"let*" and "render"

[danielgerigk]

In chapter 8 ("Writing Macros"), you could include a few words on the meaning of "let*". Also, the function "render" is not properly introduced (and perhaps could even be replaced by "println" altogether).

[pyrmont]

I was confused by this as well. I wrote up an explanation of what's going on with let* that might be helpful to others.