# F-Breakpoint — `breakpoint` command (+2)

**Suite:** `hs-upstream-breakpoint`  
**Target:** Both tests are `SKIP (untranslated)`.

## 1. The 2 tests

- `parses as a top-level command`
- `parses inside an event handler`

Both are untranslated — no test body exists. The test names say "parses" — these are parser tests, not runtime tests.

## 2. What upstream checks

From `test/core/breakpoint.js`:

```js
it('parses as a top-level command', () => {
  expect(() => _hyperscript.evaluate("breakpoint")).not.toThrow();
});
it('parses inside an event handler', () => {
  const el = document.createElement('div');
  el.setAttribute('_', 'on click breakpoint');
  expect(() => _hyperscript.processNode(el)).not.toThrow();
});
```

Both tests verify that `breakpoint` is accepted by the parser without throwing. Neither test checks that the debugger actually fires. `breakpoint` is a no-op command in production builds — it calls `debugger` in JS, which is a no-op when devtools are closed.

## 3. What's needed

### Parser (`lib/hyperscript/parser.sx`)

Add `breakpoint` to the command dispatch — it should parse as a zero-argument command. The parser's command `cond` (wherever `add`, `remove`, `hide` etc. are dispatched) needs a branch:

```
((= val "breakpoint") (hs-parse-breakpoint))
```

`hs-parse-breakpoint` just returns a `{:cmd "breakpoint"}` AST node (or however commands are represented). It consumes no additional tokens.

### Compiler (`lib/hyperscript/compiler.sx`)

Add a compiler branch for `breakpoint` AST node. Emits a no-op or a `debugger` statement equivalent. Since we're in SX (not JS), a no-op `(do nil)` is correct.

### Generator (`tests/playwright/generate-sx-tests.py`)

The 2 tests are simple — hand-write them:

```lisp
(deftest "parses as a top-level command"
  (let ((result (guard (e (true false))
                  (hs-compile "breakpoint")
                  true)))
    (assert result)))

(deftest "parses inside an event handler"
  (hs-cleanup!)
  (let ((el (dom-create-element "div")))
    (dom-set-attr el "_" "on click breakpoint")
    (let ((result (guard (e (true false))
                    (hs-activate! el)
                    true)))
      (assert result))))
```

## 4. Implementation checklist

1. `sx_find_all` in `lib/hyperscript/parser.sx` for the command dispatch `cond`.
2. Add `breakpoint` branch → `hs-parse-breakpoint` function returning minimal command node.
3. `sx_find_all` in `lib/hyperscript/compiler.sx` for command compilation dispatch.
4. Add `breakpoint` branch → emit no-op.
5. Replace 2 `SKIP` bodies in `spec/tests/test-hyperscript-behavioral.sx` with translated tests above.
6. Run `hs_test_run suite="hs-upstream-breakpoint"` — expect 2/2.
7. Run smoke 0–195 — no regressions.
8. Commit: `HS: breakpoint command — parser + no-op compiler (+2)`

## 5. Risk

Very low. Zero-argument no-op command. The only risk is mis-locating the command dispatch branch in the parser.