Define component parameter contracts — Boundary detective

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

Reject a boundary error before native allocation

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.

A Graph component requires pointCount integer1..1000. The host allocates a native buffer only after validation. Requests0,1,1000 and1001 arrive independently.

Worked reasoning: Reject0 and1001 without allocating. Accept1 and1000 and then request the bounded allocation. This ordering prevents invalid requests consuming native resources before rejection.

Failed alternative: Allocating first and validating later can create unnecessary ownership and cleanup obligations on every invalid request.

Worked reasoning and supplied artifact

pointCount0 ->reject;allocations0
pointCount1 ->accept;allocation1 point
pointCount1000 ->accept;allocation1000 points
pointCount1001 ->reject;allocations0

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.

Define an ImageStrip frameCount1..64 and show validation/allocation outcomes for0,1,64,65.

What to produce

A validation-before-acquisition flow and boundary allocation table.

• 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.

• Reject a boundary error before native allocation
• Define an ImageStrip frameCount1..64 and show validation/allocation outcomes for0,1,64,65.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Place the native acquisition boundary after cheap local preconditions.

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