Element IDs

Give controls stable names so DayScript can find them in any UI language. Declare each identity at the piece with id!.

button(res::str::save()).id(id!(account::save))
label(state).id(id!(camera_state))
row(content).id_of(move || id!(query_row, slot.item().key()))

fn readout(text: impl Fn() -> String + 'static, id: ElementId) -> impl Piece {
    label(text).tabular().id(id)
}
readout(value, id!(volume_value))

The macro is exported through day, day-pieces, day-core, and the usual preludes. Each segment uses lowercase ASCII Rust-style names: no keywords, raw identifiers, leading or trailing underscores, doubled underscores, or case conversion. Namespaces are written with ::. These tokens are declarations, not references to generated Rust symbols: IDE symbol rename/completion does not manage a vocabulary. Rename source and script references together.

ElementId is Clone. A reusable Fn closure must clone a captured ID if it gives the value to a builder on each call. Element setters and builders take the typed value; arbitrary strings cannot be converted into IDs.

Keys and composite controls

IntoElementKey accepts integer and string values, and explicit application implementations. It does not accept arbitrary Display values. A custom key must have a stable, unambiguous canonical text representation. The macro evaluates the key expression once.

.id(id!(query_row, 42_u64))         // query_row:42
.id(id!(account::row, ":a b"))    // account::row:%3Aa%20b

Only key bytes are escaped: UTF-8 outside A-Z a-z 0-9 - . _ ~ uses uppercase percent encoding. Integer 42 and text “42” are the same key. Empty keys are allowed (row:). Scripts retain scalar locators; no tagged object schema is required:

- tap: { id: 'query_row:42' }
- assert_text: { id: camera_state, key: camera_running }

Retain .id_of for recycled rows. A one-time .id would keep identifying the old item after rebinding. A tree’s .row_id also takes a closure returning ElementId; its canonical string is used in expand.row and tree_move.row/parent references.

Composite controls declare their distinct targets explicitly:

rating(stars)
    .star_id(|n| id!(rating_star, n))
    .id(id!(rating_row))
legend(entries).entry_id(|key| id!(series_legend, key))

Framework-owned settings children use declared families such as pref:<preference-key>, pref_increment:<encoded-control-id>, prefs_group:<group-key> and about_link:<index>. Document strips accept .strip_id(id!(documents)); library-owned tab, close and new buttons use document_tab, document_close, and document_new families with encoded host/row keys. Route, model, and preference keys are separate from element IDs.

Validation and accessibility

A family must have the same owner and static or keyed shape throughout the app. Use namespaces to avoid collisions between packages. Conflicts fail before a walkthrough runs. day lint checks source declarations, but does not expand custom macros or evaluate Cargo features. The compiled app validates the declarations used on the selected target.

IDs identify controls in Day’s tree, accessibility tree, and DOM. They do not replace localized accessibility labels. See accessibility. .id names the piece independently of wrapper order. Document tabs also offer .wrapper_id to name the current wrapper.

Reports and gates

A scripted launch validates every target-applicable element reference before its first step. An unknown or wrongly shaped reference is an error even for an absence assertion; remove obsolete tests for IDs which no longer exist rather than declaring them in a driver.

Enable family-level coverage in the app’s Day.toml:

[dayscript.coverage]
enabled = true
# Add a minimum after reviewing a complete suite's baseline:
minimum = 80

[dayscript.coverage.targets.ios-uikit]
minimum = 75

[[dayscript.coverage.exclusions]]
id = "camera_title"
targets = ["ios-uikit"]
reason = "This target uses the native navigation heading."

Setting a minimum also enables reporting and the gate, even without enabled = true.

The example exclusion is only appropriate when that app actually has that declaration and behavior. Unknown exclusions and empty reasons fail. Coverage reports are saved alongside existing dayscript reports under build/day/reports/dayscript. They retain the compiled catalog, operation outcomes, family-only evidence, cumulative mounted families, and uncovered families, plus never-mounted and mounted-but-unexercised diagnostics when a mount snapshot is available. Reports are saved as JSON; the CLI prints the suite score.

The primary score is |interacted ∪ asserted| / eligible declared families. Repeated keys, actions and retries do not multiply credit. Waits are observed-only; negative assertions and screenshots earn no exercised credit. Failed steps and optional absent actions earn none. A named label can be exercised by a positive assertion. Unnamed controls, all possible key values, visual fidelity, and business correctness are not measured. Treat this as element-ID coverage, not total UI coverage. Some operations without an explicit locator (for example, a menu command selected only by localized label) conservatively receive no family credit.

Launch multiple scripts together to gate their union. Reports from one target/profile and one launch session can also be checked later with an explicit suite manifest:

{
  "schema_version": 1,
  "target": "web-dom",
  "reports": {
    "dayscript/demo.yaml": "reports/demo-final.json",
    "dayscript/settings.yaml": "reports/settings-final.json"
  },
  "policy": { "minimum": 80 }
}

day coverage check --manifest suite.json

Paths are manifest-relative. The command fails on missing, failed, incomplete, duplicate, retried, or mixed-session/target/profile reports. It never globs an output directory. Aggregation requires one launch session; reports from independent launches cannot be combined. Separate targets always have separate gates. A zero denominator is not 100%, and an enabled minimum fails for zero eligible declarations. Percentages are compared using counts, without rounding to the displayed score. Test failure always fails the invocation independently of coverage.