Markup & UI

AIVI markup is an expression language for UI trees. It looks XML-like, but it is part of the language surface and participates in ordinary AIVI binding rules.

Basic widgets

value view =
    <Window title="Greeting">
        <Box>
            <Label text="Hello" />
            <Label text="World" />
        </Box>
    </Window>

Capitalised tags name widgets or components. Attributes can be plain text or embedded expressions.

Binding expressions into attributes

value header = "Users"

value view =
    <Window title="Directory">
        <Label text={header} />
    </Window>

Anything inside {...} is an AIVI expression.

Typed widget properties

Widget attributes are schema-checked host properties, not an open CSS map. That means you bind ordinary expressions into the properties a widget exposes today.

type Bool -> Float
func previewOpacity = arg1 => arg1
 T|> 1.0
 F|> 0.25

value previewVisible = True

value view =
    <Window title="Preview">
        <Button label="Blue" animateOpacity={True} opacity={previewOpacity previewVisible} />
    </Window>

Button.opacity takes a Float and the GTK host clamps it into the 0.0 to 1.0 range. Button.animateOpacity takes a Bool and enables the built-in opacity transition class, so changes to opacity fade instead of snapping.

Because these are ordinary attributes, they can be driven by any signal-backed or source-backed expression. Arbitrary cssProps maps are not part of the current AIVI surface yet.

Conditional rendering with <show>

value isVisible = True

value view =
    <Window title="Status">
        <Box>
            <show when={isVisible} keepMounted={True}>
                <Label text="Visible" />
            </show>
        </Box>
    </Window>

<show> renders its body only when the condition holds.

when accepts Bool, and it also accepts the canonical truthy/falsy carriers Option, Result, and Validation (plus one outer Signal). That means request helpers such as usersResult.error or usersResult.success can plug straight into markup:

value fetchError = Some "offline"

value view =
    <Window title="Status">
        <show when={fetchError}>
            <Label text="Failed" />
        </show>
    </Window>

keepMounted stays a plain Bool.

Local bindings with <with>

type Item = {
    id: Int,
    title: Text
}

type Screen = Ready (List Item)

value screen =
    Ready [
        { id: 1, title: "Alpha" },
        { id: 2, title: "Beta" }
    ]

value view =
    <Window title="Items">
        <Box>
            <with value={screen} as={currentScreen}>
                <match on={currentScreen}>
                    <case pattern={Ready items}>
                        <each of={items} as={item} key={item.id}>
                            <Label text={item.title} />
                        </each>
                    </case>
                </match>
            </with>
        </Box>
    </Window>

<with> binds a value for the nested subtree.

Pattern matching with <match>

Markup has control nodes for the same pattern-oriented style used elsewhere in the language:

type Item = {
    id: Int,
    title: Text
}

type Screen =
  | Loading
  | Ready (List Item)
  | Failed Text

value screen =
    Ready [
        { id: 1, title: "Alpha" },
        { id: 2, title: "Beta" }
    ]

value view =
    <Window title="Items">
        <Box>
            <match on={screen}>
                <case pattern={Loading}>
                    <Label text="Loading..." />
                </case>
                <case pattern={Ready items}>
                    <each of={items} as={item} key={item.id}>
                        <Label text={item.title} />
                        <empty>
                            <Label text="No items" />
                        </empty>
                    </each>
                </case>
                <case pattern={Failed reason}>
                    <Label text={reason} />
                </case>
            </match>
        </Box>
    </Window>

Iteration with <each>

<each> renders one subtree per list item and can include an <empty> fallback when the list is empty.

Summary

Element	Meaning
<Label ... />	A widget node
<fragment>...</fragment>	Group children without an outer widget
<show when={...}>	Conditional rendering
<with value={...} as={...}>	Bind a value in markup
<match on={...}>	Pattern-based rendering
<case pattern={...}>	One match branch
<each of={...} as={...} key={...}>	Iterate a list
<empty>	Empty-list fallback inside <each>

---

See also: Building Snake — a complete application that uses every markup feature together

---

Widget catalog

Window

Top-level application window.

value view =
    <Window title="App" defaultWidth={800} defaultHeight={600}>
        <Window.titlebar>
            <HeaderBar />
        </Window.titlebar>
        <Label text="Hello, world!" />
    </Window>

Properties: title, defaultWidth, defaultHeight, resizable, modal, maximized, fullscreen, decorated, hideOnClose, visible, sensitive, opacity, hexpand, vexpand, halign, valign, widthRequest, heightRequest, marginStart, marginEnd, marginTop, marginBottom, tooltip, cssClasses, animateOpacity

• maximized (Bool) — maximize or unmaximize the window
• fullscreen (Bool) — enter or exit fullscreen mode
• decorated (Bool) — show or hide window decorations (title bar, borders)
• hideOnClose (Bool) — hide rather than destroy the window when closed

Events: onCloseRequest (Unit), onMaximize (Bool), onFullscreen (Bool)

