Separate exposed API from capability permission — Flash-check repair

PART I

Warm-up

Reconnect with a useful idea before starting separate exposed api from capability permission. 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

Repair a visibility-as-permission assumption

An exposed API answers “which operation can the script name?” A capability answers “which resource may this caller use?” A native Willow programmer must not substitute process-level assumptions for the script host’s resource checks. Trace the requested operation, caller, resource and authorization independently; names such as navigator are exercise-host contracts, not builtins.

A design note says “navigator.open is public, so the mod may open staff-dashboard.” Sample diagnosis: valid fact = operation is visible; invalid inference = all targets authorized; corrected rule = host checks each target against caller capability. The source callback can remain as a request draft while its protected target must be approved or replaced by a permitted one.

Changing the word public to ulck does not justify the same inference. Exposure terms still concern the visible surface. Do not claim success by removing a permission check from the host design.

Worked reasoning and supplied artifact

// Worked contract artifact:
// A design note says “navigator.open is public, so the mod may open staff-dashboard.” Sample diagnosis: valid fact = operation is visible; invalid inference = all targets authorized; corrected rule = host checks each target against caller capability. The source callback can remain as a request draft while its protected target must be approved or replaced by a permitted one.

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

Rewrite the faulty inference as two independent facts and one required authorization check.

• 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: Safe extension design. Build a small, understandable change around separate exposed api from capability permission.

Repair a query design note asserting that import wdb authorizes all products. Keep the intended read narrow and provide an allowed subset plus denied collection case.

What to produce

A corrected permission explanation and concrete resource-scope matrix.

• 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.

• Repair a visibility-as-permission assumption
• Rewrite the faulty inference as two independent facts and one required authorization check.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Rewrite the faulty inference as two independent facts and one required authorization check.

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