Explain, improve, and resubmit — Boundary detective

PART I

Warm-up

Reconnect with a useful idea before starting explain, improve, and resubmit. 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

Choose the regression case that catches the repair

Revision should change the evidence behind a claim. Explain a project through its contracts and traces, then revise one identified gap at a time. A stronger submission is not merely longer: it closes an ambiguity, repairs a wrong transition or adds a discriminating case. The public path uses self-check and personal progress, with no private exam keys or execution grades.

A bug let an observer submit through a direct callback path despite a disabled button. The repair adds a current-grant check at the operation boundary. Happy-path editor submission already worked.

Compare the old and new claim against exactly the same supplied case. Record what changed, why it matters and what remains unknown. Preserve correct work and stable lesson progress while improving the artifact; never relabel an untested design as a verified native program. Worked case: The decisive regression is an observer invoking the submission path directly: expect denial and zero queue effect. Also preserve the editor’s allowed path. A screenshot of the disabled button would pass both the broken and repaired versions.

Compare the tempting alternative: Testing only the already-working editor path cannot show that the new boundary check solved the reported defect.

Worked reasoning and supplied artifact

// Paper trace / supplied exercise-host contract; no execution claimed.
// A bug let an observer submit through a direct callback path despite a disabled button. The repair adds a current-grant check at the operation boundary. Happy-path editor submission already worked.
// The decisive regression is an observer invoking the submission path directly: expect denial and zero queue effect. Also preserve the editor’s allowed path. A screenshot of the disabled button would pass both the broken and repaired versions.

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: Event-driven team utility. Build a small, understandable change around explain, improve, and resubmit.

Write preconditions, invocation, expected decision and effect count for the denied direct call, then an allowed editor control case.

What to produce

A focused two-case regression specification with zero/one effect expectations.

• 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.

• Choose the regression case that catches the repair
• Write preconditions, invocation, expected decision and effect count for the denied direct call, then an allowed editor control case.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Write the expected number of queue operations for the observer case.

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