RosettaCodeData/Task/Anagrams/Prolog/anagrams.pro
2020-02-17 23:21:07 -08:00

49 lines
1.4 KiB
Prolog

:- use_module(library( http/http_open )).
anagrams:-
% we read the URL of the words
http_open('http://wiki.puzzlers.org/pub/wordlists/unixdict.txt', In, []),
read_file(In, [], Out),
close(In),
% we get a list of pairs key-value where key = a-word value = <list-of-its-codes>
% this list must be sorted
msort(Out, MOut),
% in order to gather values with the same keys
group_pairs_by_key(MOut, GPL),
% we sorted this list in decreasing order of the length of values
predsort(my_compare, GPL, GPLSort),
% we extract the first 6 items
GPLSort = [_H1-T1, _H2-T2, _H3-T3, _H4-T4, _H5-T5, _H6-T6 | _],
% Tnn are lists of codes (97 for 'a'), we create the strings
maplist(maplist(atom_codes), L, [T1, T2, T3, T4, T5, T6] ),
maplist(writeln, L).
read_file(In, L, L1) :-
read_line_to_codes(In, W),
( W == end_of_file ->
% the file is read
L1 = L
;
% we sort the list of codes of the line
msort(W, W1),
% to create the key in alphabetic order
atom_codes(A, W1),
% and we have the pair Key-Value in the result list
read_file(In, [A-W | L], L1)).
% predicate for sorting list of pairs Key-Values
% if the lentgh of values is the same
% we sort the keys in alhabetic order
my_compare(R, K1-V1, K2-V2) :-
length(V1, L1),
length(V2, L2),
( L1 < L2 -> R = >; L1 > L2 -> R = <; compare(R, K1, K2)).