Dan's implementation is fascinating, but I'm unsure if it qualifies as "truly novel" since I _think_ I've seen something like this before. I wish I could rememb

Dan's implementation is fascinating, but I'm unsure if it qualifies as "truly novel" since I _think_ I've seen something like this before. I wish I could remember where, and a few quick searches have turned up no results. As he mentioned, thread-local-storage (the other "TLS") in CommonLisp is provided by dynamically scoped variables [1], but this similar functionality is being accomplished elsewise. Though this way of getting TLS may lack some of benefits of full dynamically scoped variables, I've got a wild, unsubstantiated hunch that this way may have better performance than full blown dynamic scoping due to less overhead. The fun part is, this way of doing things (i.e. without dynamic scoping built in) is essentially doing "user-directed scoping" that is vaguely similar to things like "SoftTyping" [2] and "SuccessTyping" [3,4] which are basically "user-directed typing". [1] https://en.wikipedia.org/wiki/Thread-local_storage#Common_Lisp_.28and_maybe_other_dialects.29 https://en.wikipedia.org/wiki/Thread-local_storage#Common_Li... [2] http://c2.com/cgi-bin/wiki?SoftTyping http://c2.com/cgi-bin/wiki?SoftTyping [3] http://www.it.uu.se/research/group/hipe/publications.shtml http://www.it.uu.se/research/group/hipe/publications.shtml [4] http://www.it.uu.se/research/group/hipe/publications.shtml http://www.it.uu.se/research/group/hipe/publications.shtml