Import only the public APIs you use — Change one requirement

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

Adapt an import when an API moves

An import names a dependency; it does not implement or authorize it. Import only the public surfaces the script actually uses. The source describes Library → Module → Submodule → API → Parameters. Read that hierarchy to identify the required surface while keeping host resources and capability grants separate. Import syntax cannot prove a service exists at runtime or that the script may use every resource behind it.

Provider version A exposes totalRule in a pricing module. Version B documents a new public pricing.rules surface, while keeping a compatibility adapter for A during a transition. No exact new import grammar is supplied.

Build a dependency inventory with required symbol, public provider, purpose and host requirement. Remove unused dependencies only after checking transitive behavior and the stated contract. For unresolved API signatures, document what must be supplied rather than inventing a convenient method. Worked case: A migration plan records the old and new public provider paths, preserves input/result meaning, and tests both client cohorts on the same values. Describe the intended dependency before writing unverified syntax.

Compare the tempting alternative: Editing the import path alone cannot prove the new API has the same signature or that the old client still resolves its dependency.

Worked reasoning and supplied artifact

// Paper trace / supplied exercise-host contract; no execution claimed.
// Provider version A exposes totalRule in a pricing module. Version B documents a new public pricing.rules surface, while keeping a compatibility adapter for A during a transition. No exact new import grammar is supplied.
// A migration plan records the old and new public provider paths, preserves input/result meaning, and tests both client cohorts on the same values. Describe the intended dependency before writing unverified syntax.

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 import only the public apis you use.

Create old-client/new-client rows for subtotal=18, fee=2 and document the adapter’s expected result 20. List the provider evidence needed to finalize syntax.

What to produce

A dependency migration table with signature and compatibility checks.

• 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.

• Adapt an import when an API moves
• Create old-client/new-client rows for subtotal=18, fee=2 and document the adapter’s expected result 20. List the provider evidence needed to finalize syntax.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Name one compatibility fact your adapter must preserve.

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