The ACM Computing Classification System (1998)

D.3.3 Language Constructs and Features

• Abstract data types
• Classes and objects 
• Concurrent programming structures
• Constraints 
• Control structures
• Coroutines
• Data types and structures
• Dynamic storage management
• Frameworks 
• Inheritance 
• Input/output
• Modules, packages
• Patterns 
• Polymorphism 
• Procedures, functions, and subroutines
• Recursion