Anyone who would like to use list comprehension forms, or read about how Lisp enables them, might find these papers interesting:

Implementation of a "Lisp comprehension" macro by Guy Lapalme http://rali.iro.umontreal.ca/rali/sites/default/files/publis...

Simple and Efficient Compilation of List Comprehension in Common Lisp by Mario Latendresse http://www.ai.sri.com/~latendre/listCompFinal.pdf