# Pascal corpus census

`Sources/Dezip/` is an external collection, not part of the build.  It contains
**4,919 `.pas` files** (77 MB, about 354k lines).  Most are SWAG/FreePascal or
Delphi units, so a failure count is not a compiler score; it is a map of what
the TP3 subset does not cover yet.

## Method

Every file was compiled separately with the current `shell/compiletest`, in a
fresh process and with a 5-second timeout.  Separate processes matter: the
first batch run aborted after a compiler bug, and one crashing source must not
hide the rest of the corpus.

## Current result

| result | count |
|---|---:|
| compiles | **49** |
| errors | **4,870** |
| crashes/timeouts | **0** |

By error code:

| code | meaning | count |
|---|---|---:|
| 41 | unknown construct/identifier | 4,335 |
| 90 | include file not found | 418 |
| 102 | not implemented | 48 |
| 1 | syntax / semicolon | 39 |
| 30 | simple type expected | 20 |
| 56 | type mismatch | 9 |
| 99 | compiler overflow | 1 |

The useful subset is `pascsrc/`, which is the classic TP3 example material:
**44 of 84 compile**.  The SWAG tree is 4,473 files, almost all FreePascal or
Delphi units; only 5 compile.

## Bugs found by the corpus

- **Typed constants containing an array of strings crashed the compiler.**
  A one-character element such as `'I'` is scanned as a `CHAR` scalar, not a
  string, so `DefConst` took the integer path and shifted a 16-bit value through
  `divi` until it became zero: `SIGFPE` in `DefConst`.  The array element type
  is now consulted; a scalar element of a `STRING` array is stored as a
  one-character string.  `t118_strconstarray` compiles and prints `''`, `I`,
  `II`.
- This bug was also hit by `Roman2.pas` in the SWAG tree.  It now gets a normal
  diagnostic (`Word` is not yet a type) instead of killing the compiler.

## Main blockers visible in the census

1. `uses`/`unit` imports.  Most SWAG files cannot even reach a declaration
   after their `uses` line.
2. The wider integer family: `Word`, `LongInt`, `ShortInt`, `Single`, `Double`.
3. Turbo extras such as `absolute`, `Printer`, `Dos`, `Mem`/`Msdos`, and
   `Addr` beyond the currently supported pointer paths.
4. Includes whose names or search paths differ from the file's own directory
   (`ERROR 90`, 418 files).

The 49 clean files are useful smoke material, but the corpus is intentionally
not wired into `run_all.sh`: it lives outside the repository and most of it is
outside the TP3 language subset.

## Conservative cleanup

The obvious non-TP3 material was removed:

- the whole `Dezip/swag-pascal-master` tree and its
  `swag-pascal-master.zip`;
- 416 `.pas` files outside that tree that declare `unit`, use `uses`, or carry
  FreePascal/Delphi markers;
- 42 zip archives whose Pascal entries were **all** marked in that way.

Mixed archives — including `pascsrc.zip`, which also contains the 44 compiling
TP3 examples — were deliberately kept.

Before cleanup: **6,810 files**, **4,919 `.pas`**, **907 zips**.
After cleanup: **1,731 files**, **71 `.pas`**, **858 zips**.

The remaining 71 Pascal files compile as **54 OK / 17 errors** after the first
compiler upgrades (long identifiers, named labels, `Addr`, field widths,
nested arrays, negative bounds, forward pointer types, `NIL`, and forward
procedure parameters).  The remaining 17 are TP3-feature gaps, not
unit/Delphi noise.