attributes.toml

attributes.toml is optional. It sits next to theme.toml and goes into the package unchanged. attributes.toml in the Themes guide explains how to use it.


Schema	`https://umono.dev/schemas/theme-attributes/v1`
Format	TOML v1.0.0, UTF-8
Checked against	The contract in the package, by `build`, `install` and activation

schema = "https://umono.dev/schemas/theme-attributes/v1"

[address."post"]
class = "folio-post"

[address."post IMAGE"]
sizes = "(min-width: 48rem) 41rem, 100vw"

Keys

Key	Type	Required	Rule
`schema`	string	Yes	Exactly `https://umono.dev/schemas/theme-attributes/v1`
`address`	table	Yes	At least one address

No other top-level key is allowed.

Addresses

Each key of address is an address, written with single spaces between its parts. Leading, trailing and repeated spaces are errors.

Form	Example	Element
`layout`	`post`	`<umono-root>`
`layout BUILTIN`	`post IMAGE`	The root element of every such built-in in the scope of the layout
`layout COMPONENT BUILTIN`	`post MAIN_MENU LINK`	The root element of every such built-in in the scope of the component

layout is a layout id of the contract.
COMPONENT is a component the contract exposes (expose = true).
BUILTIN is one of LINK, IMAGE, NAV, LIST, DETAILS, HEADER, MAIN, FOOTER, ARTICLE and ASIDE. A name the contract defines as a component is not a built-in.
layout COMPONENT is not an address.
A name that the contract does not have is an error. An address whose layout never uses its component is a warning.

Built-in	Root element
`LINK`	`a`
`IMAGE`	`picture`
`NAV`	`nav`
`LIST`	`ul` or `ol`
`DETAILS`	`details`
`HEADER`	`header`
`MAIN`	`main`
`FOOTER`	`footer`
`ARTICLE`	`article`
`ASIDE`	`aside`

Attributes

The value of each address is a table with at least one attribute. Values are strings.

Attribute	Addresses	Written to	Value
`class`	All	The element of the address	Class names separated by single spaces. Printable ASCII (U+0021–U+007E), no repeated name, no name starting with `umono-` or `compono-` (in any case), at most 1024 bytes
`sizes`	Ending in `IMAGE`	Every element with a `srcset` in the image	The HTML source size list, with the media features and length units of Theme CSS, and `calc()`, `min()`, `max()` and `clamp()`. No `auto`, no percentages, no media types

The values are escaped in the HTML. Compono writes neither attribute on these elements itself, so the value of the theme is the only value.