Arrange a column and spacing — Boundary detective

PART I

Warm-up

Reconnect with a useful idea before starting arrange a column and spacing. 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

Detect overflow at a precise boundary

Column layout combines ordered children with padding, gaps and available space. The source shows padding [24,32] and gap16 but does not settle every measurement convention. Each exercise supplies its own explicit geometry contract; do not generalize that contract into a universal WUIX guarantee.

Available height is100. Children have heights30 and30, gap12, and vertical padding14 each side. Host contract: an over-budget column is reported as overflow; it does not silently shrink children.

Worked reasoning: Required height is14+30+12+30+14=100, so the column exactly fits. Increasing gap to13 needs101 and overflows by1. Equality is a fit under the supplied rule.

Failed alternative: Treating required>=available as overflow rejects the exact-fit case and hides the inclusive fit boundary.

Worked reasoning and supplied artifact

Gap12: required100, available100, overflow0 ->fit
Gap13: required101, available100, overflow1 ->overflow
Gap11: required99, available100, spare1 ->fit

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: Operations dashboard. Build a small, understandable change around arrange a column and spacing.

Find the largest fitting gap for two height24 children, vertical padding10 and available height80. Include one below, exact and one above case.

What to produce

A three-row capacity table and the algebra for the maximum gap.

• 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.

• Detect overflow at a precise boundary
• Find the largest fitting gap for two height24 children, vertical padding10 and available height80. Include one below, exact and one above case.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Subtract padding and child heights before assigning the gap budget.

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