Propose a host-neutral application contract — Boundary detective

PART I

Warm-up

Reconnect with a useful idea before starting propose a host-neutral application contract. 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

Make an empty-input outcome different from unavailable data

A host-neutral application contract describes user goals, supplied data, services, permissions, lifetime and evidence before choosing environment-specific integrations. The source’s Application constructor and app.ready callback are illustrative host inputs, not builtins supplied by this school. A Willow learner can reuse precise state reasoning while keeping proposed .ws and conceptual native services distinct from implemented .w.

The planner’s kit list may genuinely be empty, or the inventory service may be unavailable. Sample outcome table: successful empty list → tell the organizer no kit items are currently listed; unavailable service → explain data could not be obtained; denied read → safe refusal without protected details. The three states imply different next actions even if no item rows are shown.

Returning an empty list for every failure would turn uncertainty into a false data fact. Do not invent a query result union or error class to express the table; specify the distinction and ask for the supplied host result contract.

Worked reasoning and supplied artifact

// Worked contract artifact:
// The planner’s kit list may genuinely be empty, or the inventory service may be unavailable. Sample outcome table: successful empty list → tell the organizer no kit items are currently listed; unavailable service → explain data could not be obtained; denied read → safe refusal without protected details. The three states imply different next actions even if no item rows are shown.

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

Write all three states with an appropriate user goal and the evidence that would distinguish them.

• 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: Independent WillowScript application. Build a small, understandable change around propose a host-neutral application contract.

Design empty, unavailable and denied outcomes for a tournament schedule viewer. Include a successful-empty sample input and two different host-failure conditions.

What to produce

A three-state outcome contract and required host evidence, with no empty-result laundering.

• 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 wuix.widget;
import app;
domain Workspace {
    const application = Application({
        name: "Workspace",
        window: { title: "Dashboard", size: [1280, 800] },
        events: {
            "app.ready": fnc() -> void { console.log("Ready"); }
        }
    });
}

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.

• Make an empty-input outcome different from unavailable data
• Write all three states with an appropriate user goal and the evidence that would distinguish them.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Write all three states with an appropriate user goal and the evidence that would distinguish them.

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