slippery chicken documentation - OSC

## slippery chicken and OSC

Available on Mac OSX and Linux with SBCL only:

Using the `(osc-call)` function, slippery chicken can receive and evaluate any arbitrary Lisp code sent over a UDP network (i.e. via OSC). The primary application here is to integrate slippery chicken and e.g. MaxMSP. One possibility would be to combine the two software systems to generate scores on the fly via an interface controlled by musicians. See the video below for an example of this in practice.

For an example MaxMSP patch, see osc-test.maxpat (in the examples folder of the documentation). You'll also need osc-sc-eval.maxpat. Simon Bahr got this working in PD using the zexy and mrpeach libraries. The abstraction you can use is osc-test.pd (also in the examples folder) and the test is osc-sc-eval.pd.

To get slippery chicken to accept and process Lisp calls over OSC, make sure you're in the slippery chicken package and simply type `(osc-call)`. At this point the Lisp interpreter gives up control to OSC but will process commands as they are received (and print them if you call with `:print t`). Send a quit message (to the osc-sc-eval abstraction if using MaxMSP) to return to the Lisp interpreter.

For those who don't have MaxMSP but would like to use another OSC host to communicate with slippery chicken, the following screen shot of the osc-sc-eval MaxMSP abstraction should help:

### Return values

Lisp returns the results of function calls via OSC as a list, so the most appropriate receiving object (e.g. what's connected to the left outlet of osc-sc-eval.maxpat) to display the results is a message box. However, connecting straight to any object that can handle numbers is fine if your function returns a number. Any function which returns T or NIL will automatically be modified to return 1 or 0 instead by slippery-chicken's `osc-eval` Lisp function. More complex return objects will probably just return the printed version of their internal structure, which is not so useful, so we're really limited to simple return types such as lists, symbols, and numbers.