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You can introduce a Food class and
define the Vegetable, Dairy, Meat, and Grain
classes to be subclasses of the Food class.
Note that the fCalories, cCalories, and pCalories
instance variables appear in the Food class definition alone, but
the effect is equivalent to placing those variables in all the subclass
definitions as well. The four subclasses are said to inherit
instance variables from the Food class:
Food class definition Object subclass: #Food instanceVariableNames: 'fCalories cCalories pCalories' classVariableNames: '' poolDictionaries: '' Vegetable class definition Food subclass: #Vegetable instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' Dairy class definition Food subclass: #Dairy instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' Meat class definition Food subclass: #Meat instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' Grain class definition Food subclass: #Grain instanceVariableNames: '' classVariableNames: '' poolDictionaries: ''