computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...

, having value semantics (also value-type semantics or copy-by-value semantics) means for an object that only its value counts, not its identity.

Immutable In object-oriented and functional programming, an immutable object (unchangeable object) is an object whose state cannot be modified after it is created.Goetz et al. ''Java Concurrency in Practice''. Addison Wesley Professional, 2006, Section 3.4 ...

objects have value semantics trivially, and in the presence of mutation, an object with value semantics can only be uniquely-referenced at any point in a program. The concepts that are used to explain this concept are

extensionality In logic, extensionality, or extensional equality, refers to principles that judge objects to be equal if they have the same external properties. It stands in contrast to the concept of intensionality, which is concerned with whether the internal ...

definiteness In linguistics, definiteness is a semantic feature of noun phrases, distinguishing between referents or senses that are identifiable in a given context (definite noun phrases) and those which are not (indefinite noun phrases). The prototypical ...

, substitutivity of identity, unfoldability, and referential transparency.

References

Programming paradigms {{Compu-prog-stub