,Singular), !.

singular_of(Word,Singular,Entry) :-
   dictionary(Entry,_,Listing),
   in_listing(Word,Listing),
   extract(singular,Listing,Singular), !.

% plural_of(Word,Plural,Entry) :: Word has plural Plural under
%                                          entry Entry
plural_of(Word,Plural,Word) :-
   dictionary(Word,_,Listing),
   extract(plural,Listing,Plural), !.

plural_of(Word,Plural,Entry) :-
   dictionary(Entry,_,Listing),
   in_listing(Word,Listing),
   extract(plural,Listing,Plural), !.

in_listing(Word,[[_Usage, Word] | _Rest]).
in_listing(Word,[_ | Rest]) :- in_listing(Word,Rest).

extract(Attribute,[[Attribute, Value] | _Rest], Value).
extract(Attribute,[_ | Rest], Value) :- extract(Attribute,Rest,Value).