A procedural macro receives a flat stream of tokens. It cannot ask “is this a struct or an enum?” or “what are the field names?” at the token level. The syn crate parses that token stream into a typed syntax tree—DeriveInput, ItemFn, Expr, Type—so the macro can navigate the structure with Rust’s pattern matching and…
Rust has three kinds of procedural macros, and the derive macro covered in the previous chapter is only the first. The other two—attribute-like macros and function-like macros—share the same crate type and the same TokenStream interface, but they are invoked in different syntactic positions and receive different inputs. An attribute-like macro is written as #[route(GET,…
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Derive macros are the most common kind of procedural macro in Rust. When you write #[derive(Debug, Clone, Serialize)], the compiler invokes a procedural macro for each of those names, passing the token stream of the annotated item, and expects a token stream of new items to append to the surrounding module . The macro is…
The question of whether to write a native C extension or use Dart FFI is not a question about whether native code is faster than Dart. In a pure computational sense, C is faster for the same algorithm because it compiles to machine code without the Dart VM’s overhead. The real question is whether the…
Dart’s server-side ecosystem has no single ORM that dominates the way Hibernate dominates Java or ActiveRecord dominates Ruby. Instead, the landscape is a spectrum: raw drivers that speak the wire protocol, query builders that generate dialect-correct SQL, and ORMs that map tables to typed Dart classes with code generation. The choice between them is a…
Protocol Buffers is a language-neutral, platform-neutral mechanism for serializing structured data. In Dart, using it requires two distinct pieces: the protoc compiler with the Dart plugin, which generates the Dart source code from a .proto file, and the protobuf runtime package, which the generated code depends on to serialize and deserialize the messages . The…
A microservices architecture splits an application into small, independently deployable services that communicate over a network. The communication protocol matters: HTTP/JSON is flexible but lacks a strict contract, while gRPC provides a strongly typed interface defined in Protocol Buffers, generated client and server stubs, and native support for streaming in both directions. Dart’s package:grpc implements…
A WebSocket is a persistent, bidirectional connection between a client and a server, established through an HTTP upgrade handshake and then maintained as a raw TCP socket. Unlike HTTP, where the client must ask for every response, a WebSocket lets either side send a message at any time. Dart’s standard library provides first-class support for…
A component test that renders markup and asserts on the output is only half a test. The other half is the interaction: the user types into a field, clicks a button, presses Escape, tabs through a form, or holds a modifier key while clicking. React Testing Library’s userEvent library exists to simulate those interactions with…
React Testing Library (RTL) is not a test runner. It is a set of utilities that render a React component into a DOM and provide queries for finding elements the way a user would find them—by role, by label, by text—rather than by implementation details like component state or class names . The library’s guiding…