<div class="gmail_quote">2009/2/9 Felix Klock's PLT scheme proxy <<a href="mailto:pltscheme@pnkfx.org">pltscheme@pnkfx.org</a>> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Joe (cc'ing James and plt-scheme)-<div class="Ih2E3d"> On Jan 17, 2009, at 12:26 PM, Joe Marshall wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> On Sat, Jan 17, 2009 at 6:42 AM, James Coglan <<a href="mailto:jcoglan@googlemail.com" target="_blank">jcoglan@googlemail.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> I was wondering whether it's possible to have tail call optimisation when using normal order. I don't want to bang my head against the wall trying to make it happen if it can't be done. </blockquote> To answer your question directly:  it isn't easy and it might not be possible at all.  If anyone *really* knows the answer, it is Will Clinger. I might be a bit behind the times here, but I believe it is still an open question the way you have phrased it.  I'll go out on a limb and suggest that a good explanation is worthy of a degree. </blockquote> </div> If you want to see related work on this topic, you may want to look at the work of Bakewell and Runciman on this topic. For example: <a href="http://portal.acm.org/citation.cfm?id=351287" target="_blank">http://portal.acm.org/citation.cfm?id=351287</a> (Caveat: I read their papers a few years ago, so maybe their stuff has become out-dated.  But my memory is that they at least referenced Will's work on the topic; they had a chance of being on the right track.)</blockquote> <div> Thanks. I've since moved onto implementing continuations, and I had enough trouble getting my head around the applicative order version that I think trying to implement continuations for normal order would make my head explode... </div></div>