Core DevPre-alpha

Sum template (.sum.xml)

SWC includes a compile-time template language for addon and core components. Files use the .sum.xml extension and compile to TypeScript html tagged literals via the esbuild plugin in core/swc/esbuild.config.mjs.

When to use

Approach	Use when
`html` `in` .ts`	Most field widgets and views (default)
`.sum.xml`	Larger templates with many conditionals or loops

Core views use html` directly; sum-template is optional for addon authors who prefer XML-like markup.

Directives

Directive	Compiles to
`t-if="expr"`	`when(expr, () => html`…`)`
`t-elif="expr"`	Chained `when`
`t-else`	Else branch of `when`
`t-foreach="item in items" t-key="item.id"`	`forEach(items, …)`
`t-esc="expr"`	`${expr}` (escaped)
`t-raw="expr"`	`${expr}`
`t-model="expr"`	Two-way `@input` + `value` bind
`t-component="MyComponent"`	`mountComponent(MyComponent, …)`
`t-ref="name"`	`data-ref="name"` attribute
`t-portal="target"`	`data-portal="target"` attribute
`t-slot="name"`	`data-slot="name"` attribute
`{{ expr }}`	Interpolation

Example

MyPanel.sum.xml:

<div class="sum-my-panel">
  <div t-foreach="item in items" t-key="item.id">
    <span t-if="item.active">{{ item.name }}</span>
  </div>
</div>

Compiles to a TypeScript module exporting a template function used by SwcComponent.template().

Limitations

t-slot, t-portal, and t-ref emit data attributes only — there is no runtime slot-filling or portal API yet.
t-model is compile-time binding; no centralized v-model runtime.
Compiler lives in core/swc/src/template/sum/; tests in tests/template/sum-compiler.test.ts.

Build