# Session save — 2026-09-24 (part b): forward procedure calls

Continues `docs/session-2026-09-24.md`. HEAD after this: `v3-forward-calls`
(+ the showcase). Suite **111/111**.

## Landed

- **`v3-forward-calls`** (`6cd5ef9`) — within-module forward procedure
  calls solved for self-hosting; `M2S` and `M2P` now compile clean
  under V3. Details in `docs/summary_forward-calls.md`. In short:
  - CR's parser output hides its forward declarations in a comment by
    default (`-m` suppresses `FORWARD`); V3 is single-pass. Generate
    without `-m` for V3 (real `FORWARD`s), keep `-m` for the gm2
    stage-1 build (gm2's link-time pass rejects `FORWARD`).
  - Added: empty `ELSIF … THEN` bodies, `BITSET` predef
    (`SET OF [0..15]`), typed set constructor `BITSET{…}`, and a
    driver file-handle leak fix (`compiler.frm` now closes each source;
    the host FileIO caps at 16 open files).

## Self-compilation status (sources generated without `-m`)

| Source | Errors under V3 |
|---|---|
| `SymTab` | 0 |
| `QbeGen` | 0 |
| `M2S` (scanner) | 0 |
| `M2P` (parser) | 0 |
| `M2.mod` (driver) | 12 |

## Remaining for the driver `M2.mod`

- **Nested modules** — `ListHandler` is a Wirth-style local
  `MODULE … EXPORT StoreError, PrintListing, PrintConsoleErrors,
  ResetErrors`; V3 parses it but marks 230 and does not expose its
  exports. Needs nested-module lowering (prefixed globals/functions +
  the enclosing scope seeing the `EXPORT` list).
- **String building** — the driver builds file names with
  `Strings.Delete`/`Append`. V3's descriptor header is *both* the
  open-array count and the logical string length (`m2setlen`), so once
  `Assign` shrinks it, `Append` past the logical length traps. `Delete`
  alone is safe. Needs either a string-model decision (keep a separate
  length) or a `compiler.frm` rewrite that avoids incremental append.

Then: cross-stage `FileIO` selection and `bootstrap/fixpoint.sh`,
plausibly driven by `M2make`; note the stage-aware CR flags
(`-m` for gm2, no `-m` for V3).

## Showcase

`compiler/tests/showcase13.mod` (exit 42, suite 111/111): `FORWARD`
mutual recursion (`Even`/`Odd`) plus `BITSET` union/membership and the
typed set constructor `BITSET{…}`.

## Resume

```sh
cd /home/eric/Projets/Projets-Modula2/MyWork/m2compiler-V3/compiler
./build.sh && ./run_tests.sh          # gm2 build (-m), expect 111/111

# V3-facing (FORWARD) re-generation + M2P check:
(cd src && CRFRAMES="$(pwd)" /home/eric/Projets/Projets-Modula2/MyWork/CocoGm2/CR -C M2.atg >/dev/null)
./M2 ../stdlib/storage.def ../stdlib/storage.mod \
     ../runtime/syslib/SysShim.def ../runtime/syslib/SysShim.mod \
     ../runtime/syslib/FileIO.def ../runtime/syslib/FileIO.mod \
     src/SymTab.def src/SymTab.mod src/QbeGen.def src/QbeGen.mod \
     src/M2S.def src/M2S.mod src/M2P.def src/M2P.mod /tmp/gap.mod
```