• onMaximize fires with True when maximized, False when restored
• onFullscreen fires with True when entering fullscreen, False when leaving

HeaderBar

Title bar with optional start/end widget slots.

value view =
    <Window title="App">
        <Window.titlebar>
            <HeaderBar decorationLayout="close:">
                <HeaderBar.start>
                    <Button label="Back" />
                </HeaderBar.start>
                <HeaderBar.end>
                    <Button label="Menu" />
                </HeaderBar.end>
            </HeaderBar>
        </Window.titlebar>
        <Label text="Content" />
    </Window>

Properties: showTitleButtons, decorationLayout, centeringPolicy

• decorationLayout (Text) — overrides the system button layout; format is "left-buttons:right-buttons" where tokens include close, maximize, minimize, icon (e.g. "close:", "menu:minimize,maximize,close")
• centeringPolicy (Text) — controls title centering; "Loose" (default) centres the title when space allows, "Strict" always centres it even when the start/end widgets are asymmetric

Box

Linear layout container.

value view =
    <Window title="App">
        <Box orientation="Vertical" spacing={8}>
            <Label text="First" />
            <Label text="Second" />
        </Box>
    </Window>

Properties: orientation (Horizontal|Vertical), spacing, homogeneous

ScrolledWindow

Adds scrollbars to an inner widget.

value view =
    <Window title="App">
        <ScrolledWindow hexpand={True} vexpand={True}>
            <Box orientation="Vertical" spacing={4}>
                <Label text="Row 1" />
                <Label text="Row 2" />
            </Box>
        </ScrolledWindow>
    </Window>

Paned

Two-pane resizable splitter.

value view =
    <Window title="App">
        <Paned orientation="Horizontal" hexpand={True} vexpand={True}>
            <Paned.start>
                <Label text="Left panel" />
            </Paned.start>
            <Paned.end>
                <Label text="Right panel" />
            </Paned.end>
        </Paned>
    </Window>

ToolbarView

Adwaita toolbar container with top/bottom bars and content.

value view =
    <Window title="App">
        <ToolbarView>
            <ToolbarView.top>
                <HeaderBar />
            </ToolbarView.top>
            <Label text="Content" vexpand={True} />
        </ToolbarView>
    </Window>

Label

Text display widget.

value view =
    <Window title="App">
        <Label text="Hello, world!" wrap={True} halign="Start" xalign={0.0} />
    </Window>

Properties (extra): xalign, yalign, widthChars, singleLineMode

• xalign (F64) — horizontal text alignment within the widget; 0.0 = left, 0.5 = center, 1.0 = right
• yalign (F64) — vertical text alignment within the widget
• widthChars (I64) — minimum width in characters; useful for stable layouts
• singleLineMode (Bool) — when True, forces text to render as a single line (truncates or scrolls)

Button

Clickable button.

value view =
    <Window title="App">
        <Button label="Click me" halign="Center" />
    </Window>

Extra properties: iconName, useUnderline, receivesDefault

• iconName (Text) — symbolic icon name; when set alongside label, produces an icon+label button; when set without label, produces an icon-only button (e.g. "list-add-symbolic")
• useUnderline (Bool) — when True, a _ in label marks the next character as a mnemonic accelerator
• receivesDefault (Bool) — when True, this button activates when Enter is pressed in its window (if no focused widget intercepts the key)

Gesture events (also available on Box, Label, Image):

• onSecondaryClick (Unit) — fires on right-button / secondary-button click
• onLongPress (Unit) — fires after a long press gesture is held
• onSwipeLeft (Unit) — fires when a left-ward swipe is detected
• onSwipeRight (Unit) — fires when a right-ward swipe is detected

Entry

Single-line text input.

value view =
    <Window title="App">
        <Entry placeholder="Type something..." hexpand={True} primaryIconName="system-search-symbolic" />
    </Window>

Extra properties: primaryIconName, secondaryIconName

• primaryIconName (Text) — icon name for the leading (start) icon slot; use a symbolic icon name such as "system-search-symbolic"
• secondaryIconName (Text) — icon name for the trailing (end) icon slot; commonly used for a clear button ("edit-clear-symbolic")

Events: onChange (Text), onActivated (Unit), onFocusIn (Unit), onFocusOut (Unit)

Switch

Toggle switch.

value view =
    <Window title="App">
        <Switch active={True} halign="Center" valign="Center" />
    </Window>

CheckButton

Checkbox with label.

value view =
    <Window title="App">
        <CheckButton label="Enable feature" active={False} />
    </Window>

ToggleButton

Button that stays pressed.

value view =
    <Window title="App">
        <ToggleButton label="Bold" active={False} />
    </Window>

SpinButton

Numeric spinner input.

value view =
    <Window title="App">
        <SpinButton value={5.0} min={0.0} max={10.0} step={1.0} digits={0} />
    </Window>

Scale

Slider for numeric values.

