# Pasta80 Pascal-S validator pilot

`pasta80.atg` describes Pascal-S as implemented by Arzu/Terry's
Coco/R-Turbo-Pascal compiler (1996-97). The reference files
(`Grammars/Pasta80/pasta80.atg`, identical to `Pascual/pascual.atg`
modulo its tags line) are written for a newer Coco/R generation:
attributed rules (`<params>`, `(.. actions ..)`, `SYNC`), so the
pilot is a mechanical port — actions/attributes stripped by script,
`<>` restored where the stripper ate the operator — plus hand fixes,
all diagnosed against `psc` (the Turbo batch interpreter built with
`fpc -Mtp`) as oracle:

1. `|` empty literal from the eaten `<>` (in `RelOp`).
2. Strict `Statement { ";" Statement }` lists (block body,
   `CompStat`, parameter tails) made tolerant.
3. Duplicate `preal` in `RealConst` merged.
4. `WriteArg` string-vs-expression conflict merged into
   `Expression [ ":" ... ]` (after proving `psc` accepts string
   comparisons, so `StrConst` belongs in `Factor`).
5. Mandatory `";"` after every record field relaxed to the tolerant
   list shape.
6. Missing `CASE` statement added whole (`CASE`/`OF`/`|`/`END`,
   labels are `pnumber`/`ident`/`pstring`, no ranges, no `ELSE` —
   each shape probed).
7. `REPEAT` with `","` separators corrected to `";"` (probed:
   `psc` takes semicolons, rejects commas).
8. Bare `READ`/`WRITE` calls: parens made optional (probed).

One benign LL(1) warning family remains (dangling-`ELSE`).

## Build

```sh
./build.sh        # -> build/Pasta80 (build/ is git-ignored)
```

Needs `CR` (Coco/R), `gm2 -fiso`, the `parser.frm`/`scanner.frm`
frames and `FileIO.def/.mod` — all resolved from the environment with
sensible defaults (`CRFRAMES`, `M2LIB`, `CR`, `GM2`).

## Differential results (Pasta80 vs `psc`)

The PascalS accept battery (22 cases) + `tests/deep.pas` (nested
routines with `var` params, records, all statements, reals):
**0 false positives**. Broken mutants (12): **0 missed**, positions
close. (`i := 1` without `;` and unterminated comments are accepted
by `psc` too — separator/recovery leniency, correctly skipped.)