> Also note that lack of hygiene is actually a useful feature - it allows macros to capture variables from code passed to it as well as the environment they exp

> Also note that lack of hygiene is actually a useful feature - it allows macros to capture variables from code passed to it as well as the environment they expand it. Some cool stuff can be done that way (some uncool foot-shooting too, though). Doug Hoyte's excellent book _Let Over Lambda_ has a lot of examples.