value view =
    <Window title="App">
        <Scale value={50.0} min={0.0} max={100.0} step={1.0} drawValue={True} valuePos="Bottom" hexpand={True} />
    </Window>

Extra properties: valuePos, fillLevel

• valuePos (Text) — position of the numeric label when drawValue is True; one of "Top", "Bottom", "Left", "Right"
• fillLevel (F64) — fills the track up to this value (also enables the fill-level indicator automatically); useful for buffered-progress UIs

Image

Image display.

value view =
    <Window title="App">
        <Image iconName="folder-symbolic" pixelSize={48} halign="Center" />
    </Window>

Spinner

Activity indicator.

value view =
    <Window title="App">
        <Spinner spinning={True} halign="Center" valign="Center" />
    </Window>

ProgressBar

Progress display.

value view =
    <Window title="App">
        <ProgressBar fraction={0.6} hexpand={True} />
    </Window>

Revealer

Animated visibility toggle.

value view =
    <Window title="App">
        <Revealer revealed={True} transitionType="slide-down">
            <Label text="Now you see me" />
        </Revealer>
    </Window>

Separator

Visual divider line.

value view =
    <Window title="App">
        <Box orientation="Vertical">
            <Label text="Above" />
            <Separator orientation="Horizontal" />
            <Label text="Below" />
        </Box>
    </Window>

StatusPage

Placeholder page with icon and description.

value view =
    <Window title="App">
        <StatusPage title="Nothing here yet" description="Add items to get started" iconName="folder-open-symbolic" />
    </Window>

Clamp

Width-constraining container.

value view =
    <Window title="App">
        <Clamp maximumSize={600} tighteningThreshold={400}>
            <Label text="Content constrained to 600 px" wrap={True} />
        </Clamp>
    </Window>

Banner

Informational banner strip.

value view =
    <Window title="App">
        <Box orientation="Vertical">
            <Banner title="You are offline" buttonLabel="Retry" revealed={True} />
            <Label text="Main content" vexpand={True} />
        </Box>
    </Window>

Frame

Container with an optional label border.

value view =
    <Window title="App">
        <Frame label="Details">
            <Label text="Inside the frame" marginTop={8} />
        </Frame>
    </Window>

Viewport

Low-level scrollable viewport.

value view =
    <Window title="App">
        <ScrolledWindow vexpand={True}>
            <Viewport>
                <Label text="Scrollable content" />
            </Viewport>
        </ScrolledWindow>
    </Window>

---

Adwaita preference rows

These widgets are designed for settings/preferences UIs. They extend gtk::ListBoxRow and should be placed inside a ListBox.

ActionRow

A row with title, optional subtitle, and suffix widgets.

value view =
    <Window title="App">
        <ListBox>
            <ActionRow title="Notifications" subtitle="Allow alerts">
                <ActionRow.suffix>
                    <Switch active={True} valign="Center" />
                </ActionRow.suffix>
            </ActionRow>
        </ListBox>
    </Window>

Properties: title, subtitle, activatable
Events: onActivated (Unit)
Children: prefix (sequence — widgets placed before the title), suffix (sequence — widgets placed after the title)

ExpanderRow

An expandable row that reveals child rows.

value view =
    <Window title="App">
        <ListBox>
            <ExpanderRow title="Advanced" subtitle="More options" expanded={False}>
                <ExpanderRow.rows>
                    <ActionRow title="Option A" />
                    <ActionRow title="Option B" />
                </ExpanderRow.rows>
            </ExpanderRow>
        </ListBox>
    </Window>

Properties: title, subtitle, expanded
Events: onExpanded (Bool) — fires each time the row is expanded or collapsed
Children: rows (sequence)

SwitchRow

A preference row with an embedded switch.

value view =
    <Window title="App">
        <ListBox>
            <SwitchRow title="Dark mode" subtitle="Use dark colour scheme" active={False} />
        </ListBox>
    </Window>

Properties: title, subtitle, active
Events: onToggled (Bool — new active state)

SpinRow

A preference row with an embedded spin button.

value view =
    <Window title="App">
        <ListBox>
            <SpinRow title="Font size" value={12.0} min={8.0} max={32.0} step={1.0} />
        </ListBox>
    </Window>

Properties: title, subtitle, value, min, max, step
Events: onValueChanged (Float)

EntryRow

A preference row with an embedded text entry.

value view =
    <Window title="App">
        <ListBox>
            <EntryRow title="Username" text="" />
        </ListBox>
    </Window>

Properties: title, text
Events: onChange (Text), onActivated (Unit), onFocusIn (Unit), onFocusOut (Unit)

---

List and selection

ListBox

A vertical list container for rows.

value view =
    <Window title="App">
        <ListBox selectionMode="None">
            <ListBoxRow>
                <Label text="Row one" />
            </ListBoxRow>
            <ListBoxRow>
                <Label text="Row two" />
            </ListBoxRow>
        </ListBox>
    </Window>

