Compose playback controls, device recovery contracts, and event cleanup — Connect the previous skills

PART I

Warm-up

Reconnect with a useful idea before starting compose playback controls, device recovery contracts, and event cleanup. 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.

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

PART II

Instruction & guided example

Connect device recovery to a closed panel

A device transition changes what an audio host can currently do, but does not define a universal recovery policy. Track device identity, user intent, position and owner. Resume, reload, restart and remain-paused are distinct decisions that must come from an explicit contract.

Preview owner P closes while voice V is paused for device loss. Reconnect arrives later. Host policy forbids restarting playback for closed owners; whether closing actively cancels native resources is a separate explicit host requirement.

Worked reasoning: Reconnect changes device availability only. The closed owner fails the resume guard, so no restart is requested. Resource cleanup still needs its own acknowledgement rather than being assumed from visible closure.

Failed alternative: Equating window close with proven native cancellation conflates an interface event with an unprovided cancellation guarantee.

Worked reasoning and supplied artifact

P open, V paused ->P closes ->owner closed
Device reconnect ->available
Resume eligibility:false(owner closed)
Cleanup status:requires documented native release evidence

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.

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.

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.

PART IV

Independent practice

Project context: Media operations console. Build a small, understandable change around compose playback controls, device recovery contracts, and event cleanup.

Analyze two panels P closed and Q open when a device returns. Keep each voices owner and eligibility separate.

What to produce

An owner/device/recovery matrix and unresolved cleanup evidence note.

• 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.

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.

import wdb;
domain Inventory {
    const lowStock = wdb.query({
        from: products,
        select: [id, name, stock],
        where: [[ stock < 10 ]],
        order: { by: stock, direction: ascending }
    });
}

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.

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.

• Connect device recovery to a closed panel
• Analyze two panels P closed and Q open when a device returns. Keep each voices owner and eligibility separate.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Require both current owner and current user intent before resuming.

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