SLang is an interpreted language that was designed from the start to be easily embedded into a program to provide it with a powerful extension language. Examples of programs that use SLang as an extension language include the Jed text editor, the slrn newsreader, and sldxe (unreleased), a numerical computation program. For this reason, SLang does not exist as a separate application and many of the examples in this document are presented in the context of one of the above applications.

SLang is also a programmer's library that permits a programmer to develop sophisticated platform-independent software. In addition to providing the SLang extension language, the library provides facilities for screen management, keymaps, low-level terminal I/O, etc. However, this document is concerned only with the extension language and does not address these other features of the SLang library. For information about the other components of the library, the reader is referred to the \slang-library-reference.