Properties: selectionMode (None|Single|Browse|Multiple), showSeparators (Bool)
Events: onRowActivated (Int — zero-based row index)
Children: children (sequence)

ListBoxRow

A single row in a ListBox.

value view =
    <Window title="App">
        <ListBox>
            <ListBoxRow activatable={True}>
                <Label text="Clickable row" marginStart={12} marginEnd={12} />
            </ListBoxRow>
        </ListBox>
    </Window>

Properties: activatable
Events: onActivated (Unit)
Children: child (single)

ListView

A factory-backed GTK list for large item sequences. It accepts ordinary child widgets, but mounts them through GTK list items so scrolling stays efficient. Wrap it in a ScrolledWindow when the content should scroll.

value view =
    <Window title="App">
        <ScrolledWindow vexpand={True}>
            <ListView showSeparators={True} singleClickActivate={True} onActivate={index}>
                <Label text="Thread A" />
                <Label text="Thread B" />
                <Label text="Thread C" />
            </ListView>
        </ScrolledWindow>
    </Window>

Properties: showSeparators, enableRubberband, singleClickActivate (Bool)
Events: onActivate (Int — zero-based item index)
Children: children (sequence — default)

GridView

A factory-backed GTK grid for large tile collections. Like ListView, it accepts ordinary child widgets and virtualizes scrolling/layout through GTK’s grid item machinery.

value view =
    <Window title="App">
        <ScrolledWindow vexpand={True}>
            <GridView minColumns={2} maxColumns={4} singleClickActivate={True} onActivate={index}>
                <Button label="Card 1" />
                <Button label="Card 2" />
                <Button label="Card 3" />
                <Button label="Card 4" />
            </GridView>
        </ScrolledWindow>
    </Window>

Properties: enableRubberband, singleClickActivate (Bool), minColumns, maxColumns (Int)
Events: onActivate (Int — zero-based item index)
Children: children (sequence — default)

DropDown

A dropdown selector from a comma-separated list of strings.

value view =
    <Window title="App">
        <DropDown items="Red,Green,Blue" selected={0} halign="Start" />
    </Window>

Properties: items (comma-separated text), selected (Int)
Events: onSelectionChanged (Int — selected index)

---

Utility

SearchEntry

A text entry styled for search input with debounced onSearchChanged.

value view =
    <Window title="App">
        <SearchEntry placeholder="Search..." hexpand={True} />
    </Window>

Properties: text, placeholder
Events: onChange (Text), onActivated (Unit), onSearchChanged (Text — debounced)

Expander

A collapsible container with a label toggle.

value view =
    <Window title="App">
        <Expander label="Details" expanded={False}>
            <Label text="Hidden until expanded" />
        </Expander>
    </Window>

Properties: label, expanded
Events: onExpanded (Bool) — fires each time the expander is expanded or collapsed
Children: child (single)

---

Navigation and overlay

NavigationView

Adwaita push-based navigation stack. Children must be NavigationPage widgets.

value view =
    <Window title="App">
        <NavigationView>
            <NavigationPage title="Home" tag="home">
                <Label text="Home page" halign="Center" valign="Center" vexpand={True} />
            </NavigationPage>
            <NavigationPage title="Details" tag="details">
                <Label text="Details page" halign="Center" valign="Center" vexpand={True} />
            </NavigationPage>
        </NavigationView>
    </Window>

Children: pages (sequence of NavigationPage)

NavigationPage

A page within a NavigationView.

value view =
    <Window title="App">
        <NavigationView>
            <NavigationPage title="Profile" tag="profile">
                <ToolbarView>
                    <ToolbarView.top>
                        <HeaderBar />
                    </ToolbarView.top>
                    <Label text="Profile content" halign="Center" valign="Center" vexpand={True} />
                </ToolbarView>
            </NavigationPage>
        </NavigationView>
    </Window>

Properties: title, tag
Events: onShowing (Unit) — fired when the page is pushed onto the navigation stack; onHiding (Unit) — fired when the page is popped
Children: content (single)

ToastOverlay

An overlay that can display transient toast notifications (toasts are shown at runtime via the signal engine, not via markup children).

value view =
    <Window title="App">
        <ToastOverlay>
            <ToastOverlay.content>
                <Label text="Main content" halign="Center" valign="Center" vexpand={True} />
            </ToastOverlay.content>
        </ToastOverlay>
    </Window>

Children: content (single)

---

Preferences and forms

PreferencesWindow

An Adwaita preferences window with a searchable page switcher.

value view =
    <PreferencesWindow title="Settings" defaultWidth={600} defaultHeight={400} searchEnabled={True}>
        <PreferencesPage title="General" iconName="preferences-system-symbolic">
            <PreferencesGroup title="Appearance" description="Adjust how the app looks">
                <SwitchRow title="Dark mode" />
            </PreferencesGroup>
        </PreferencesPage>
    </PreferencesWindow>

