Embeddable Common Lisp is a LGPL Common Lisp

Common Lisp

Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard document ANSI INCITS 226-1994 , . From the ANSI Common Lisp standard the Common Lisp HyperSpec has been derived for use with web browsers...

 implementation aimed at producing a small-footprint Lisp system that can be embedded into existing C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

-based applications. It is able to create stand-alone ELF

Executable and Linkable Format

In computing, the Executable and Linkable Format is a common standard file format for executables, object code, shared libraries, and core dumps. First published in the System V Application Binary Interface specification, and later in the Tool Interface Standard, it was quickly accepted among...

 executables from Common Lisp code and runs on most platforms that support a C compiler

Compiler

A compiler is a computer program that transforms source code written in a programming language into another computer language...

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Because it compiles Common Lisp to C, it also features an FFI

Foreign function interface

A foreign function interface is a mechanism by which a program written in one programming language can call routines or make use of services written in another. The term comes from the specification for Common Lisp, which explicitly refers to the language features for inter-language calls as...

system, including support for inline C to be used or generated from Common Lisp. Inline C FFI combined with Common Lisp macros and custom SETF expansions yield a compile-time preprocessor.