Organize related declarations with domain — Change one requirement

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

Rename a group without changing arithmetic meaning

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.

A pricing group is renamed from Shop to Pricing to clarify responsibility. Its helper body still computes price+fee. Sample change record: group label changes; local formula unchanged; (140,20) still predicts 160 cents; external naming impact = requires review under the actual module/export contract. This separates a local arithmetic invariant from possible caller integration changes.

Do not claim the rename is universally backward compatible. If public references depend on the old group name, they may need migration; this exercise does not establish that syntax. Equally, do not alter the formula just because the group’s label changed.

Worked reasoning and supplied artifact

// Worked contract artifact:
// A pricing group is renamed from Shop to Pricing to clarify responsibility. Its helper body still computes price+fee. Sample change record: group label changes; local formula unchanged; (140,20) still predicts 160 cents; external naming impact = requires review under the actual module/export contract. This separates a local arithmetic invariant from possible caller integration changes.

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 before/after responsibility maps and keep one identical arithmetic trace in both.

• 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.

Rename a materials group to Inventory while preserving its adjustment helper. Record unchanged paper behavior and the unresolved external-reference compatibility question.

What to produce

A rename record, same-input/same-result evidence and an explicit public-reference review item.

• 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.

• Rename a group without changing arithmetic meaning
• Create before/after responsibility maps and keep one identical arithmetic trace in both.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Create before/after responsibility maps and keep one identical arithmetic trace in both.

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