# Write-and-check demo

Shows the Nova128 workflow as far as it exists today: a program is typed
into the Vim clone on the C64, saved to disk, and checked on the C128 by
the compiler front end. No code is generated yet (epic E04), so nothing
runs.

```powershell
pwsh -File scripts/demo-write-check.ps1                  # good.n8 and bad.n8
pwsh -File scripts/demo-write-check.ps1 -Programs bad.n8
```

| File | Purpose |
|---|---|
| `good.n8` | Valid program: interface, class with private field, `init`, interface call |
| `bad.n8` | Four errors: `init` with a result, `destroy` with a parameter, private field used from the program, undeclared name |
| `n8check.s` | DEMO driver (not `N128C`): asks for a file name, runs source reader, lexer, names, and parser, shows diagnostics, writes `NAME.ERR` |

The script works on `build/demo/demo.d81`, a fresh copy of `vim/work.d81`
(the original is never written). x64sc and x128 run one after the other,
never together. Demo sources must be lowercase with no quotes or
backslashes, because they are typed through VICE's `-keybuf`.

Outputs in `build/demo/`: `NAME-vim.png` (the editor after `:w`),
`NAME-check.png` (the C128 screen), `NAME.seq` (the file Vim wrote), and
`NAME.err.txt` (the error file, when there are errors).