# Step: TopSpeed V3 corpus validation

Tag `v3-topspeed-corpus`. V3 suite **151/151**, fixpoint OK
(unchanged — this touches only the sidecar).

## Why

After self-hosting, the next "normal" step was to exercise the
front-end on a **real corpus**. The historical TopSpeed/JPI V3 corpus
is the natural target: `$HOME/bin/Dos/M2/TS-V3` — **662 files**
(352 `.DEF` + 310 `.MOD`).

V3's own `M2.atg` is the classic/Redux subset and would not take this
dialect (pragmas `(*#...)`, conditional compilation `(*%...)`, `H`/`C`/
`B` literals, `::=`, address constructors `[seg:ofs]^`, `CLASS`/`IS`,
manifest constants, ...).  The project already carries a
**sidecar** grammar for it, `compiler/src/TopSpeed-V3-M2.atg`, whose
deliverable is *parsing* the dialect (unlowered constructs end in the
standard `230`, parse-now / lower-later).

That sidecar had never been compiled and run over the full corpus.

## What was done

1. **Built the sidecar** (`tools/topspeed-grammar/build.sh`) — copies
   the grammar + the V3 frames + `SymTab`/`QbeGen`/`FileIO`, runs
   `CR -m -C`, `gm2 -fiso`, links `build/TSM2`.
2. **Fixed API drift** vs the current `SymTab`/`QbeGen` (the sidecar
   predated several changes):
   - `SymTab.NewArray(e)` → `SymTab.NewOpenArray(e)`;
   - `SymTab.FixPending(t)` / `SetProcRes(t)` now return `BOOLEAN`;
   - `QbeGen.EndModule` now takes the module name.
3. **Three real grammar gaps** the corpus exposed:
   - **tagless variant** `CASE : T OF` (anonymous selector) — TopSpeed
     accepted, the sidecar required a named tag;
   - **manifest constants without `CONST`** (`NAME = value;` at
     declaration level);
   - **trailing `|`** in a variant list (`TRUE: …; | FALSE: …; |`).
4. **Corpus harness** (`tools/topspeed-grammar/corpus.sh`) — runs
   `TSM2` over every `.DEF`/`.MOD` in a scratch tree (so listings never
   touch the corpus) and classifies each file as *parse-OK* (only the
   deliberate `230`/semantic markers) or *syntax-bad* (a real Coco/R
   error).

## Result

| | files |
| --- | --- |
| corpus | **662** (352 `.DEF` + 310 `.MOD`) |
| **parse-OK** (230/semantic only) | **631** |
| syntax-bad | **31** |

Coverage rose **590 → 627 → 631** as the fixes landed.

### Remaining 31 syntax-bad

- **17 use `(*%…*)` conditional compilation** — a lexer feature the
  sidecar does not implement; text inside a disabled block is parsed
  as code.  (Pragmas `(*#…)` are already fine — they lex as ordinary
  `(* … *)` comments.)
- **14 assorted**, e.g. a typed set constructor in an argument list
  (`GetMenu("…", CharSet{'N','P','T'}, ch)`), address constructors,
  and a few files with malformed/commented-out regions
  (`END (*QMLB` …).  Full list in the harness output.

## Reproduce

```sh
cd tools/topspeed-grammar
./build.sh          # -> build/TSM2
./corpus.sh         # -> 631 parse-OK / 31 syntax-bad
```

## Notes

- V3's own compiler (`M2.atg`) and the self-hosting path are untouched;
  the sidecar is a separate grammar built on demand.
- The sidecar now tracks the V3 `SymTab`/`QbeGen` API; if those drift
  again, `build.sh` is where the small patch belongs.

## Files

`compiler/src/TopSpeed-V3-M2.atg` (three grammar fixes),
`tools/topspeed-grammar/{build.sh,corpus.sh,README.md}`,
`.gitignore` (build dir), this doc.