Quasiimmutable

Quasiimmutable refers to a state or object that is not strictly immutable but exhibits a high degree of resistance to modification. Unlike true immutability, where an object's state can never change after creation, quasiimmutable objects may allow for some limited modifications, often under specific conditions or through designated methods. The core idea is that the object's state is generally expected to remain constant, and any changes are either rare, controlled, or result in the creation of a new, modified version rather than altering the original.

This concept is frequently encountered in programming languages and data structures. For instance, a data structure might be considered quasiimmutable if its primary operations return a new instance with the changes applied, leaving the original untouched. However, there might be internal mechanisms or specific methods that allow for in-place modifications under certain circumstances, or perhaps the underlying data can be altered through a reference if not carefully managed. The term implies a design choice to favor predictable behavior and prevent unintended side effects, while still allowing for efficiency or specific use cases that might benefit from controlled mutability. The "quasi" prefix signifies that the immutability is partial or conditional.