Surmulot can be considered from several points of view:
Here the entry point is Emacs and its Csound-x package for Csound composition.
Surmulot provides interactive widgets extending Csound-x with graphical editors for musical data such as musical phrases and envelopes, or interactive controls (like OSC-driven sliders).
Surmulot also makes it possible to generate, edit and play MIDI data from Emacs, using either Csound or Timidity as soft synthesizer.
Here the entry point is MuO, a Squeak application for music composition.
MuO homepage: http://www.zogotounga.net/comp/squeak/sqgeo.htm
Surmulot allows Emacs to be integrated as the default text and files editor for MuO. It makes it also possible for Squeak to access the system shell via Emacs instead of using OSProcess.
It also gives MuO access to the full power of Csound-x.
Surmulot can also be considered as an unified programming environment in which applications can use both Csound-x and MuO as libraries.
An example of such an application is Eshell, where a wealth of functionality is made available via simple commands see Eshell.