latebound

Latebound, or late binding, is a term in computer programming that describes resolving a method call, property access, or other operation at runtime rather than at compile time. In late binding, the exact code to be executed is determined during program execution, often based on the actual type of an object encountered at runtime.

Late binding is common in dynamically typed languages, where types are associated with values at runtime, such as Python and JavaScript, where method lookups occur as code runs. In statically typed languages, late binding can be achieved through mechanisms such as reflection, dynamic dispatch, or language features that defer binding until runtime. In the context of component object models, technologies like COM provide late binding through interfaces such as IDispatch, allowing clients to invoke methods on objects without compile-time knowledge of their interfaces.

Practical use of late binding includes plugin architectures, scripting within applications, and interoperation with components whose types are not known at compile time. It enables greater flexibility and extensibility, as new types can be integrated without recompiling existing code. However, late binding typically incurs overhead from lookup or dispatch operations, reduces compile-time type safety, and may result in runtime errors that would be caught earlier with early binding. Performance optimizations, when possible, include caching resolved call targets or using more static interfaces to limit dynamic binding.

Late binding contrasts with early binding, where type information is resolved at compile time, enabling stronger type checking and faster execution. Both approaches have trade-offs and are chosen based on the desired balance between safety, performance, and flexibility. See also early binding, dynamic typing, reflection, and dynamic dispatch.