Import only the public APIs you use — Build the smallest useful slice

PART I

Warm-up

Reconnect with a useful idea before starting import only the public apis you use. 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

Keep a pure pricing helper free of unnecessary imports

An import requests a named public API from the proposed library hierarchy. A narrow import is not evidence that sibling modules are visible, that native services are installed or that a capability is granted. Existing Willow module experience helps you ask precise questions, but it cannot fill missing WillowScript host contracts.

A price+fee helper only reads two integers and returns their sum. The sample dependency artifact is empty: no native service is requested for (80,10)→90 cents. This is the smallest useful bridge module, and it remains understandable without a widget, database or audio contract.

Adding import wdb because the host application eventually stores prices creates an unnecessary dependency for this calculation. Imports should follow actual API use, while later persistence belongs to a separate integration boundary.

Worked reasoning and supplied artifact

// Worked contract artifact:
// A price+fee helper only reads two integers and returns their sum. The sample dependency artifact is empty: no native service is requested for (80,10)→90 cents. This is the smallest useful bridge module, and it remains understandable without a widget, database or audio contract.

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

Inspect the helper’s operations and justify the absence of native imports.

• 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 import only the public apis you use.

Write an import-free reward helper for base 15 plus bonus 6, then identify where a future persistence integration would enter without adding it to the helper.

What to produce

A pure helper, predicted 21 points and a separate storage-consumer contract note.

• 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.

• Keep a pure pricing helper free of unnecessary imports
• Inspect the helper’s operations and justify the absence of native imports.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Inspect the helper’s operations and justify the absence of native imports.

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