spec-memory.md drops (set (get m k) v) from the assignable forms: a map has an
upsert of its own, put, which either inserts or replaces, so there is no store
into a lookup - and an absent entry has no location to store into anyway.
The compiler still parsed it into an Ast.Pkey and refused it downstream as
unimplemented, milestone 6, which is the wrong reason for something that is
never arriving. The place form is gone from ast, tast, load, check and emit,
and the parser refuses the shape where it is written, with the reason and a
pointer to put.
Do not extend nREPL with registers -- the protocol is trivial, the
implementation is a whole debugger. Emit DWARF from the LLVM backend
and use lldb-dap with dape; no adapter is written. C layout with no
object headers means DWARF describes Flan structs exactly, so lldb
needs no plugin or formatters.
Reload mostly works with DAP for free: lldb watches the loader
rendezvous and re-resolves breakpoint specs against new modules. The
gotcha is our own never-unload rule -- N redefinitions leave N copies
all claiming the same source line, so one breakpoint resolves to N
locations. Needs per-generation DWARF source identity plus a reload
agent that disables superseded locations.
Cuts the instrumentation-based step debugger, the most expensive piece
of milestone 8. Knock-on: &env stops being urgent, and the shadow stack
shrinks to serving nREPL backtraces and restart enumeration.
