%Prolog example developed by Dr. Klerer, CSUSB
test :- exp([a,s,i,n],_,0).
t(X) :- exp(X,_,0).

exp(X) :- size(X,Y), exp(X,Y,0).

exp(Text,Size,0) :- v(Text,Size).
exp(Text,Size,Count) :- S is Size-Count, v(T1,S), 
	 append(T1,T2,Text), exp(T2,Count,0).
exp(Text,Size,Count) :- C is Count+1, C < Size, exp(Text,Size,C).

e1(X,L) :- size(X,Y), exp1(X,Y,0,L).

exp1(Text,Size,0,Text) :- v(Text,Size), !.
exp1(Text,Size,Count,[T1,L]) :- S is Size-Count, v(T1,S), 
	 append(T1,T2,Text), exp1(T2,Count,0,L), !.
exp1(Text,Size,Count,L) :- C is Count+1, C < Size, exp1(Text,Size,C,L).


e(X,L) :- size(X,Y), e(X,Y,L).
e(Text,Size,Text) :- v(Text,Size).
e(Text,Size,[T1,L]) :-append(T1,T2,Text), v(T1,Size), e(T2,L).
e(Text,Size,L) :-  S is Size-1, S > 0, e(Text,S,L).


append([],L,L).
append([X; L1],L2,[X; L3]) :- append(L1,L2,L3).

v(Word,Size) :- w(Word), size(Word,Size).

ex(T) :- va(T), !.
ex(T) :- va(T1), ex(T2), append(T1,T2,T).

ex(T,T) :- va(T).
ex(T,[T1; L]) :-  append(T1,T2,T), va(T1), ex(T2,L).


va(Word) :- va(Word,10).
va(W,C) :- v(W,C).
va(W,C) :- C1 is C-1, C1 > 0, va(W,C1). 

size([],0).
size([X; Y],Z) :- size(Y,Q), Z is Q+1.
 
w([a]).
w([s,i,n]).
w([x]).
w([y]).
w([x,y]).

:- write('Loaded'), nl.