Part the source into adf/ and markdown/ ahead of the parser

src/markdown/directive-attributes.ts

@@ -0,0 +1,41 @@
+import type { JsonValue } from '../json-value.ts'
+import type { VocabularyPair } from '../adf/attribute-vocabulary.ts'
+import { serializeCanonicalJson } from '../canonical-json.ts'
+
+const bareToken = /^[A-Za-z0-9_-]+$/
+
+// spec/flavour.md, Attributes.
+const quotedEscapes = /[&<`|]/g
+
+export function isBareToken(text: string): boolean {
+  return bareToken.test(text)
+}
+
+export function spellAttributes(pairs: readonly (readonly [string, string])[]): string {
+  if (pairs.length === 0) return ''
+  const spelled = [...pairs].sort(([left], [right]) => (left < right ? -1 : 1)).map(([key, value]) => `${key}=${value}`)
+  return `{${spelled.join(' ')}}`
+}
+
+export function spellVocabulary(pairs: readonly VocabularyPair[]): [string, string][] {
+  return pairs.map((pair): [string, string] => [pair.key, spellAttributeValue(pair)])
+}
+
+export function spellJsonAttribute(value: JsonValue): string {
+  return quote(serializeCanonicalJson(value, 'compact'))
+}
+
+export function spellStringAttribute(text: string): string {
+  return isBareToken(text) ? text : quote(text)
+}
+
+function spellAttributeValue(pair: VocabularyPair): string {
+  if (pair.kind === 'boolean') return `${pair.value}`
+  if (pair.kind === 'json') return spellJsonAttribute(pair.value)
+  if (pair.kind === 'number') return spellStringAttribute(JSON.stringify(pair.value))
+  return spellStringAttribute(pair.value)
+}
+
+function quote(text: string): string {
+  return JSON.stringify(text).replace(quotedEscapes, (character) => `\\u${character.charCodeAt(0).toString(16).padStart(4, '0')}`)
+}