I don't know of a paper, but on the Tcl wiki there is some discussion of the "non-recursive evaluation" (NRE) engine that enables these features [1]. More forma

I don't know of a paper, but on the Tcl wiki there is some discussion of the "non-recursive evaluation" (NRE) engine that enables these features [1]. More formal descriptions of the new coroutine [2] and tailcall [3] commands are listed, among others, here [4]. 1. http://wiki.tcl.tk/37253#pagetocbefb5a57 http://wiki.tcl.tk/37253#pagetocbefb5a57 2. http://www.tcl.tk/cgi-bin/tct/tip/328 http://www.tcl.tk/cgi-bin/tct/tip/328 3. http://www.tcl.tk/cgi-bin/tct/tip/327 http://www.tcl.tk/cgi-bin/tct/tip/327 4. http://wiki.tcl.tk/21276 http://wiki.tcl.tk/21276 Update: more details on the NRE implementation are available here [5] at the contributing author's site; anonymous login required. 5. http://msofer.com:8080/wiki?name=NRE http://msofer.com:8080/wiki?name=NRE