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 empty results to truthful display

A reviewable API inventory links the proposed feature to every host action it requires. Use realistic data fixtures to reveal which fields and resources are actually needed. Keep public names, requested operations, grants, unavailable-service behavior and evidence status together.

Exercise feature: a low-stock screen for collection PublicProducts, approved fields id/name/stock, filter stock < 10 and ascending stock order. Fixture: A Arrow stock 0; B Bow stock 9; C Cape stock 10. WDB query syntax and WUIX are proposed conceptual services; products and query-field names require an explicit host binding.

Supplied case: Approved query returns no rows because all stocks are 10 or more. Separate failure case: collection cannot be read.

Worked reasoning: A successful empty result means no row matched the rule. An unavailable read means the result is unknown. Display “no low-stock items” only for the successful empty query; show an unavailable status for the failed read.

Contrast and diagnosis: Conflating errors with empty results gives the user false confidence that inventory needs no attention.

Worked reasoning and supplied artifact

// Disposable exercise fixture / host-contract notes; not executable API syntax.
// Supplied input: Approved query returns no rows because all stocks are 10 or more. Separate failure case: collection cannot be read.
// Worked prediction: A successful empty result means no row matched the rule. An unavailable read means the result is unknown. Display “no low-stock items” only for the successful empty query; show an unavailable status for the failed read.
// Rejected alternative: Conflating errors with empty results gives the user false confidence that inventory needs no attention.

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.

Design two visible states and evidence records for empty-success versus read-unavailable, retaining the same filter rule.

What to produce

Design two visible states and evidence records for empty-success versus read-unavailable, retaining the same filter rule. 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 empty results to truthful display
• 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 empty results to truthful display” 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.