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UI.Stack

luastra/ui
UI.Stack(input: Input): Node

Offers a concise vertical composition primitive with the same layout direction as Column and stack-specific host styling. Children remain in normal flow and do not overlap.

Mental model

This is a declarative node: app.render describes it again from current state, while the host matches its stable id to the existing view.

Before you use it

Add luastra/ui to this module's dependencies in luastra.json, then import it with require("luastra/ui"). The project must declare the ui.render capability. app.render must return one UI.Screen root; place this node inside that tree rather than invoking it for a hidden side effect.

How it fits

The constructor validates its fields immediately and returns a UI.Node. After app.render returns, the host reconciles that node by stable id with the current semantic DOM-based interface. Current desktop and mobile hosts package the same web artifact; native adapters are used at capability boundaries.

When to use it

Use UI.Stack for straightforward vertical groups where the semantic name improves readability. Use UI.Column when you want the canonical general-purpose vertical container or need examples shared across all hosts.

Shared parameter groups

layoutsemantic

Parameters

ParameterType / valuesDescription
idlowercase path, requiredUnique ID.
childrenUI.Node[]Vertical stack; semantically equivalent to Column.
gapnone | xs | sm | md | lg | xlSpace between children. Group: Layout and surfaces.
paddingnone | xs | sm | md | lg | xl | responsiveAll-side inner spacing; responsive is supported only by padding. Group: Layout and surfaces.
marginnone | xs | sm | md | lg | xlAll-side outer spacing. Group: Layout and surfaces.
paddingX / paddingYnone | xs | sm | md | lg | xlAxis-specific inner spacing. Group: Layout and surfaces.
paddingTop / paddingBottom / paddingStart / paddingEndnone | xs | sm | md | lg | xlLogical side-specific inner spacing. Group: Layout and surfaces.
marginX / marginYnone | xs | sm | md | lg | xlAxis-specific outer spacing. Group: Layout and surfaces.
marginTop / marginBottom / marginStart / marginEndnone | xs | sm | md | lg | xlLogical side-specific outer spacing. Group: Layout and surfaces.
surfaceplain | card | elevated | accentBackground, border, and elevation. Group: Layout and surfaces.
widthfull | content | wideAvailable width, 720 px maximum, or 1180 px maximum. Group: Layout and surfaces.
alignstart | center | end | stretch | betweenCross-axis alignment. Group: Layout and surfaces.
justifystart | center | end | betweenMain-axis alignment. Group: Layout and surfaces.
flowwrap | nowrapFlex wrapping. Group: Layout and surfaces.
responsivebooleanNarrow-screen adaptation. Group: Layout and surfaces.
classNamesafe string ≤ 256 bytesAdditional admitted class tokens. Group: Layout and surfaces.
tonemuted | error | successSemantic text tone. Group: State and semantics.
appearanceprimary | secondary | danger | ghostAction appearance. Group: State and semantics.
variantbody | subheading | heading | titleBody text or h3, h2, and h1 heading semantics. Group: State and semantics.
rolealert | group | statusSupported ARIA role. Group: State and semantics.
labelstringAccessible name. Group: State and semantics.
hiddenbooleanVisibility state. Group: State and semantics.
disabledbooleanDisabled state. Group: State and semantics.
busybooleanaria-busy state. Group: State and semantics.
requiredbooleanRequired input state. Group: State and semantics.
errorIdcomponent idAssociates a visible role=alert. Group: State and semantics.
textColortoken | #RRGGBBLocal or inherited foreground. Group: Text and local colors.
backgroundColortoken | #RRGGBBComponent-box background. Group: Text and local colors.
Color tokensaccent | danger | muted | surface | success | text | transparent | warningCurrent Screen theme colors. Group: Text and local colors.

Children and layout

Vertical stack; semantically equivalent to Column.

Accessibility and keyboard

A stable id, logical render-tree order, and visible labels preserve predictable keyboard and screen-reader navigation.

Common mistakes

  • Using a duplicate id or an uppercase path segment.
  • Passing a shared-group parameter that is not listed on this component page.

Returns

Node — a validated declarative UI node that becomes part of the next host-neutral render tree.

What happens next

A validated declarative node appears after it is returned as part of the current render tree.

Failures and fixes

Invalid fields, duplicate IDs, unsupported child combinations, or a missing ui.render capability fail during check, render-tree validation, or host startup.

Availability

Source API in 0.5.0-alpha; the public installer targets 0.5.0-alpha. Verify host-specific behavior against the selected SDK.

Focused example

UI.Stack {
    id = "article/frame",
    width = "wide",
    gap = "lg",
    UI.Text { id = "article/title", text = "Guide", variant = "title" },
    UI.Text { id = "article/body", text = "Readable content" },
}

Continue learning

Prerequisites

UI.Column

Companions

UI.RowUI.Scroll

Complete inventory

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