# Step 1 — Phase-0 scaffolding (tag: `step1`)

Commit `18e40b8` — "Phase-0 scaffolding — M2c module-skeleton compiler,
4/4 tests green" (29 files, +2756).

## Goal

Prove the toolchain end to end before any language work: Coco/R grammar
→ generated scanner/parser/driver → `gm2 -fiso` build → test runner,
all inside a new `m2c/` folder.

## What was built

- `m2c/M2c.atg` — module skeleton only:
  `MODULE <name> ; [ BEGIN ] END <name> .`, with an inline
  closing-name check (error 202). No declarations, statements, or
  symbol table.
- `m2c/compiler.frm` — minimal driver (listing + `StoreError`,
  `ChangeExtension`, `FileIO`-based main), custom message for 202.
- `m2c/scanner.frm`, `m2c/parser.frm` — proven FileIO-based Coco/R
  frames, reused from the earlier CocoGm2 work.
- `m2c/FileIO.def/.mod` — I/O library, reused as-is.
- `m2c/build.sh` — regenerate (`CRFRAMES=. $CRBIN -m -C M2c.atg`,
  `CRBIN` overridable), compile with `gm2 -fiso`, link via the
  two-phase module-list workaround; produces `./M2c`.
- `m2c/run_tests.sh` — `expect_ok` / `expect_fail` (checks `.LST`
  message text, since listings show messages, not codes).

## Tests — 4/4

| test | result |
| ---- | ------ |
| ok_minimal | `MODULE M; BEGIN END M.` accepted |
| ok_nobegin | `MODULE M; END M.` accepted |
| bad_mismatch | `END N` rejected with 202 |
| bad_syntax | missing `.` rejected with syntax error |

Both `SemError` (202) and `SynError` paths verified working.

## Notes

- Grammar name `M2c` keeps generated modules short
  (`M2cS`/`M2cP`/`M2c`, no Coco/R truncation surprises).
- `m2comp/coco-chatgpt-doesntwork/` explicitly excluded from all work.