Organize related declarations with domain — Review and demonstrate

PART I

Warm-up

Reconnect with a useful idea before starting organize related declarations with domain. 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

Review a domain design with a public-surface inventory

A domain groups related declarations in the shown language design. For an experienced Willow learner, use it to make responsibility boundaries readable, while avoiding assumptions about instance creation, automatic public exposure or how an external caller qualifies a name. Exact module/export behavior still needs its documented contract.

The sample final inventory has Pricing.total for price-plus-fee, Inventory.remaining for capacity-minus-used, local source bodies, intended caller roles and pending external lookup/exposure rules. It includes traces (200,25)→225 cents and (12,5)→7 parts. A reviewer can inspect organization and arithmetic while seeing exactly which module-system facts are not provided.

Do not mark every grouped declaration public by default. A domain name is not an authorization decision, and a correct paper case is not a compiler acceptance result. This bridge ends with an interface review artifact, not a native deployment.

Worked reasoning and supplied artifact

// Worked contract artifact:
// The sample final inventory has Pricing.total for price-plus-fee, Inventory.remaining for capacity-minus-used, local source bodies, intended caller roles and pending external lookup/exposure rules. It includes traces (200,25)→225 cents and (12,5)→7 parts. A reviewer can inspect organization and arithmetic while seeing exactly which module-system facts are not provided.

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

Create the inventory and classify its fields as source facts, design intentions or unresolved integration requirements.

• 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: Shared pricing rules. Build a small, understandable change around organize related declarations with domain.

Submit two grouped mod rules with purpose, units, sample cases and a proposed minimal public surface. State which exposure/qualification details must be checked against the actual host design.

What to produce

A responsibility/public-surface table, source drafts, paper traces and honest unresolved semantics.

• 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.

fnc add(a: i32, b: i32) -> i32 {
    return a + b;
}
fnc main() -> i32 {
    return add(2, 3);
}

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.

• Review a domain design with a public-surface inventory
• Create the inventory and classify its fields as source facts, design intentions or unresolved integration requirements.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Create the inventory and classify its fields as source facts, design intentions or unresolved integration requirements.

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