# Turbo Pascal 3 validator pilot

`turbo_pascal3.atg` is byte-identical to the standard-Pascal grammar
apart from its tag line, so it starts from the same base plus three
Turbo extensions (all diagnosed against `fpc -Mtp` as oracle):

1. `IGNORE CASE` moved right after `COMPILER` (same toolchain
   requirement as the standard grammar).
2. `$` hexadecimal literals (`$FF`): new `hexDigit` set plus a
   `"$" hexDigit { hexDigit }` integer alternative.
3. `ELSE` in `CASE`: `CaseList` gains `[ "ELSE" Statement ]`
   (standard Pascal has none; Turbo and `fpc -Mtp` accept it).

Two benign LL(1) warnings remain (dangling-`ELSE` family).

## Build

```sh
./build.sh        # -> build/TP3 (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`). Note: link via
the two-step module list (`-fgen-module-list` then `-fuse-list`); a
single-step link trips over pre-existing errors in this gm2 build's
own ISO library `.def` files.

## Differential results (TP3 vs `fpc -Mtp`)

Accept battery + `tests/deep.pas` (adds `STRING`, `+` concat, `$`
hex, `CASE..ELSE` over the standard set): **0 false positives**.
Broken mutants: **0 missed**, positions close.