E0153: A second template in a template file

A .vuka.html file renders one struct, the one its header declares: its markup is that struct's, and nothing follows it. A func line after the markup starts a second template — a partial, a function component, a method of another type — which a file no longer holds.

A partial becomes its own component: a .vuka.html file whose struct's exported fields are the partial's parameters (a Children ui.Node field takes what is written between its tags), used as a tag. A piece that builds nodes from other components without markup of its own may be a Go function returning ui.Node in a .go file.

Wrong

<!-- list.vuka.html -->
<script lang="go">
package pages

type List struct {
	Items []string
}
</script>

<ul>
  for _, it := range Items {
    <Row text={it} />
  }
</ul>

func Row(text string)
<li>{text}</li>

Right

<!-- list.vuka.html -->
<script lang="go">
package pages

type List struct {
	Items []string
}
</script>

<ul>
  for _, it := range Items {
    <Row text={it} />
  }
</ul>

<!-- row.vuka.html -->
<script lang="go">
package pages

type Row struct {
	Text string
}
</script>

<li>{Text}</li>