What defines how a programming language classifies values and expressions?

The definition of how a programming language classifies values and expressions is fundamentally tied to its type system. An object-based type system is a model in which types are assigned to values based on their object characteristics and the support of object-oriented programming paradigms. This approach allows for defining types in terms of objects and their behaviors, which is essential in languages that heavily utilize objects for structuring data.

In an object-based type system, classes serve as blueprints for creating objects, and the type system can understand and enforce rules about what types of values can be associated with various operations based on their class definitions. This classification is vital for maintaining integrity within the programming environment and ensuring that operations are valid for the types being used.

Other types of typing strategies, such as dynamic and static typing, focus on when type checking occurs (runtime vs. compile time) and how type information is handled but do not specifically define how classes of values and expressions are organized according to an object-oriented structure. Type inference relates to the ability of the compiler to automatically deduce types but again does not focus on the classification aspect itself. Thus, an object-based type system best captures the essence of how values and expressions are categorized in programming languages that utilize this paradigm.