[00143] Add the Rusty IvyML Markup Crate That Compiles Declarative Layout Into Widget Trees

[rorychatt]

00143 — Add the Rusty IvyML Markup Crate

Adds a fifth workspace crate, rusty-ivyml, exporting two function-like proc macros
that lower declarative XML-ish markup into the builder chains Rusty already has:

ivyml! {
    <Layout direction="vertical" gap=16 padding=24>
        <TextBlock content="Hello, World!" variant="heading1" />
        <Card>
            <TextBlock content={format!("count = {}", n)} />
            <Button title="Inc" on_click={move || count.update(|v| v + 1)} />
        </Card>
    </Layout>
}

ivyml_file!("src/views/dashboard.ivyml") does the same for external markup, resolved
against CARGO_MANIFEST_DIR and compiled at build time. No new runtime, no interpreter,
no wire-format change: a malformed tag is a rustc error with a span inside the markup,
not a panic in production.

Commits

Hash	What
f66d0a9	The rusty-ivyml crate (ast.rs, codegen.rs, lib.rs) plus workspace wiring and the rusty re-export
15882f9	rusty/tests/ivyml.rs — 10 tests
d22af2d	rusty-docs/docs/02_concepts/07_markup.md and the README crate row
3a34682	Merge origin/main (45dd7aa); resolve the members collision with rusty-desktop
67e4cd8	Inherited repair — rustfmt failure in rusty-macros/src/lib.rs
5d81694	Inherited repair — clippy::question_mark ×2 in rusty-macros/src/lib.rs
9fb4213	Inherited repair — widget_names scan blinded by #[derive(Widget)]

13 files, +1374 −35 against the merge-base.

Verifications

Gate	Result	Command actually run
RustFmt	Pass	cargo fmt --all -- --check
RustClippy	Pass	cargo clippy --workspace --all-targets --no-default-features -- -D warnings
RustBuild	Pass	cargo build --workspace --no-default-features
RustTest	Pass	cargo test --workspace --no-default-features — 498 passed, 0 failed
CheckResult	Pass	every deliverable enumerated; diagnostics and staleness guard exercised by hand
RustyFrontend{Lint,Build,Test}	Skipped	Rust-only change; git diff -- src/frontend/ e2e/ is empty

Every command was derived from node scripts/ci-step.js build <step> rather than from
the verification prompts, which still quote pre---no-default-features forms.

Design decisions worth knowing

Three came from prototype failures recorded in the plan, and all three are load-bearing:

1. &str slots get &(expr). Most constructors take &str, and the common case is
   content={format!(..)}, which is a String. Deref coercion handles it; requiring
   .as_str() in markup would be noise on every interpolating line.
2. on_* is checked before everything else and passed by value. Falling through to
   the &str default borrows the closure into a temporary that cannot satisfy the
   'static bound (E0716). Handlers are the reason the markup is worth having, so the
   naive ordering would not have compiled a single one.
3. ivyml_file! emits const _: &str = include_str!(..). A proc macro that reads a
   file has no dependency edge to it, and cargo:rerun-if-changed is build-script-only.
   Without this line cargo serves a stale expansion — silently, exit 0. I verified this
   in both directions rather than trusting the plan; see the four-run table in
   Verification/CheckResult.md. The line looks removable and is not.

Where I diverged from the plan, and why

1. Variant enums are addressed through their defining module. The plan's table
implies variant="ghost" lowers to rusty::widgets::ButtonVariant::Ghost.
widgets/mod.rs re-exports the widget structs but not the variant enums, so that path
does not resolve (E0432/E0433). Adding the re-exports would have meant editing
rusty/src/widgets/, which the plan's guardrail forbids and which would have collided
with plan 00093. So codegen.rs has a variant_module/enum_path pair emitting
::rusty::widgets::button::ButtonVariant instead. The documented markup surface is
unchanged. Re-checked against the post-merge tree: the enums are still not re-exported.

2. members also contains rusty-desktop. The plan quotes a four-crate members
line; rusty-desktop landed on main mid-execution at exactly the position this plan
edits. Resolved keeping both.

3. Modules are longer than the prototype (ast 203 vs 142, codegen 445 vs 303,
lib 119 vs 77). The growth is doc comments plus one real addition: parse_attr_name
uses syn::ext::IdentExt::parse_any so keyword attribute names (type, for) parse
rather than being rejected by Ident::parse.

4. Three inherited repairs, none of them this plan's code. All three landed via plan
00093's merge resolution 3d03c44 / commit 66128e0, after this plan's original base
6e7664c — which is why the PreExecution baseline was green. Each was proved inherited
before being touched: byte-identical blob to origin/main, empty
git log --not origin/main for the path, and reproduction in a detached probe worktree
at pristine origin/main with its own CARGO_TARGET_DIR.

I fixed rather than only filed them because cargo fmt --all, cargo clippy --workspace
and cargo test --workspace are whole-workspace gates: this plan could not report a
truthful Pass on the crate it adds while an unrelated crate was red. The third repair is
the substantive one — plan 00093 moved 12 widgets onto #[derive(Widget)], which
generates the "type": "..." literal that widget_names.rs was grepping for, so the
inventory fell 38 → 26 and button went missing. The scan now reads both declaration
styles, and two new controls stop the same blind spot reopening.

main is red right now on cargo test --workspace at e6c4398. 9fb4213 fixes it,
but only when this plan merges.

What is deliberately not here

• The other ~25 widgets. The ten shipped elements cover every structural shape the
  mapping needs — per-direction constructors, required-arg constructors, a non-child
  container method (List::item), and no-child leaves. The remainder is mechanical;
  filed as a recommendation, along with the three shapes that are genuinely not yet
  covered (Card/Dialog footers, Tooltip's single boxed child, Field's positional
  Element constructor).
• trybuild coverage of the nine diagnostics. Needs a new dev-dependency; filed.
  All nine were exercised by hand and produce the documented text with token-accurate
  spans.
• ivyml/ivyml_file in rusty::prelude. Guardrail: a glob-imported ivyml! reads
  as a locally defined macro, and the prelude exports only types.

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Commits:

• 9fb4213 [00143] Teach the widget_names scan to see derive-generated wire names
• 5d81694 Repair the inherited clippy failure in rusty-macros/src/lib.rs
• 67e4cd8 Repair the inherited rustfmt failure in rusty-macros/src/lib.rs
• 3a34682 [00143] Resolve merge conflicts with main
• d22af2d [00143] Document the markup layer
• 15882f9 [00143] Add the ivyml markup test suite
• f66d0a9 [00143] Add the rusty-ivyml crate with the ivyml! and ivyml_file! macros

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Created using Ivy Tendril.