%*****************************************************************************
%Anagrams and Backtracking
%
%*****************************************************************************
:- ensure_loaded('listprocessing').
:- ensure_loaded('utilities').

%=====================
% Word Database
%===================== 
word(nook).
word(look).
word(invent).
word(code).
word(logic).
word(bedtime).
word(runtime).
word(run).
word(like).
word(destroy).
word(geek).
word(software).
word(prolog).
word(artificial).
word(nonmonotonic).
aFavorite(logic).
aFavorite(geek).

%-------------------------------------------------------------------------------------
% BackTracking and the Cut.
%-------------------------------------------------------------------------------------
bting() :-  
      word(X),
      aFavorite(X), nl, writenl(X),  
      !,
      word(Y), writeseqnl([Y,' ']), fail.


%-------------------------------------------------------------------------------------
% Generate and Test
% 
%-------------------------------------------------------------------------------------
anagram(Problem,Solution) :-
   atom_chars(Problem,ProblemLetters),
   perm(ProblemLetters,Attempt),
   atom_chars(Solution,Attempt),
   word(Solution),!.


%-------------------------------------------------------------------------------------
%   If word is more than a few letters number of permutations
%   is more than number of words in the dictionary. 
%   So to Prune Search Start with known words  then just
%   check if known word " is a permutation" of problem word.
%
%   Compare the execution times of the two versions on a long word.
%-------------------------------------------------------------------------------------
anagram1(Problem,Solution) :-
   atom_chars(Problem,ProblemLetters),
   word(Solution),
   atom_chars(Solution,SolutionLetters),
   isPerm(ProblemLetters,SolutionLetters),!.