[racket] Question about path/param-path function

All,

First here is the code I entered in the interaction window.  The question I have are about these lines:
> (require xml net/url)
> (define u (string->url "http://localhost:8080/foo/testing"))
> (url-path u)
'(#<path/param> #<path/param>)
> (map path/param-path (url-path u))
'("foo" "testing”)

I took an online course on Systematic Programming and it used Racket for its examples.  Well, actually it used the intermediate learning language for the class.  now I am trying to learn Racket.
The questions:
1. Take a look at the fourth line.  What is this called?  Is this a list of references or pointers?
2. I am trying to find if help-desk information about path/param-path function, but I have not been able to find any.  This function returns returns the resolved parts of the path of a URL.  What is the proper term for taking the list in line four and returning the list in line five?
3.  What is the proper term for what the function url-path returns?
4.  Does anyone have an example of using the results from line 4 as part of a check-expect test?


David Novogrodsky
david.novogrodsky at gmail.com
http://www.linkedin.com/in/davidnovogrodsky