Define component parameter contracts — Change one requirement

PART I

Warm-up

Reconnect with a useful idea before starting define component parameter contracts. 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 a component without changing its consumers

A component parameter contract states representation, meaning, allowed range, defaults and update behavior. A correct-looking configuration can violate any one of these. Keep the public contract independent from the native hosts private implementation; proposed WS object notation does not validate inputs by itself.

Existing clients pass padding12 to a Card, meaning12 logical units on every edge. A new implementation internally stores vertical/horizontal pairs. The public padding parameter must remain compatible.

Worked reasoning: Adapt old padding12 to internal pair[12,12]. Old clients then keep identical edges. A new asymmetric feature needs a separate documented entry rather than reinterpreting12 as vertical-only.

Failed alternative: Changing the meaning of an unchanged parameter breaks clients even though their source still parses.

Worked reasoning and supplied artifact

Old request:padding12 ->top12,bottom12,left12,right12
New internal adapter:[vertical12,horizontal12]
Observable result:all four edges remain12
Compatibility target:unchanged clients

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: Accessible service console. Build a small, understandable change around define component parameter contracts.

Migrate an all-edges margin8 implementation to internal pairs while preserving existing callers. Specify how a separately named asymmetric option would avoid ambiguity.

What to produce

A public-to-internal mapping and unchanged-client acceptance case.

• 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.

import wuix.widget.button;
import wuix.layout;
domain Login {
    const screen = {
        layout: { type: "column", padding: [24, 32], gap: 16 },
        components: [{ type: "text", value: "Welcome back" }]
    };
    fnc show() -> void {
        wuix.mount("main", screen);
    }
}

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 a component without changing its consumers
• Migrate an all-edges margin8 implementation to internal pairs while preserving existing callers. Specify how a separately named asymmetric option would avoid ambiguity.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Compare observable parameter meaning before and after internal redesign.

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