vpng — the VSL/MSL M1 walking skeleton

VPNG ("vista-ping") is a throwaway VistA config-echo consumer that proves the first full vertical of the VSL/MSL effort end to end. It does exactly one thing:

read the VPNG GREETING parameter at the SYS entity via $$get^VSLCFG, serialise {"greeting":"<value>"} with $$encode^STDJSON, and return the byte string — the golden {"greeting":"hello"}.

That single string, byte-identical on YottaDB and IRIS, is the M1 exit criterion. Everything else in the determinism ledger (KIDS build/install/test-in- place/uninstall, the drift gates) is a presence/equality check around it.

• Layer: v (VistA-specific — it reads VistA config). Declared in repo.meta.json; enforced by m arch check (the waterline v → m rule).
• Requires (KIDS Required-Build chain): the VSL base VSL*1.0*1 → the MSL base MSL*0.1*1. Install in dependency order (MSL → VSL → VPNG).
• Consumes, never edits: v-stdlib (VSLCFG) and m-stdlib (STDJSON, STDASSERT).

Layout

Path	Contents
src/VPNG.m	the one routine — $$ping^VPNG()
tests/VPNGTST.m	the ^STDASSERT suite (golden + seeded-value robustness)
kids/vpng.build.json	the KIDS build spec (routine + Required Build on the VSL base)
dist/kids/VPNG.kids	the committed normalized KIDS export (drift-gated)
repo.meta.json	the committed meta artifact — carries "layer": "v"

Develop

make check-fast                          # fmt/lint/arch + namespaces + engine-access + check-kids (engine-free)
make test  ENGINE=ydb  DOCKER=vehu       # the suite on YDB, over the driver
make test  ENGINE=iris DOCKER=foia-t12   # the suite on IRIS, over the driver
make kids                                # rebuild dist/kids/VPNG.kids via v-pkg

All engine work goes through the m-driver-sdk → m-ydb/m-iris stack (m test --docker, m vista exec, v-pkg) — never raw docker exec.