samth made a pointer to <a href="http://srfi.schemers.org/srfi-72/srfi-72.html">http://srfi.schemers.org/srfi-72/srfi-72.html</a> It does not look like guile racket etc. have implemented this yet. Am I wrong? This is precisely what I'm after! <div class="gmail_quote">On Tue, Jul 10, 2012 at 5:26 PM, Ludovic Courtès <<a href="mailto:ludo@gnu.org" target="_blank">ludo@gnu.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi, Matthew Flatt <<a href="mailto:mflatt@cs.utah.edu">mflatt@cs.utah.edu</a>> skribis: <div class="im"> > It's natural --- but not correct --- to think that #` is responsible > for hygiene, in which case `(f #'x)' should keep the given `x' separate > from the `let'-bound `x' in the result. </div>[...] <div class="im"> > If you change the example to > > #lang racket > (begin-for-syntax > (define-syntax-rule (f body) > #`(let ([x 1]) body))) > (define-syntax (m stx) > (with-syntax ([zz (f x)]) #`(let ([x 2]) zz))) > (m) > > so that `f' is used as a macro instead of a function, then you get 2, > since the macro-expansion of `(f x)' keeps the `x's separate. </div>Interesting. Thanks for the clarification and examples. Ludo’. </blockquote></div>