title: Streams in Common Lisp?
body: <p>Section 3.5 of <em>Structure and Interpretation of Computer Programs</em> describes streams.  Does Common Lisp have such streams built in or is there a good Common Lisp library implementing such streams?</p>
  
  <p>[I mean streams in all the generality presented in section 3.5 of <em>SICP</em>; not just your usual i/o streams.]</p>