Model ordered lists, nested settings, and typed event configuration — Discover and trace

PART I

Warm-up

Reconnect with a useful idea before starting model ordered lists, nested settings, and typed event configuration. In one or two sentences, describe the input, output or host boundary from the previous exercise that this lesson builds on. If you are arriving directly, skim the worked example first; there is no locked prerequisite.

Recall note

A rough note is enough. You can revise it after the example.

PART II

Instruction & guided example

Trace registration and a typed delivery separately

Typed event configuration must connect a declared callback contract to the actual delivery shape. Registration stores a response; delivery supplies inputs later. Shared fnc vocabulary does not make Event, navigator or an arbitrary event field a builtin. Treat every such name as an explicit exercise-host dependency.

Exercise host declares Event={itemId: i32} and invokes a callback fnc(event: Event)->void on selection. At registration selectedId=none. Later it delivers itemId42. The event type is a supplied contract, not a builtin.

Worked reasoning: Registration stores the callable without selecting an item. Delivery binds event.itemId42, and the response may request details for42 under a separate capability check. The payload value is not available earlier.

Failed alternative: Reading event.itemId during configuration creation uses a delivery-time parameter before any invocation exists.

Worked reasoning and supplied artifact

// Proposed callback value; Event supplied by host
fnc(event: Event) -> void {
    // Request details for the supplied event.itemId under host permission.
}
// register:selected none;deliver itemId42:request42

Illustrative example from the proposed WillowScript design. The language and WUIX/WMATH/WDB/WAUDIO/WTMP services are not implemented in the supplied source. This site has no interpreter, VM or native host and does not execute or certify the snippet.

Walk through the example, one line at a time

// Proposed callback value; Event supplied by host
This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
fnc(event: Event) -> void {
This configuration value is a callback. Registration describes a response; the host contract determines when and with which context it is called.
// Request details for the supplied event.itemId under host permission.
This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
}
Close the nested block or value begun earlier. Match it to its opening boundary to keep the structure readable.
// register:selected none;deliver itemId42:request42
This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.

Try the guided change

Reconstruct the supplied worked case first: list its inputs, intermediate decisions and final artifact. Compare each row with the explanation and identify exactly where the rejected alternative fails. Then use the changed inputs in Part IV for independent work.

Write the supplied inputs and initial state before following the example.
Reconstruct each intermediate calculation or host decision, then compare with the worked artifact.
Explain why the contrasting alternative fails before attempting the changed inputs in Part IV.

Prediction or guided notes

PART III

Take a breather

Step back after the guided example. Look away from the screen, stretch, or reread your prediction. This is an optional learning pause, not a timer or an assessment gate.

When you return, try to name the lesson’s key idea without copying its wording. If that feels difficult, return to Part II and trace one line rather than restarting the entire lesson.

Your drafts remain here. Continue whenever you are ready.

PART IV

Independent practice

Project context: Reusable configuration workspace. Build a small, understandable change around model ordered lists, nested settings, and typed event configuration.

Trace registration followed by a delivery itemId7 and a later delivery itemId19. Keep each invocation input distinct.

What to produce

A registration/invocation/payload ledger with explicit Event schema.

State the intended behavior in a sentence before editing.
Use only source-backed syntax and the host services whose contract you have been given.
Record a normal case and a boundary or unavailable-resource case.
Label hand predictions separately from anything actually measured in a supplied toolchain.

Your .ws practice draft

Syntax colors are a reading aid, not a compiler. The line you are editing stays uncolored until you move to a different line; capitalization is never changed. Drafts stay on this browser and code is not executed.

Need a hint?

The declared host invocation provides the parameter; registration stores the callable but supplies no payload.

Reading event.itemId during configuration creation uses a delivery-time parameter before any invocation exists.

Original learning-path task and reference

In a rhythm-game audio editor, demonstrate model ordered lists, nested settings, and typed event configuration. Read the source-grounded example and predict its observable behavior before making changes. Include .ws source and a host-resource contract; compare at least one normal case and one edge case.

import wuix.widget;
const button = widget.Button({
    text: "Continue",
    events: {
        click: fnc() -> void {
            navigator.open("dashboard");
        }
    }
});

Where the original task needs a host API that is not supplied here, write the contract and predictions. Do not invent a runtime result.

PART V

Self-check

Use this check to notice what to revisit. It does not award a private course grade, block another page or claim to verify compiled code. Every answer has a learning explanation.

When is itemId42 supplied?At callback deliveryAt import timeWhenever Event is spelled

Explain a normal or boundary case

You may keep exploring even if you are unsure. Use the hint, compare the trace, and revise your explanation.

PART VI

Recap & small task

Bring the idea back to the mod feature you are building. A useful recap connects the mechanism to a decision you can make in your own code.

Trace registration and a typed delivery separately
Trace registration followed by a delivery itemId7 and a later delivery itemId19. Keep each invocation input distinct.
Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Separate configuration-time state from invocation-time input.

Your recap

This marks your personal practice record only. It is not a certification or an official workspace assessment.