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 the domain boundary with a change request

A domain groups related declarations under a meaningful boundary. The shared domain vocabulary expresses organization. Group declarations because they share a coherent responsibility and contract, not because they happen to be called from the same screen. A namespace is not automatically a resource permission boundary, an ownership transfer or a runtime isolation guarantee.

A reviewer requests a new rounding display style without changing stored numeric totals. Current design mixes number calculation and formatted labels in Pricing. Example exact total is 12.5; display style may show 12.50.

Draw the declarations and their dependencies. Follow one call across a domain boundary and write the input and result contract on that edge. If two domains depend on each other, inspect whether a shared rule or an explicit orchestration layer would make the direction understandable. Worked case: Keep the numeric result contract stable and move or separate presentation formatting. Stored 12.5 and label 12.50 represent different artifacts. A formatting change should not silently change the durable value.

Compare the tempting alternative: Converting every result to a formatted string inside the core rule changes its result type and can break numeric callers that never needed a label.

Worked reasoning and supplied artifact

// Paper trace / supplied exercise-host contract; no execution claimed.
// A reviewer requests a new rounding display style without changing stored numeric totals. Current design mixes number calculation and formatted labels in Pricing. Example exact total is 12.5; display style may show 12.50.
// Keep the numeric result contract stable and move or separate presentation formatting. Stored 12.5 and label 12.50 represent different artifacts. A formatting change should not silently change the durable value.

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

Propose a boundary revision and compare numeric consumer, display consumer and stored-record behavior before and after the change.

What to produce

A three-consumer impact table and an unchanged-numeric-value postcondition.

• 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 the domain boundary with a change request
• Propose a boundary revision and compare numeric consumer, display consumer and stored-record behavior before and after the change.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Write one numeric artifact and one presentation artifact separately.

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