Smalltalk provides a very high degree of abstractions and encapsulations. Everything is an object with specific characteristics and behaviors. Objects use messages to communicate to each other. The only thing that an object knows about another object is the other object' s interface. Private data members and methods are hidden.
Objects can inherit the characteristics and behaviors from parent objects.
This violates the principles of information hiding and may lead to unintended side-effects. Pascal is an example of a block structured procedural language. Pascal is widely used for teaching purposes since it was designed specifically that way. By the 1980s, it was widely used in businesses and industries. But, since mid 1990s until today, the usage of Pascal has decreased in popularity in those areas.