[plt-scheme] procedure instrospection

hi,

i haven't been able to find in the documentation procedures to get
information about defined procedures or macros, other than arity. i'd be
interested in getting, given a (exported) procedure/macro's name and
module:

- argument names (as given in its definition's formals) (or,
  alternatively, the proc source code, from which i can get that).
- filename and line number of definition (some time ago i found
  something similar, but cannot anymore).
- callees and callers of the given procedure (given the former i could
  compute the later, i guess).

is there a way of getting any of the metadata above from the MzScheme
REPL?

thanks!
jao
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