There's an edge case of 'module' when only one form is provided which results in that form being partially expanded to determine if such expansion would lead to a #%plain-module-begin form. Otherwise (more than one form provided) they are wrapped in #%module-begin with no partial expansion occurring.
I think this might be causing the discrepancy you witnessed. >From the docs (https://docs.racket-lang.org/reference/module.html): If a single form is provided, then it is partially expanded in a module-begin context. If the expansion leads to #%plain-module-begin, then the body of the #%plain-module-begin is the body of the module. If partial expansion leads to any other primitive form, then the form is wrapped with #%module-begin using the lexical context of the module body; this identifier must be bound by the initial module-path import, and its expansion must produce a #%plain-module-begin to supply the module body. Finally, if multiple forms are provided, they are wrapped with #%module-begin, as in the case where a single form does not expand to #%plain-module-begin. (This response was adapted from one of my earlier replies to the mailing list. Search racket-users for "perplexed by macro-expansion behavior near #%module-begin" for more context). Best, Michael On Sat, Jan 2, 2021 at 8:26 PM Sage Gerard <[email protected]> wrote: > Why does Racket handle modules with exactly one form differently? > > I ran into a bug where modules in my module language won't expand if the > modules have exactly one form, so I'm just curious. > > (Wild guess: It's Racket's way of checking for a shortcut to end expansion > earlier) > > *~slg* > > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/OVvZ0OK4_PfyvXCWfuvzDWBM5-ellmDvNmWchVmsCwAJb_rbSZkCkyraakcGsEMSCl2BsLsWtMXFhQcXY75IKhYiYYGQQEI7lVXLgGBbTCc%3D%40sagegerard.com > <https://groups.google.com/d/msgid/racket-users/OVvZ0OK4_PfyvXCWfuvzDWBM5-ellmDvNmWchVmsCwAJb_rbSZkCkyraakcGsEMSCl2BsLsWtMXFhQcXY75IKhYiYYGQQEI7lVXLgGBbTCc%3D%40sagegerard.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CACehHmC0ZMqoGv8SF8jiEkLJfE4SL1SKsCuJUT1W2qYDORo19Q%40mail.gmail.com.
