max / quasi

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1	//! A staged include of a constant shape is evaluated where it stands.
2	//!
3	//! The boundary this is about: `symbolic::stage` gives a twin one parameter,
4	//! the plan, and a staged `include` drops the caller's arguments. So a shape
5	//! reached through an include put a sentinel where its own parameter was,
6	//! however literal the caller's argument was, and the real call happened per
7	//! request through the filler. `#[constant]` is the promise that lets the call
8	//! be made once instead (quasicoherent `793d99dd`).
9
10	use quasi_declare::declare;
11	use quasi_router::stage::Plan;
12
13	declare! {
14	/// A shape whose answer is decided entirely by what it is handed.
15	#[constant]
16	pub shape label(text: &str) -> Node;
17
18	text text;
19	}
20
21	declare! {
22	/// The caller, which reaches `label` with a literal.
23	#[staged]
24	pub shape panel() -> Node;
25
26	region "panel" as Pane {
27	include label("written down");
28	}
29	}
30
31	#[test]
32	fn a_constant_include_of_a_literal_lands_in_the_staged_twin() {
33	// The twin is what a residual is derived from, so what it holds is what
34	// gets baked in. The words being there mean the call was made while
35	// staging; a sentinel there would mean it was deferred to a request.
36	let rendered = format!("{:?}", panel_staged(&Plan::full(1)));
37
38	assert!(
39	rendered.contains("written down"),
40	"the literal did not survive the include boundary: {rendered}"
41	);
42	assert!(
43	!rendered.contains("ZQH"),
44	"a sentinel stood in for a value nothing varies: {rendered}"
45	);
46	}
47
48	#[test]
49	fn the_promise_leaves_the_shape_itself_alone() {
50	// The shim is the shape under a second name and nothing else, so the two
51	// cannot answer differently.
52	assert_eq!(label("same"), label_constant("same"));
53	}
54
55	#[test]
56	fn a_staged_shape_answers_for_nothing_when_every_include_is_constant() {
57	// No scope was opened, so the plan has nothing to enter and the shape's
58	// counts say so. A site here would be a residual carrying a gap that no
59	// request ever fills.
60	assert_eq!(PANEL_STAGED.sites, 0);
61	assert_eq!(PANEL_STAGED.holes, 0);
62	}
63