Use validated handles instead of raw pointers — Discover and trace

PART I

Warm-up

Reconnect with a useful idea before starting use validated handles instead of raw pointers. 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

Trace the permitted resize request

An automation extension should request narrowly authorized host operations on validated resources. A token is an opaque reference with identity and lifetime, not a native address. Validate the operation at the host boundary even when the caller supplies a familiar-looking identifier.

Exercise host offers image resize on approved asset A for mod M. Handle a9 maps to A, generation 2, owner M, read/resize only. Asset B belongs to another mod. The source does not define token encoding or resize API signatures; these fixtures are plain request/decision records.

Supplied case: M presents a9 for resize of A generation 2 to width 320.

Worked reasoning: Validate the token mapping, current generation, caller scope and allowed operation. All agree in this fixture, so the proposed resize may proceed under its size budget. The token does not authorize deleting A or reading B.

Contrast and diagnosis: A valid handle establishes only its documented operations and scope.

Worked reasoning and supplied artifact

// Disposable exercise fixture / host-contract notes; not executable API syntax.
// Supplied input: M presents a9 for resize of A generation 2 to width 320.
// Worked prediction: Validate the token mapping, current generation, caller scope and allowed operation. All agree in this fixture, so the proposed resize may proceed under its size budget. The token does not authorize deleting A or reading B.
// Rejected alternative: A valid handle establishes only its documented operations and scope.

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: Restricted automation extension. Build a small, understandable change around use validated handles instead of raw pointers.

Write request records for resize A and delete A using the same token; identify the extra operation check.

What to produce

Write request records for resize A and delete A using the same token; identify the extra operation check. Include input → intermediate decision/state → predicted outcome, with any required host rule stated explicitly.

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

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.

• Trace the permitted resize request
• Explain the decision for the supplied case, then independently work the changed fixture.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

In one or two sentences, name the decisive rule in “Trace the permitted resize request” and predict the outcome of one changed input from your independent fixture. State which host behavior still needs real verification.

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