Review public API boundaries, locked exposure, and transitive imports — Connect the previous skills

PART I

Warm-up

Reconnect with a useful idea before starting review public api boundaries, locked exposure, and transitive imports. 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 policy to diagnostic messages

The source names lck/ulck exposure policy, but a lesson must not invent an executable policy format or assume visibility equals permission. Use explicit plain tables to reason about which surface the host exposes, then carry resource-specific capability checks into every visible operation.

Exercise policy table: Viewer profile exposes catalog.listTitles; Maintainer profile additionally exposes maintenance.rebuild. Both profiles remain limited to project P. Project Q is outside their grant scope. The profile labels and table are exercise-host documentation; exact lck/ulck configuration syntax must come from an authoritative host contract.

Supplied case: Viewer requests hidden maintenance; Maintainer requests out-of-scope Q. External messages must not reveal protected project content.

Worked reasoning: These failures have different internal reasons but both need safe visible responses. Keep rich diagnostic categories in an authorized review channel, while user-facing text explains the unavailable operation without exposing Q’s data.

Contrast and diagnosis: Detailed errors are not automatically harmless just because the operation was denied.

Worked reasoning and supplied artifact

// Disposable exercise fixture / host-contract notes; not executable API syntax.
// Supplied input: Viewer requests hidden maintenance; Maintainer requests out-of-scope Q. External messages must not reveal protected project content.
// Worked prediction: These failures have different internal reasons but both need safe visible responses. Keep rich diagnostic categories in an authorized review channel, while user-facing text explains the unavailable operation without exposing Q’s data.
// Rejected alternative: Detailed errors are not automatically harmless just because the operation was denied.

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: Approved API inventory. Build a small, understandable change around review public api boundaries, locked exposure, and transitive imports.

Write external and internal messages for hidden API, missing project and out-of-scope project cases. Identify which facts each audience may know.

What to produce

Write external and internal messages for hidden API, missing project and out-of-scope project cases. Identify which facts each audience may know. 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 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 policy to diagnostic messages
• 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 “Connect policy to diagnostic messages” 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.