(defmacro do-grid [[r rows c cols] & body] ...) — positional names, a [ ]
pattern wherever an argument is a vector, and & for the tail. The reading of
the list lives in Expand, below both sides that need it: Parse turns it into
the bindings a macro body opens with, and Macro checks a call against the same
reading before expanding it, so arity and shape are refused with the call's own
location rather than with the Loc.from_macro stamp every node of an expansion
carries.
The breaking half: [args] used to bind the whole argument list and now binds
the first argument. The whole list is [& args], and every defmacro in the tree
— prelude, vendor, tests, the elisp fixtures — was migrated to it. One grammar,
not a legacy mode.
Load.program takes forms: it reads the import forms, resolves them with the
one resolver it always had, and parses the file with the packages' macros in
front of it. The refusal said this needed a second import resolver at the Form
level. It did not notice that the file being compiled is parsed before Load
runs too, so no shape of the feature could have left import resolution where
it was.
Names arrive qualified, as a defn's do. (mac/twice 4) is a call and (twice 4)
is an unknown name.
Stopped mid-task: dune test was never run and the acceptance wiring is
unfinished. HANDOFF-macros.md has what is left.
