WML 1.1 Engine Support Plan (MVP)

Status: earlier draft. Superseded by docs/wml-engine/source-material-review.md, docs/wml-engine/requirements-matrix.md, and docs/wml-engine/ticket-plan.md.

Purpose

Implement a WML 1.1 runtime that parses decks/cards and renders constrained viewport output with deck/card navigation semantics.

Transport -> WASM normalized handoff

The transport layer must normalize either WML media type:

text/vnd.wap.wml
application/vnd.wap.wmlc (WBXML tokenized form)

into a single engine input shape:

{
  "wmlXml": "<wml>...</wml>",
  "baseUrl": "http://example.com/index.wml",
  "contentType": "text/vnd.wap.wml",
  "rawBytesBase64": "..."
}

Required fields:

wmlXml
baseUrl
contentType

Optional field:

rawBytesBase64 (debug/fidelity path)

DTD-aligned parser target

WML 1.1 root model to target:

<wml> with (head?, template?, card+)

Card model baseline for runtime evolution:

<card> containing paragraph/task/event structures

MVP parser accepts:

<wml>
<card id="...">
<p>
<br/>
<a href="...">

Runtime model

Maintain:

Deck (cards keyed by id)
Active card
Focusable links and focused index
Navigation history stack

MVP:

href="#cardId" -> in-deck card switch
external/relative href -> host-handled navigation request (current Rust MVP keeps this as host responsibility)

v2+:

<do> tasks: go | prev | noop | refresh
<go href="..."> with postfield|setvar
variable substitution across text/attributes

Layout rules (MVP)

fixed viewport columns
vertical flow
text wrapping
focused link highlight
one card rendered at a time

Success criteria

wasm module loads in host
first card renders
focused link changes with up/down
enter navigates #cardId
render list updates deterministically