eimuuttuva

Eimuuttuva is a term used in Finnish-language computer science and mathematics to denote objects, values, or data that do not change after they are created. The word is formed from ei, meaning "not", and muuttuva, meaning "mutable" or "changing". In practice, eimuuttuva describes immutability, a property valued for predictability, thread-safety, and simpler reasoning about code.

In programming, an eimuuttuva value is immutable: once created, its state cannot be modified. Attempts to alter it typically return a new value or produce an error. Many languages implement immutability by design for certain types (for example, strings in Java or Python). Immutable data structures, such as persistent lists or trees, enable safe sharing across routines and threads, and support functional programming styles.

In mathematics and formal logic, eimuuttuva can describe constants or quantities whose value does not depend on changing variables within a given context. The concept contrasts with mutable quantities that may be altered during computation or over time.

Advantages of immutability include easier reasoning, avoidance of side effects, and improved concurrency. Disadvantages can include higher memory usage and the need to create new objects when changes are needed.

The term is commonly encountered in Finnish technical writing and education and is often used alongside terms such as mutable (muuttuva) and constant (vakio).