Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 16 Interfaces 199 16.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not. Every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 16 Interfaces 199 16.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not. Every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 16 Interfaces 199 16.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not. Every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 15 Interfaces 189 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not. Every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 15 Interfaces 189 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not. Every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 15 Interfaces 187 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not: every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 15 Interfaces 187 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not: every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 15 Interfaces 188 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not: every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 15 Interfaces 187 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not: every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies

Promotion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 15 Interfaces 187 15.1 Iteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dynamic languages as being "typeless", they are definitely not: every object, whether primitive or user-defined, has a type. The lack of type declarations in most dynamic lan- guages, however, means that object-oriented dispatch. Operators are just functions with special notation – to extend addition to new user-defined data types, you define new methods for the + function. Existing code then seamlessly applies