On Wed, Oct 29, 2014 at 5:50 AM, Konrad Hinsen <konrad.hin...@fastmail.net> wrote: > Sam Tobin-Hochstadt writes: > > > > This suggests that if I want my single-form module to be handled exactly > > > like a multi-form module, my single form must expand to something else > > > than #%plain-module-begin. Fine. But who or what decides what my single > > > form becomes when it is "partially expanded in a module-begin context" ? > > > > This always happens in a single-form module. The macro system > > partially-expands the macro to see if it turns into a version of > > #%module-begin. > > Fine, but how? Where are the rules that lead to > > (displayln (foo 42)) > > being partially expanded to > > (#%plain-module-begin ...)
The rule is that for anything like: (module m lang (form ...)) `form` is expanded until it either produces `#%plain-module-begin` or another core form. In the former case, it just continues, in the latter case, it wraps the whole thing with `#%module-begin` as exported from the specified language, and then expands that. In your particular example, it will expand (displayln (foo 42)) to (#%app displayln (foo 42)) and then to (#%module-begin (#%app displayln (foo 42))). > Are they part of the language definition? More specifically, I am > looking for a way to override them. I'm not sure exactly what you want to override here. Sam ____________________ Racket Users list: http://lists.racket-lang.org/users
