# TP3-comp — state summary

Recreating Turbo Pascal 3.0 (compiler / editor / shell) in GNU Modula-2
(`-fiso`), starting with the shell.

## Milestone: shell (TP3.0 main-menu shell)

Build: `cd shell && make`  (gm2 16.0.1, `-fiso`; output `shell/tpshell`)

### Files
- `shell/Term.def` / `shell/Term.mod` — raw termios keyboard + ANSI screen
  (ClrScr, GotoXY, Marked/Normal, blocking GetCh, Beep).
- `shell/Posix.def` / `shell/Posix.c` — `DEFINITION MODULE FOR "C"` bridge
  to libc: read/write/open/close/unlink/rename/getcwd/chdir/opendir/
  readdir/closedir/statvfs + termios (tcgetattr/tcsetattr/cfmakeraw).
- `shell/Shell.mod` — TP3.0 main-menu shell, same keys and layout as the
  original disassembled source (TPSRC4 kmenu / kcmdtab).
- `shell/Makefile` — builds via `make`. Note: gm2 only emits `main` when
  the program module source is on the link line
  (`gm2 -fiso -o tpshell Shell.mod Term.o Posix.o`).
- `RESUME-TP3.md` — full book-derived reference on the 8086 code the TP3
  compiler generates for each Pascal construct (source of the compiler
  phase design).
- `Resources/` — TCAT pdfs / OCR of "Au coeur de Turbo Pascal",
  TP3.0 reference manual, disassembled TPSRC1-10.

### Shell features (verified)
- Exact TP3.0 screen: `Logged drive`, `Active directory`, `Work file`,
  `Main file`, `Edit Compile Run Save` / `Dir Quit compiler Options`,
  `Text: n bytes`, `Free: n bytes`, `>` prompt. Command letters drawn
  bold (TP3 uses high-bit chars).
- Keys: L A W M E C R S D O Q; any other key redraws the menu (TP3).
- W — set work file, auto-`.PAS`, `Loading`/`New File`, append-on-save.
- S — save with `^Z` EOF; old file -> `.BAK` via unlink+rename (TP3 order).
- D — directory listing, DOS-style `*.*` mask glob, `No files`,
  `k bytes free` (statvfs).
- O — options submenu (M/C/H/O/D/I/A/P/F/Q) with on-screen state
  (compile target, Code/Data/Stack, command-line params).
- Q — confirmed quit (prompts to save when text changed).
- E / C / R — placeholders (editor, compiler, run to come).

### Reflection notes / quirks
- Model cannot view images (manual figures), so layout was reconstructed
  from the disassembled TPSRC source, which is authoritative for TP3.0.
- Foreign modules reject Modula-2-only types (`POINTER TO record`) —
  use `ADDRESS` and cast at the call site.
- gm2 ICEs on `FOR ... EXIT` loops (use `WHILE`+flag).
- termios is used in "raw" mode; output-affected: every newline is
  explicit `CR LF`.
- Directory glob implements DOS semantics: `*.*` matches everything,
  `*` matches runs, case-insensitive; skips `.`/`..`.

## Next steps
1. Editor: WordStar-style keys (^A..^Z basic editing, arrows, insert/overtype),
   reusing the `txt` text buffer already in Shell.mod.
2. Compiler: front-end + 8086 code generator per RESUME-TP3.md
   (program prologue with CS-prefixed typed constants, TU_STACK_CHECK
   parameter pushes, VAR parameter les/seg access, functions in AX /
   TU_RESU_FCT_ST strings, typed constants in code segment, absolute vars).
3. Interpreter ("R") for TP3 .COM-compatible execution.