A recent technical assessment highlights the deep structural similarities between Rust and Swift, noting that both languages incorporate advanced features like tagged enums, powerful generics, and LLVM-based compilation. The author, reviewing their experience with both languages, posits that Swift effectively mirrors much of Rust's feature set, albeit with a distinct philosophical orientation.
According to the analysis published on nmn.sh, the primary divergence lies in the default memory management strategy, framing Rust as a bottom-up systems language and Swift as a top-down high-level language. Rust prioritizes raw speed by default, often requiring explicit invocation of Copy-on-Write (Cow) semantics, whereas Swift defaults to Copy-on-Write for value types, simplifying concurrent access.
This difference in default settings mandates differing levels of developer ceremony; Rust requires extra steps to utilize higher-level abstractions, while Swift demands extra ceremony to opt into Rust-like borrowing and moving for performance gains. The report suggests Rust is faster by default, while Swift is simpler by default, optimizing for different stages of development.
Furthermore, the author details how Swift often cloaks powerful functional concepts, such as pattern matching, within familiar C-like syntax, exemplified by the `switch` statement functioning identically to Rust's `match` expression. This syntax choice reportedly aids adoption among developers accustomed to older paradigms.
Regarding null safety, Swift's optional types (`T?`) offer compiler-enforced checks similar to Rust's `Option<T>`, but Swift transparently converts non-optional types to optionals where needed, reducing boilerplate. Similarly, Swift's `do-catch` structure masks Rust's `Result` type mechanism for error propagation.
While both languages enforce strong compile-time safety, Rust forces explicit handling of recursive types using constructs like `Box<>`, making memory layout explicit. Swift abstracts this concern via the `indirect` keyword for enums, handling the necessary indirection automatically, reflecting its pragmatic design for interfacing with Objective-C.
Ultimately, the assessment concludes that Swift, being less 'pure' due to its need to replace Objective-C, incorporates a wider array of built-in features, including classes and actors, supporting a model of 'progressive disclosure' as developers advance. This breadth makes Swift highly suitable for UI and server development, while Rust retains an edge in areas demanding absolute low-level control, such as operating system kernels.