Properties: title, defaultWidth (Int), defaultHeight (Int), searchEnabled (Bool)
Children: pages (sequence of PreferencesPage)

PreferencesPage

A named page inside a PreferencesWindow.

value view =
    <PreferencesWindow title="Settings">
        <PreferencesPage title="General" iconName="preferences-system-symbolic">
            <PreferencesGroup title="Behaviour">
                <SwitchRow title="Auto-save" active={True} />
            </PreferencesGroup>
        </PreferencesPage>
    </PreferencesWindow>

Properties: title, iconName
Children: children (sequence of PreferencesGroup)

PreferencesGroup

A titled group of preference rows within a PreferencesPage.

value view =
    <PreferencesWindow title="Settings">
        <PreferencesPage title="General" iconName="preferences-system-symbolic">
            <PreferencesGroup title="Privacy" description="Control data usage">
                <SwitchRow title="Analytics" active={False} />
                <SwitchRow title="Crash reports" active={True} />
            </PreferencesGroup>
        </PreferencesPage>
    </PreferencesWindow>

Properties: title, description
Children: children (sequence — any preference rows or widgets)

ComboRow

A preference row with a drop-down selector.

value view =
    <Window title="App">
        <ListBox>
            <ComboRow title="Theme" items="Light,Dark,System" selected={2} />
        </ListBox>
    </Window>

Properties: title, subtitle, items (comma-separated), selected (Int)
Events: onSelectionChanged (Int — zero-based index of selected item)

PasswordEntryRow

A preference row styled for password input with reveal toggle.

value view =
    <Window title="App">
        <ListBox>
            <PasswordEntryRow title="Password" text="" />
        </ListBox>
    </Window>

Properties: title, text
Events: onChange (Text), onActivated (Unit), onFocusIn (Unit), onFocusOut (Unit)

---

Layout overlays

Overlay

Stacks widgets on top of a main content widget. Use content for the base layer and overlay for widgets that float above it.

value view =
    <Window title="App">
        <Overlay>
            <Label text="Base content" halign="Center" valign="Center" hexpand={True} vexpand={True} />
            <Overlay.overlay>
                <Label text="Floating label" halign="End" valign="End" marginEnd={12} marginBottom={12} />
            </Overlay.overlay>
        </Overlay>
    </Window>

Children: content (single — base widget), overlay (sequence — overlaid widgets)

MultilineEntry

A multi-line text editor backed by gtk::TextView.

value view =
    <Window title="App">
        <MultilineEntry text="" editable={True} monospace={False} topMargin={8} bottomMargin={8} vexpand={True} />
    </Window>

Properties: text, editable (Bool), monospace (Bool), topMargin (Int), bottomMargin (Int), leftMargin (Int), rightMargin (Int)
Events: onChange (Text), onFocusIn (Unit), onFocusOut (Unit)

Picture

Displays an image from a file path or a GResource path, with configurable content-fit behaviour. Use Picture instead of Image when you need layout-aware scaling.

value view =
    <Window title="App">
        <Picture filename="/usr/share/pixmaps/logo.png" contentFit="contain" canShrink={True} hexpand={True} vexpand={True} />
    </Window>

Properties:

• filename (Text) — absolute file path to load; empty string clears the image
• resource (Text) — GResource path (e.g. /com/example/app/logo.png); empty clears
• contentFit (Text) — one of contain (default), fill, cover, scale-down
• altText (Text) — accessibility description
• canShrink (Bool) — allow the picture to shrink below its natural size (default True)

WebView

Strict embedded HTML viewer backed by WebKitGTK. Load HTML through html. Safe defaults stay on: JavaScript disabled, session/storage ephemeral, permission requests denied, and navigation/new windows blocked. When links should open externally, use portal.openUri from app state instead of relying on in-widget browsing.

value view =
    <Window title="App">
        <WebView html={"<article><h1>Hello</h1><p>Rendered by WebKit.</p></article>"} hexpand={True} vexpand={True} />
    </Window>

Properties: html (Text)

ViewStack + ViewSwitcher

ViewStack is the primary Adwaita page-navigation container. ViewSwitcher is a tab bar that presents the pages of a ViewStack. Since AIVI uses reactive state instead of cross-widget references, both widgets share state through a common visibleChildName signal rather than a direct object link.

signal activePage : Text = "home"

value view =
    <Window title="App">
        <ToolbarView>
            <ToolbarView.top>
                <HeaderBar>
                    <ViewSwitcher policy="Wide" />
                </HeaderBar>
            </ToolbarView.top>
            <ViewStack visibleChildName={activePage}>
                <ViewStack.pages>
                    <ViewStackPage name="home" title="Home" iconName="go-home-symbolic">
                        <Label text="Home page" halign="Center" valign="Center" vexpand={True} />
                    </ViewStackPage>
                    <ViewStackPage name="search" title="Search" iconName="edit-find-symbolic">
                        <Label text="Search page" halign="Center" valign="Center" vexpand={True} />
                    </ViewStackPage>
                </ViewStack.pages>
            </ViewStack>
        </ToolbarView>
    </Window>

ViewStack properties:

• visibleChildName (Text) — name of the currently visible page

ViewStack events:

• onSwitch (Text) — fires with the name of the newly visible page when navigation changes

ViewStack children:

• pages — sequence of child widgets; each is added as a named page via add_named. To assign a name to a page, set the child widget's GObject name property via the visibleChildName setter on the stack or use reactive state.

