Some people are probably aware of this but this seemed really cool to me, if you are using cmask you can simply insert the results of cmask score compilation into your emacs buffer with a plain csd or sco file like this:
1) create a script with the contents
#!/bin/bash
cat /dev/stdin > ecmask_input
cmask ecmask_input ecmask_output > /dev/null #remove the redirection to /dev/null for diagnostic purposes if needed
cat ecmask_output.sco
rm ecmask_input > /dev/null
rm ecmask_output.sco > /dev/null
2) place it into a file called, say, ecmask into a directory thats in your PATH and then in emacs in the same buffer you are editing your score in place say
f 0 10
p1 const 1
p2 const 1
p3 const 1
p4 const 1
mark the whole region containing cmask source and the press C-u M-| and type ecmask into the minibuffer and voila the cmask part is replaced with the generated csound score! I can think of many other ways of using this feature with csound.