> A macro character is either terminating or non-terminating. The difference between terminating and non-terminating macro characters lies in what happens when such characters occur in the middle of a token. If a non-terminating macro character occurs in the middle of a token, the function associated with the non-terminating macro character is not called, and the non-terminating macro character does not terminate the token's name; it becomes part of the name as if the macro character were really a constituent character. A terminating macro character terminates any token, and its associated reader macro function is called no matter where the character appears. The only non-terminating macro character in standard syntax is sharpsign.
http://www.lispworks.com/documentation/lw50/CLHS/Body/02_add...
That is the system I was alluding to. It’s been a few years since I’ve done anything with CL and so it seems my memory was slightly off.