On Sat, Mar 20, 2010 at 03:13:45PM +0100, szgyg wrote: > Josef Wolf wrote: > >I am trying to understand the defstruct macro from the "teach yourself > >scheme in fixnum days" tutorial, which can be found in chapter 9 at > >http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme-Z-H-11.html#node_chap_9 > > > >My first question is of a more generic type. For a better understanding > >how macros work, I'd like to have a way to show what expansion a macro > >would generate when it would be used. E.g., I'd like to do something > >like > > > > (show-expansion (defstruct tree height girth age leaf-shape leaf-color)) > > > >and get what the expansion of this macro would produce: > > > > (begin > > (define make-tree > > (lambda fvfv > > [ ... and so on ... ] > > Use the trick from the inexplicable JRM's Syntax-rules Primer for > the Merely Eccentric[1], wrap the output with quote: > > ... > (let ((ff (map (lambda (f) (if (pair? f) (car f) f)) > ff))) > `'(begin > ; ^ > (define ,(string->symbol > (string-append "make-" s-s)) > ...
Ah, sounds reasonable. Thanks! > [1] > http://www.xs4all.nl/~hipster/lib/scheme/gauche/define-syntax-primer.txt I will save this link for later, since this stuff is still too advanced for me. In the meantime, I'll be looking for something that's more entry-level...