ViewSwitcher properties:

• policy (Text) — "Narrow" (icon-only) or "Wide" (icon + label); default Narrow

Note: ViewSwitcher does not automatically link to a ViewStack in AIVI's declarative model. Connect them reactively: bind the ViewStack.visibleChildName signal to both the stack and a switcher state signal.

AlertDialog

AlertDialog is a modal Adwaita dialog with configurable response buttons. Present and dismiss it by binding a Bool signal to the visible property.

signal showConfirm : Bool = False
signal lastResponse : Text = ""

value view =
    <Window title="App">
        <AlertDialog visible={showConfirm} heading="Delete item?" body="This action cannot be undone." defaultResponse="delete" closeResponse="cancel" responses="delete:Delete:destructive|cancel:Cancel"></AlertDialog>
        <Button label="Delete" cssClasses="destructive-action"></Window>
    </Window>
``` — `True` presents the dialog, `False` closes it
- `heading` (Text) — dialog heading text
- `body` (Text) — dialog body text
- `defaultResponse` (Text) — ID of the response activated by pressing Enter
- `closeResponse` (Text) — ID of the response used when the dialog is closed by the user
- `responses` (Text) — pipe-separated list of `id:Label` or `id:Label:appearance` entries,
  where appearance is one of `default`, `suggested`, `destructive`.
  Example: `"ok:OK:suggested|cancel:Cancel"`

**Events:**
- `onResponse` (Text) — fires with the response ID when the user activates a response

### `Calendar`

Month calendar with optional day selection.

```aivi
signal selectedDay : Int = 1
signal selectedMonth : Int = 0
signal selectedYear : Int = 2025

value view =
    <Window title="App">
        <Calendar year={selectedYear} month={selectedMonth} day={selectedDay} onDaySelected={.}></Window>
    </Window>

Properties: year, month, day

• year (I64) — displayed year
• month (I64) — displayed month, 0-based (0 = January, 11 = December)
• day (I64) — selected day of the month (1–31)

Events:

• onDaySelected (Unit) — fires when the user clicks a day

FlowBox + FlowBoxChild

Reflowing grid of child widgets. Children wrap to the next row when the available width is exhausted.

value view =
    <Window title="App">
        <ScrolledWindow hexpand={True} vexpand={True}>
            <FlowBox selectionMode="Single" rowSpacing={6} columnSpacing={6}>
                <FlowBoxChild>
                    <Label text="Item A" />
                </FlowBoxChild>
                <FlowBoxChild>
                    <Label text="Item B" />
                </FlowBoxChild>
                <FlowBoxChild>
                    <Label text="Item C" />
                </FlowBoxChild>
            </FlowBox>
        </ScrolledWindow>
    </Window>

FlowBox properties: selectionMode, rowSpacing, columnSpacing

• selectionMode (Text) — "None", "Single", "Browse", or "Multiple"
• rowSpacing (I64) — pixels of space between rows
• columnSpacing (I64) — pixels of space between columns

FlowBox events:

• onChildActivated (Unit) — fires when a child is activated (double-clicked or Enter)

FlowBox children: children — sequence of FlowBoxChild widgets

FlowBoxChild children: content — single child slot (the widget displayed inside the cell)

MenuButton

A button that opens a Popover when clicked.

signal menuOpen : Bool = False

value view =
    <Window title="App">
        <Window.titlebar>
            <HeaderBar>
                <HeaderBar.end>
                    <MenuButton iconName="open-menu-symbolic" onToggled={open => menuOpen}>
                        <MenuButton.popover>
                            <Popover>
                                <Popover.content>
                                    <Box orientation="Vertical" spacing={4} marginTop={8} marginBottom={8} marginStart={8} marginEnd={8}>
                                        <Button label="Settings" />
                                        <Button label="About" />
                                    </Box>
                                </Popover.content>
                            </Popover>
                        </MenuButton.popover>
                    </MenuButton>
                </HeaderBar.end>
            </HeaderBar>
        </Window.titlebar>
        <Label text="Content" />
    </Window>

Properties: label, iconName, active, useUnderline

• label (Text) — button label text (use iconName for icon-only buttons)
• iconName (Text) — icon name from the icon theme (e.g. "open-menu-symbolic")
• active (Bool) — whether the popover is currently open
• useUnderline (Bool) — interpret _ in the label as a mnemonic underline

Events:

