====== Animals kb ======
{{tag>knowledge_base}}
===== Description =====
A simple knowledge base for identifying animals.


**Source**:  PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7.

===== Download =====
Program source code: {{animals_kb.pl}}
===== Listing =====
<code prolog>
% Figure 16.1  A simple knowledge base for identifying animals.

% Adapted from Winston (1984). The relation 'askable' defines those things

% that can be asked by user. The operators '::', if, then, 'and', 'or'

% are declared as in Figure 16.6.





%     A small knowledge base for identifying animals



:-  op( 100, xfx, [ has, gives, 'does not', eats, lays, isa]).



:-  op( 100, xf, [ swims, flies]).

:-  op( 200, xfy, [:, ::]).

:-  op( 185, fx, if).

:-  op( 190, xfx, then).

:-  op( 180, xfy, or).

:-  op( 160, xfy, and).





rule1 ::   if

		Animal has hair

	   or

		Animal gives milk

	then

		Animal isa mammal.





rule2 ::   if

		Animal has feathers

	   or

		Animal flies  and

		Animal lays eggs

	then

		Animal isa bird.



rule3 ::  if

		Animal isa mammal  and

              ( Animal eats meat

                  or

		Animal has 'pointed teeth' and

		Animal has claws  and

		Animal has 'forward pointing eyes' )

	then

		Animal isa carnivore.



rule4 ::  if

		Animal isa carnivore  and

		Animal has 'tawny color'  and

		Animal has 'dark spots'

        then

		Animal isa cheetah.



rule5 ::  if

		Animal isa carnivore  and

		Animal has 'tawny color'  and

		Animal has 'black stripes'

	then

		Animal isa tiger.



rule6 ::  if

		Animal isa bird  and

		Animal 'does not' fly  and

		Animal swims

	then

		Animal isa penguin.



rule7 :: if

		Animal isa bird  and

		Animal isa 'good flyer'

	then

		Animal isa albatross.





fact :: X isa animal   :-

  member( X, [cheetah, tiger, penguin, albatross]).





askable( _ gives _, 'Animal' gives 'What').



askable( _ flies, 'Animal' flies).



askable( _ lays eggs, 'Animal' lays eggs).



askable( _ eats _, 'Animal' eats 'What').



askable( _ has _, 'Animal' has 'Something').



askable( _ 'does not' _, 'Animal' 'does not' fly).



askable( _ swims, 'Animal' swims).



askable( _ isa 'good flyer', 'Animal' isa 'good flyer').



</code>
===== Comments =====