Backup source of Example Programs(No. 7)

[[Documentation]]

*Examples

**List Concatenation

 append(c(1,c(2,c(3,n))),c(4,c(5,n)),result).
 append(X,Y,Z), n(X)      :- Y=Z.
 append(X,Y,Z), c(A,X1,X) :- c(A,Z1,Z), append(X1,Y,Z1).

RESULT: result(c(1,c(2,c(3,c(4,c(5,n)))))) with the two rules above.

The first line of the above example is written using the ''term abbreviation scheme'' explained in the [[Syntax]] page.  By making more use of the 
term abbreviation scheme and the Prolog-like list syntax, list concatenation
can be written also as:

 result = append([1,2,3],[4,5]).
 Z=append([],    Y) :- Z=Y.
 Z=append([A|X1],Y) :- Z=[A|append(X1,Y)].

RESULT: result=[1,2,3,4,5] with the two rules above.

**Self-Organizing Loops
 a(free,free),a(free,free),a(free,free),a(free,free),a(free,free),
 a(free,free),a(free,free),a(free,free),a(free,free),a(free,free),
 a(free,free),a(free,free),a(free,free),a(free,free),a(free,free),
 a(free,free),a(free,free),a(free,free),a(free,free),a(free,free),
 a(free,free),a(free,free),a(free,free),a(free,free).
    a(X,free),a(free,Y) :- a(X,C),a(C,Y).

RESULT: Many possible results.  You can obtain them by running the program using the ''-s'' option.

**Vending Machine
 {customer,a,five,one,one,hunger,hunger}.  % Customer a has $7, buying 2 chocos
 {customer,b,five,hunger}.                 % Customer b has $5, buying 1 choco
 {vending,choco,choco,choco,one,one}.      % Vending machine has 3 chocos
    {customer,$c,hunger,five},  {vending,$v,choco,one,one}
 :- {customer,$c,choco,one,one},{vending,$v,five}.
    {customer,$c,hunger,one,one,one},{vending,$v,choco}
 :- {customer,$c,choco},             {vending,$v,one,one,one}.

Two customers with different amounts of coins and hunger
are buying some chocolates from a vending machine.
Each chocolate costs three
and only two kinds of coins are considered: one and five.

Run this program several times in shuffle mode (type shuffle)
to observe its non-deterministic behavior.

 RESULT 1:
  {customer,a,choco,choco,one},
  {customer,b,choco,one,one},
  {vending,five,five,one}, <RULES>
 RESULT 2:
  {customer,a,hunger,hunger,five,one,one},
  {customer,b,choco,one,one}, 
  {vending,choco,choco,five}, <RULES>

Observe that applying each rule preserves
the total amount of coins and chocos within this system.
Backup source of Example Programs (No. 7)
