| name | transpile-vet |
| description | Run the Rust→Mycelium transpiler WITH its real-toolchain vet loop (M-1000/M-1001, kickoff trx2): transpile targets, `myc check` every emitted `.myc`, and read the two honesty-split metrics — `expressible_fraction` (text emitted) vs **`checked_fraction`** (myc-check-clean, the number that matters). Per the M-991 verdict (DN-34 §8.7–§8.8, `Empirical`): the transpiler is a **gap-profiling instrument, not a bulk porter** — emitted `.myc` is a `Declared` starting point until a differential upgrades it; a mostly-gapped result is a successful, honest output (G2/VR-5). |
| when_to_use | Use when assessing how much of a Rust crate/module the toolchain can already express (before a port), when profiling which gap classes block a port target (M-993 semcore, the M-1006 ladder), or after changing the transpiler/emitter to measure the real effect. NOT for producing "finished" ports — that claim needs the differential. For the committed draft corpus + graduation workflow, use /myc-drafts instead. |
| allowed-tools | Bash(just transpile-vet:*), Bash(scripts/checks/transpile-vet.sh:*), Bash(cargo run:*), Bash(cargo build:*), Bash(cargo test:*) |
transpile-vet
The operational form of M-1000/M-1001 (crates/mycelium-transpile): the transpile → myc check
→ classify loop that turned "coverage" from an emission heuristic into a toolchain-checked number.
Run it
just transpile-vet <input.rs|input-dir> <out-dir> # the wrapper (recommended)
bash scripts/checks/transpile-vet.sh <input> <out> # same thing, direct
The wrapper builds the myc-check oracle once and hands the binary to the transpiler via
MYC_CHECK_CMD — never pay a nested cargo run per file. Direct CLI (when you need flags):
cargo run -p mycelium-transpile -- --vet <input.rs|input-dir> <out-dir>
Directory inputs: every target gets its own out-dir if you loop crates yourself — batch mode warns
loudly on stem collisions (12 stdlib crates all have lib.rs) and last-write-wins.
Read the output
| Artifact | What it is |
|---|
<stem>.myc | the emitted draft — Declared, a starting point, never a port |
<stem>.gap.json | per-item gaps: 17 closed Category classes + reason + source location |
vet.json | per-file vet records: exit class (0 ok · 2 parse · 3 check · 64 usage · 66 io) + diagnostic |
summary.json / union.gap.json | dir-mode aggregates |
The two metrics — never conflate them (VR-5):
expressible_fraction — items for which some text was emitted. Historically over-counted
(emissions that poison the checker); useful only as an upper envelope.checked_fraction — items in files whose entire emitted .myc is myc-check-clean.
File-gated, honestly conservative (a failing file credits 0; denominator = non-test top-level
items, so checked ≤ expressible always). This is the port-planning number.- An unknown exit code / signal classifies
ToolUnavailable and is never counted clean (G2).
Honesty rules (bind every use)
- Emission is
Declared; a vet verdict is Empirical (measured, this toolchain, this
commit). Only a Rust-oracle differential upgrades a draft beyond that — see /myc-dogfood and
DN-26's stage conventions.
- Never fix a gap by fabricating a body the emitter can't faithfully lower — fallback arms return
Err(GapReason) (the DN-34 §8 honesty-correction precedent). New emission paths trace to a
production in docs/spec/grammar/mycelium.ebnf.
- Reserved-word/
use handling is guard-first (src/reserved.rs, declaration sites included —
PR #1207): a collision is a gap, not an emit-and-hope.
- If you publish numbers (a claim), record them append-only in DN-34 §8.x with the commit SHA
and denominators — numbers are true as dated; a later emitter change does not rewrite them.
Calibration (so you don't re-derive it)
Wave-1 ground truth (DN-34 §8.9, 2026-07-06): union checked_fraction 3.7% over the 17-target
boot10 port surface; best stdlib target 33.3% (tiny), semcore ≤2.4%. The residual 812-gap worklist
(type-coverage 322 · Impl 119 · Import 117 · Struct 80 · GenericBound 59 · tail) is the M-1006
ladder's input. Expect profiling value, not porting value, until those classes close.
