[plt-scheme] getting argument identifiers

> The debug functions in unlib do what you want, I think.

Yes. The Unlib "debug.ss" module is basically a bunch of glorified  
print statements that do this kind of thing. Check out the docs to see  
if it fits your requirements:

     http://planet.plt-scheme.org/package-source/untyped/unlib.plt/3/8/planet-docs/unlib/debug.html

-- Dave