Read the emphasis, the links and the lone image CommonMark spells (#34)

src/adf/editor-normal.ts

@@ -0,0 +1,32 @@
+import type { AdfMark, AdfNode } from './document.ts'
+import { serializeCanonicalJson } from '../canonical-json.ts'
+
+export function sameMark(candidate: AdfMark, mark: AdfMark): boolean {
+  return markKey(candidate) === markKey(mark)
+}
+
+// AGENTS.md §2: adjacent text nodes carrying identical marks are one node.
+export function mergeAdjacentText(nodes: readonly AdfNode[]): AdfNode[] {
+  const merged: AdfNode[] = []
+  for (const node of nodes) {
+    const previous = merged[merged.length - 1]
+    if (previous !== undefined && previous.type === 'text' && node.type === 'text' && sameMarks(previous, node)) {
+      merged[merged.length - 1] = { ...previous, text: `${previous.text ?? ''}${node.text ?? ''}` }
+      continue
+    }
+    merged.push(node)
+  }
+  return merged
+}
+
+function sameMarks(previous: AdfNode, node: AdfNode): boolean {
+  return marksKey(previous.marks ?? []) === marksKey(node.marks ?? [])
+}
+
+function marksKey(marks: readonly AdfMark[]): string {
+  return marks.map(markKey).join('\n')
+}
+
+function markKey(mark: AdfMark): string {
+  return `${mark.type} ${serializeCanonicalJson(mark.attrs ?? {}, 'compact')}`
+}