nx::Class create Eatable +nx::Class create Fish -superclass Eatable { + :property name +}
package req nx
Define the two classes Eatable and Fish. Eatable is a class
for all eatable things, a Fish is a subclass ant therefore
eatable.
nx::Class create Eatable +nx::Class create Fish -superclass Eatable { + :property name +}
A FoodBax may only contain eatable items. Therefore with we define
items as a property of type Eatable" which has a multiplicity of
+0..n (might contain 0 to n eatable items). Furthermore, we define
items as incremental, such we can add / remove items with item
add or item remove.
nx::Class create FoodBox { + :property -incremental item:object,type=::Eatable + :public method print {} { + set string "Foodbox contains:\n" + foreach i ${:item} {append string " [$i cget -name]\n"} + return $string + } +}
Create two fishes, Wanda and Nemo:
% set f1 [Fish new -name "Wanda"] +% set f2 [Fish new -name "Nemo"]
Create a Foodbox and add the two fishes:
% set fb [FoodBox new] +% $fb item add $f1 +% $fb item add $f2
Return the print string of the contents:
% $fb print
+Foodbox contains:
+ Nemo
+ Wanda