Invariants: A Powerful Tool for Writing Correct Code
This article explores the concept of 'invariants' in programming and their applications. Starting with a small example—writing a binary search variation that computes the insertion point—the author demonstrates how defining and maintaining invariants leads to correct code. Invariants, the article explains, are properties that hold true throughout a system's dynamic evolution, simplifying reasoning by avoiding the complexities of considering numerous execution paths. Examples from projects like Cargo, rust-analyzer, and TigerBeetle illustrate the benefits of using invariants in large systems, such as improved maintainability and performance. The author concludes by summarizing the importance of invariants in both small-scale and large-scale programming, highlighting their value in writing correct and efficient code.
Read more