IDL

IDL is an acronym that can refer to more than one technology in computing. It is commonly used to denote both an interface definition language used in distributed systems and a proprietary programming language for data analysis and visualization.

Interface Definition Language (IDL) is a language-neutral specification used to declare the interfaces that software components expose to clients. An IDL file describes data types, interfaces, methods (operations), and exceptions, without tying them to a specific implementation language. In middleware such as CORBA and DCE/RPC, IDL serves as a contract between client and server. An IDL compiler generates language bindings, producing client stubs and server skeletons in target languages (for example C++, Java, or Python) and ensuring that calls across language boundaries are well-typed. IDL supports primitives, structs, enums, unions, sequences, arrays, strings, and type aliases; it also supports interface inheritance and exception definitions. The IDL is usually mapped by a middleware-specific compiler to the communication protocol used by the middleware, so IDL by itself does not define a network protocol.

Interactive Data Language (IDL) is a proprietary high-level language and environment for data analysis and visualization. Developed by Research Systems, Inc. (RSI), IDL is array-oriented and features an interactive development environment, built-in plotting and graphics, and a rich standard library for numerical, statistical, and I/O operations. It is widely used in scientific fields such as astronomy, remote sensing, meteorology, and medical imaging, where rapid data exploration and visualization are important. Programs in IDL are typically written in .pro files and run in an interpreted environment.

Because IDL can refer to distinct technologies, its meaning is determined by context, with IDL most often indicating either the Interface Definition Language associated with middleware or the Interactive Data Language used in scientific computing.