Select fields without assuming hidden imports — Change one requirement

PART I

Warm-up

Reconnect with a useful idea before starting select fields without assuming hidden 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

Adapt a nullable native field

For a W developer moving into proposed WS, translate the intended data operation rather than native storage mechanics. The query DSL, object literals and bound-expression forms are proposed extensions. Collections and field names are explicit exercise-host inputs; importing a service neither supplies those resources nor grants access.

Supplied bridge fixture: Native name may be absent; the proposed public result requires a display name. Row has id r1,stock2,name absent.

The adapter cannot truthfully promise a required name without a defined reject/default policy. An explicit fallback such as Unnamed item is a host decision and must remain distinguishable from source data if that matters. Do not infer WS nullable semantics from native representation.

Record the request, intermediate decisions and final artifact separately. These are paper derivations and platform-contract exercises; .ws and its native services are not implemented or executed by this school. Shared fnc/domain/import vocabulary does not certify parser support for proposed extensions or prove runtime security enforcement.

Worked reasoning and supplied artifact

// PAPER FIXTURE — Adapt a nullable native field
// Manual worked artifact; comments below are not executable source.
// INPUT / CONTRACT: Supplied bridge fixture: Native name may be absent; the proposed public result requires
// a display name. Row has id r1,stock2,name absent.
// DERIVATION / EXPECTED ARTIFACT: The adapter cannot truthfully promise a required name without a defined
// reject/default policy. An explicit fallback such as Unnamed item is a host decision and must remain
// distinguishable from source data if that matters. Do not infer WS nullable semantics from native
// representation.

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

Guided exercise: reproduce this exact fixture, annotate each native-versus-script responsibility, then explain why the rejected answer “A promise that absent always means empty text” fails.

• 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: Inventory review workspace. Build a small, understandable change around select fields without assuming hidden imports.

Specify reject-row and labeled-fallback contracts and trace two fixture rows through each. Supply different fixture identities/values from the worked case, a complete predicted result or allow/deny artifact, a stepwise trace, one contrasting failure and the required host contract.

What to produce

Specify reject-row and labeled-fallback contracts and trace two fixture rows through each. Preserve source/implementation status and separate manual predictions from future toolchain evidence.

• 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.

• Adapt a nullable native field
• Native name may be absent; the proposed public result requires a display name. Row has id r1,stock2,name absent.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Change one field,resource scope,lifetime or input value in the bridge fixture. State the new intermediate decisions and final result without assuming a running WS host.

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