FAuSt

Functional Audio Stream

A pure functional MusicProgrammingLanguage

https://faust.grame.fr/

Looks really good. I want to get into it. (When I get some time)

Lets you write synths, much like PureData or SuperCollider

Also compiles to many different platforms. Including PureData, CeePlusPlus and WebAudio

And can be used for making AudioPlugins