• onToggled (Bool) — fires with True when the popover opens, False when it closes

Children: popover — single Popover child slot

Popover

A floating overlay widget anchored to its parent. Typically used as the child of MenuButton.

value view =
    <Window title="App">
        <MenuButton label="Options">
            <MenuButton.popover>
                <Popover autohide={True} hasArrow={True} onClosed={.}>
                    <Popover.content>
                        <Label text="Hello from popover!" marginStart={8} marginEnd={8} marginTop={8} marginBottom={8} />
                    </Popover.content>
                </Popover>
            </MenuButton.popover>
        </MenuButton>
    </Window>

Properties: autohide, hasArrow

• autohide (Bool) — close the popover automatically when focus leaves it (default True)
• hasArrow (Bool) — draw a pointing arrow towards the anchor widget (default True)

Events:

• onClosed (Unit) — fires when the popover is dismissed

Children: content — single child slot for the popover body widget

---

CenterBox

A three-slot horizontal container that aligns a center child between optional start and end children.

value view =
    <Window title="App">
        <CenterBox hexpand={True}>
            <CenterBox.start>
                <Button label="Back" />
            </CenterBox.start>
            <CenterBox.center>
                <Label text="Title" />
            </CenterBox.center>
            <CenterBox.end>
                <Button label="Forward" />
            </CenterBox.end>
        </CenterBox>
    </Window>

Children: start (single), center (single — default), end (single)

---

AboutDialog

Adwaita About dialog showing application metadata. Acts as a top-level window; set visible reactively to show or hide it.

value view =
    <Window title="App">
        <AboutDialog visible={showAbout} appName="My App" version="1.0.0" developerName="Jane Doe" website="https://example.com" issueUrl="https://github.com/example/issues" licenseType="MIT" applicationIcon="my-app" />
        <Button label="About" onClick={True}></Window>
    </Window>

Properties: visible, appName, version, developerName, comments, website, issueUrl, licenseType, applicationIcon

• licenseType (Text) — one of the GLib/GTK license identifiers: "MIT", "GPL-2.0", "GPL-3.0", "LGPL-2.1", "LGPL-3.0", "AGPL-3.0", "Apache-2.0", "MPL-2.0", "Custom", "Unknown"

---

SplitButton

A combined button + dropdown arrow that opens a Popover for secondary actions.

value view =
    <Window title="App">
        <SplitButton label="Save" onClick={.} hexpand={False}>
            <SplitButton.popover>
                <Popover>
                    <Popover.content>
                        <Box orientation="Vertical" spacing={4}>
                            <Button label="Save As…" />
                            <Button label="Export…" />
                        </Box>
                    </Popover.content>
                </Popover>
            </SplitButton.popover>
        </SplitButton>
    </Window>

Properties: label, iconName

• label (Text) — text for the main button half
• iconName (Text) — icon name alternative to label

Events: onClick (Unit) — fires when the main button half is clicked

Children: popover (single — a Popover widget for the dropdown)

---

NavigationSplitView

An adaptive two-panel layout (sidebar + content) that collapses to a single column on narrow displays. Both panels should contain NavigationPage widgets.

value view =
    <Window title="App" defaultWidth={900} defaultHeight={600}>
        <NavigationSplitView showContent={True} sidebarWidthFraction={0.3}>
            <NavigationSplitView.sidebar>
                <NavigationPage title="Sidebar">
                    <Label text="Sidebar content" />
                </NavigationPage>
            </NavigationSplitView.sidebar>
            <NavigationSplitView.content>
                <NavigationPage title="Content">
                    <Label text="Main content" />
                </NavigationPage>
            </NavigationSplitView.content>
        </NavigationSplitView>
    </Window>

Properties: showContent, sidebarWidthFraction, minSidebarWidth, maxSidebarWidth, sidebarPosition

• showContent (Bool) — when collapsed, whether the content panel is shown (vs. the sidebar)
• sidebarWidthFraction (Float) — sidebar width as a fraction of the total width (default 0.25)
• minSidebarWidth / maxSidebarWidth (Float) — clamp sidebar width in pixels
• sidebarPosition (Text) — "Start" (default) or "End"

Events: onShowContent (Bool) — fires when showContent changes

Children: sidebar (single), content (single — default)

---

OverlaySplitView

Like NavigationSplitView but the sidebar slides over the content rather than pushing it.

value view =
    <Window title="App" defaultWidth={800} defaultHeight={600}>
        <OverlaySplitView showSidebar={sidebarOpen}>
            <OverlaySplitView.sidebar>
                <Box orientation="Vertical" spacing={8} marginStart={12} marginTop={12}>
                    <Label text="Navigation" />
                </Box>
            </OverlaySplitView.sidebar>
            <OverlaySplitView.content>
                <Label text="Content" halign="Center" valign="Center" />
            </OverlaySplitView.content>
        </OverlaySplitView>
    </Window>

