MenuBar

Wire names menubar · menu · menuitem

An application's menu bar. Three types build it: a menubar holds menus, each menu holds menuitems, and choosing an item raises a command event naming what was asked for.

mb=new menubar children={
	new menu caption="&File" wellknown="file" children={
		new menuitem caption="&New" shortcut="^N" action=app.file.new
		new menuitem caption="&Open…" shortcut="^O" action=app.file.open
		new menuitem separator
		new menuitem caption="&Quit" shortcut="^Q" action=app.quit
	}
}

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A menu bar is top-level, not a window child

This is the part that catches people. A menubar is not placed inside a window's children. It is built as its own top-level object in the same request, and the display adopts it as the connection's application chrome — the same way it adopts a window and a statusbar:

w=new window title="My App" width=480 height=288 main children={
	new panel layout=vbox children={ … }
}
mb=new menubar children={ … }

A window takes exactly one content trinket, so anything with several parts goes in a Panel — asking for two is an error that says so.

Properties

menu

Property	Type	Default	Meaning
after	string	—	Place this untagged menu after a well-known slot (e.g. after=file)
caption	string	—	Menu title (& marks accelerator)
wellknown	string	—	System role tag: app/file/edit/format/view/window/help

menuitem

Property	Type	Default	Meaning
action	word	—	Command id dispatched on activation
caption	string	—	Item label (& marks accelerator)
checkable	flag	false	Item can be checked
checked	flag	false	Checked state
enabled	flag	true	Item is enabled
inplace	flag	false	Activation acts in place: the menu stays open.
separator	flag	false	Render as a separator line
shortcut	string	—	Keyboard shortcut (e.g. "^N")
shortcuttext	string	—	Literal text for the shortcut column, for keys the host handles itself (appended after any shortcut)
wellknown	string	—	System item role: cut/copy/paste/selectall - this item BECOMES the standard one

menubar itself takes no properties; it is a holder.

menu and menuitem are the exception to the usual rule about common properties: menubar and menuitem are virtual types and do not take them. That is why menuitem carries its own enabled.

Events

command — The item was chosen. Carries the command it names rather than the item's identity, because a command is what an application binds to and the same one may be reachable from several menus.

Field	Type	Meaning
action	word	The command ID the item names.

Choosing an item raises command carrying the item's action, exactly as a Button with action= does. That is the point: a client binds handlers to command IDs and does not care whether a button, a menu item or a keyboard shortcut reached it.

conn.OnCommand("app.file.new", func() { … })

Every item raises command, whether or not you gave it an action=. An item without one is assigned a generated ID — cmd.auto.5 and the like — and that is what arrives:

new menuitem caption="Cu&t" wellknown="cut"
  ->  command with action = "cmd.auto.5"

So an unhandled item is not silent; it reports something your handler table will not recognise. Give an item an action= if you mean to act on it.

Mnemonics: & in a caption

Unlike every other trinket, menu and menuitem parse & in their caption. The marked letter becomes the accelerator and the & is removed from what is drawn:

Caption	Shown
"&File"	File
"Cu&t"	Cut
"Save && Close"	Save & Close

&& is the escape for a literal ampersand. Assignment is greedy across siblings, so an item whose marked letter is already taken falls back to another letter from its label — which is why you can mark the obvious letter everywhere and let the bar sort itself out.

This markup is menu-only. A Button captioned "&Save" paints the ampersand.

Shortcuts

Three different things can fill an item's shortcut column.

Property	For
shortcut	A key this item binds, written in the key vocabulary — "^N", "s-Q".
shortcuttext	Literal text for a key the host handles, which the toolkit does not bind but which still deserves advertising. Appended after any shortcut.
(neither)	Nothing shown.

shortcut="^N" both binds the key and prints it. shortcuttext="F10" prints only — use it when something else already owns the key.

Item kinds

new menuitem separator                                     # a rule
new menuitem caption="&Word Wrap" checkable checked action=app.view.wrap
new menuitem caption="Not yet" !enabled
new menuitem caption="Stays open" inplace action=app.tweak

separator draws a rule and holds no label.

checkable / checked give the item a check mark. The item still raises command on activation; the check state is yours to keep in step by setting checked back.

inplace keeps the menu open after activation instead of dismissing it — for a run of toggles a user flips several times, like a column chooser. Escape or a click away still closes it.

!enabled greys the item and refuses activation.

Well-known roles

wellknown tags a menu or an item with a standard role, and the desktop merges it with the host's own chrome rather than showing two of everything.

On	Values
menu	app file edit format view window help
menuitem	cut copy paste selectall

A tagged item becomes the standard one — your "Cu&t" with wellknown="cut" is the Cut command, in the place the platform expects it, rather than a second Cut beside it.

after= places an untagged menu relative to a tagged slot — after=file puts your menu just past the File menu — so a custom menu can be positioned without claiming a role it does not have.

See also

Button — the other way to raise command · StatusBar · Desktop · Templates and Aliases — for repeated menu shapes