(However, I suspect that you didn't *really* mean (quote var) in your original code, or? If you didn't, then of course my simpler syntax-rules macro isn't what you want.)
On Wed, Apr 26, 2023 at 7:20 PM Mikael Djurfeldt <mik...@djurfeldt.com> wrote: > How about: > > (define-syntax eval-var > (syntax-rules () > ((_ var) var))) > > ? > > Then you don't need to import (ice-9 local-eval) and re-export things from > there. > > Just for elucidation: > > The reason why we chose the syntax-case macro system for Guile was that it > *both* gives you hygiene *and* quite a lot of control. The reason why the > original code didn't work (your first post in this thread) is that > "(the-environment)" was expanded in the lexical context where it was > written (the Scheme+ module), > > However, syntax-case gives you the ability to insert that identifier into > the context of the expansion instead: > > (define-syntax eval-var > (lambda (x) > (syntax-case x () > ((_ var) > (with-syntax ((the-environment (datum->syntax #'var > 'the-environment))) > #'(let ((env (the-environment))) > (local-eval (quote var) env))))))) > > (It's the datum->syntax form which gives the lexical context of var to > the-environment.) >