Properties: showSidebar, sidebarPosition, sidebarWidthFraction, minSidebarWidth, maxSidebarWidth

• showSidebar (Bool) — show or hide the overlay sidebar
• sidebarPosition (Text) — "Start" (default) or "End"

Events: onShowSidebar (Bool) — fires when showSidebar changes

Children: sidebar (single), content (single — default)

---

TabView + TabPage + TabBar

A tabbed interface. TabView holds pages; TabBar provides the tab strip.

value view =
    <Window title="App">
        <Box orientation="Vertical">
            <TabView selectedPage={activeTab} onSelectedPageChanged={.} hexpand={True} vexpand={True}>
                <TabView.tabBar>
                    <TabBar autohide={False} expandTabs={True} />
                </TabView.tabBar>
                <TabView.pages>
                    <TabPage title="Documents">
                        <TabPage.content>
                            <Label text="Documents tab" halign="Center" valign="Center" />
                        </TabPage.content>
                    </TabPage>
                    <TabPage title="Settings" needsAttention={True}>
                        <TabPage.content>
                            <Label text="Settings tab" halign="Center" valign="Center" />
                        </TabPage.content>
                    </TabPage>
                </TabView.pages>
            </TabView>
        </Box>
    </Window>

TabView

Properties: selectedPage (Int — zero-based index)
Events: onPageAdded (Unit), onPageClosed (Unit), onSelectedPageChanged (Unit)
Children: pages (sequence of TabPage — default), tabBar (single TabBar)

TabPage

Properties: visible, title, needsAttention (Bool — shows a dot indicator), loading (Bool — shows a spinner)
Children: content (single — default)

TabBar

Properties: autohide (Bool — hides bar when there is only one page), expandTabs (Bool — tabs expand to fill the bar width)

---

Carousel + indicators

A swipe carousel backed by adw::Carousel. Attach CarouselIndicatorDots or CarouselIndicatorLines as the dots/lines child to get navigation indicators.

value view =
    <Window title="App">
        <Box orientation="Vertical" spacing={8} hexpand={True} vexpand={True}>
            <Carousel spacing={16} interactive={True} hexpand={True} vexpand={True} onPageChanged={.} onSwipeLeft={.} onSwipeRight={.}>
                <Carousel.dots>
                    <CarouselIndicatorDots />
                </Carousel.dots>
                <Carousel.pages>
                    <Label text="Page 1" halign="Center" valign="Center" />
                    <Label text="Page 2" halign="Center" valign="Center" />
                    <Label text="Page 3" halign="Center" valign="Center" />
                </Carousel.pages>
            </Carousel>
        </Box>
    </Window>

Carousel properties: spacing (Int), revealDuration (Int — ms), interactive (Bool)
Carousel events: onPageChanged (Int — zero-based page index), onSwipeLeft (Unit), onSwipeRight (Unit)
Carousel children: pages (sequence — default), dots (single CarouselIndicatorDots), lines (single CarouselIndicatorLines)

CarouselIndicatorDots and CarouselIndicatorLines have no widget-specific properties; they automatically link to their parent Carousel.

---

Grid + GridChild

A two-dimensional grid layout. Each child must be wrapped in a GridChild that specifies its position.

value view =
    <Window title="App">
        <Grid rowSpacing={8} columnSpacing={8} marginStart={12} marginEnd={12} marginTop={12} marginBottom={12}>
            <GridChild column={0} row={0} columnSpan={2}>
                <GridChild.content>
                    <Label text="Wide header" hexpand={True} />
                </GridChild.content>
            </GridChild>
            <GridChild column={0} row={1}>
                <GridChild.content>
                    <Button label="A" />
                </GridChild.content>
            </GridChild>
            <GridChild column={1} row={1}>
                <GridChild.content>
                    <Button label="B" />
                </GridChild.content>
            </GridChild>
        </Grid>
    </Window>

Grid

Properties: rowSpacing, columnSpacing (Int), rowHomogeneous, columnHomogeneous (Bool)
Children: children (sequence of GridChild — default)

GridChild

Properties: column, row, columnSpan, rowSpan (Int — default span is 1)
Children: content (single — default)

---

FileDialog

A native file-chooser dialog backed by gtk::FileChooserNative. Set visible to True to show the dialog; the response is delivered via onResponse.

value view =
    <Window title="App">
        <FileDialog visible={dialogOpen} title="Open file" mode="Open" acceptLabel="Open" cancelLabel="Cancel" onResponse={code}>
            <Button label="Open file…" onClick={True}></Window>
        </FileDialog>
    </Window>

Properties:

Property	Type	Description
visible	Bool	Show (True) or hide (False) the dialog
title	Text	Window title of the chooser
mode	Text	"Open" (default) or "Save"
acceptLabel	Text	Label for the accept button
cancelLabel	Text	Label for the cancel button

Events: onResponse (Int) — response code; 1 = accepted, 0 = cancelled (matches gtk::ResponseType)