The KoreLogic Expression Language Library (libklel) is a C library that provides a simple expression language that can be embedded in other programs. It does not implement a full programming language, but rather a simpler expression language called KL-EL that is designed to provide arithmetic and logic operations in situations where embedding a full programming language would be overkill. KL-EL can access functions and variables exported from the embedding program, and is statically and strongly typed, which helps ensure that expressions are valid before they are executed. The embedding API is easy to use, and the library itself is very small.
MMLi is a simple Music Macro Language interpreter written in ISO C99. The Music Macro Language originated in 8-bit BASIC implementations (as part of the “PLAY” command), and can still be found in modern BASICs (like QB64) and in system software (like FreeBSD's spkr.c driver.) This interpreter features an example "mmlitest" program which can be used to translate MML sequences into beep(1) commandline arguments.