Html

An element. Void ness is a property of the tag name, looked up in an internal void tag table at render time, so Element("br", …, void = false) is not a state that exists.

key is a field rather than an ordinary attribute because modules/live addresses list children by identity, and a requirement one module places on another belongs in a type rather than in a string two modules agree on by convention. It renders as data-eezo-key.

Several nodes with no element of their own.

A Fragment renders its children and nothing of its own, so one tree child can become several DOM nodes, and every index after it would run ahead of the tree if the fragment were left in place. For example, div(span("a"), text("x") ++ text("y"), span("z")) renders `

axyz, which a browser parses as three DOM children; left unspliced, the two text nodes would sit behind one tree child. [[Tag.apply]] is the guard: it splices aFragmentchild into its parent's children, then merges adjacentTextchildren and drops empty ones, because the parser knows no boundary betweenxandyeither, so anElementbuilt through a tag holds exactly three children here and tree child index equals DOM child index. That guard isTag.apply's alone; building anElementby hand with aFragmentamong its children, or nesting oneFragment` inside another before it reaches a tag, sits outside it. The case survives as a root level value, where there is no parent to index into.

The single unescaped path into the tree.

Mounting stops at its layer. Route.under moves a Url.Mounted wherever one sits in an attribute, and raw content is a string eezo never parses, so a link written inside it keeps whatever it says and stays where the author put it.

Text that is already escaped. The constructor is package private, so Html.text is the only way to build one from outside io.eezo.core.html, while the pattern match that the differ in modules/live needs still compiles from anywhere.