If one were to create a GUI frontend for SoX how could I do that using current existing code that can be translated into a GUI front end to use all the features that SoX has and uses? And also be able to use it to pass real-time effects to input sources to stuff like PulseAudio on the fly as the user needs it? I would like to make a plugin for PulseEffects that makes use of SoX as the backend to make it easy for such things with SoX.
From the manual: "If you need an interactive graphical editor, use audacity(1)"
But check out https://github.com/prof-spock/SoX-Plugins which reimplements libsox in C++ and floating point as VST3 plugins.