Spell 'a text node holding its text and marks alone' once, as isPlainText

src/adf/document.ts

@@ -64,6 +64,11 @@ export function emptyKeys(held: { attrs?: AdfAttributes; content?: AdfNode[]; ma
   return keys
 }
 
+// A text node holding its text and marks alone: a format spells it as text, where anything more rides a carry.
+export function isPlainText(node: AdfNode): boolean {
+  return node.type === 'text' && node.attrs === undefined && node.content === undefined && node.marks?.length !== 0
+}
+
 export function identicalMark(left: AdfMark, right: AdfMark): boolean {
   return marksKey([left]) === marksKey([right])
 }

src/markdown/emit/adf-to-markdown.ts

@@ -1,7 +1,7 @@
 import type { AdfDocument, AdfNode } from '../../adf/document.ts'
 import type { BlockNodeModel } from '../../adf/block-nodes.ts'
 import type { Flavour } from '../plain-conventions.ts'
-import { adfDocumentFault, carriesOnly, nodeAttrs, nodeContent } from '../../adf/document.ts'
+import { adfDocumentFault, carriesOnly, isPlainText, nodeAttrs, nodeContent } from '../../adf/document.ts'
 import { alertMarker, foldedAlertMarker, leadingMarker, readAlertMarker, readTaskMarker, taskMarker } from '../plain-conventions.ts'
 import { blockDirectiveForm, documentSpelling, listBreakSpelling } from '../block-directive.ts'
 import { blockNodeModel, blockNodes } from '../../adf/block-nodes.ts'
@@ -278,7 +278,7 @@ function emitCodeDirective(node: AdfNode, model: BlockNodeModel, path: ConvertEr
 // The text each fence holds, or `undefined` where a child is no plain text node, which the carry holds instead.
 function fencedTexts(node: AdfNode, path: ConvertErrorPath): Result<string[] | undefined> {
   if (node.content === undefined) return success([''])
-  if (node.content.some((child) => child.type !== 'text' || child.attrs !== undefined || child.content !== undefined || child.marks !== undefined)) return success(undefined)
+  if (node.content.some((child) => !isPlainText(child) || child.marks !== undefined)) return success(undefined)
   const texts: string[] = []
   for (const [index, child] of node.content.entries()) {
     const childPath = [...path, 'content', index]

src/markdown/emit/inline-line.ts

@@ -6,7 +6,7 @@ import { assembleInlineLine, isSyntax, type InlineEscaping, type InlineSegment,
 import { carriedInline } from '../opaque-carry.ts'
 import { claimsLine, holdsNullCharacter, trimTrailingSpace } from '../commonmark/grammar.ts'
 import { commonMarkLink, linkHref, markSpelling, spellMarkAttributes } from '../mark-spellings.ts'
-import { emptyKeys, identicalMark, nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
+import { identicalMark, isPlainText, nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
 import { escapeUnbalanced, spellDestination } from '../commonmark/link-syntax.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { highlightDelimiter } from '../plain-conventions.ts'
@@ -268,9 +268,9 @@ function emitInlineDirective(node: AdfNode, model: InlineNodeModel, index: numbe
 }
 
 function emitText(node: AdfNode, context: InlineContext, index: number, path: ConvertErrorPath): Result<Emission> {
-  if (node.attrs !== undefined || emptyKeys(node).length > 0) return success({ carry: { first: index, last: index } })
-  if (typeof node.text !== 'string' || node.text === '') return failure('unsupported-node-shape', 'a text node holds text: this one has none', path)
   if (nodeContent(node).length > 0) return failure('unsupported-node-shape', 'a text node holds no content: this one holds some', path)
+  if (!isPlainText(node)) return success({ carry: { first: index, last: index } })
+  if (typeof node.text !== 'string' || node.text === '') return failure('unsupported-node-shape', 'a text node holds text: this one has none', path)
   if (/\r/.test(node.text)) return failure('unspellable-character', 'a text node holds a carriage return CommonMark rewrites', path)
   if (holdsNullCharacter(node.text)) return failure('unspellable-character', 'a text node holds a null character CommonMark replaces', path)
   const escaping: InlineEscaping = context.bracketed ? 'bracketed' : 'backslash'
@@ -323,10 +323,10 @@ function emitHighlight(nodes: readonly AdfNode[], depth: number, range: NodeRang
 function emitCodeSpan(nodes: readonly AdfNode[], depth: number, range: NodeRange, path: ConvertErrorPath): Result<Emission> {
   const spans: string[] = []
   for (const node of nodes) {
-    if (node.type !== 'text' || nodeMarks(node).length !== depth + 1 || node.attrs !== undefined || emptyKeys(node).length > 0) return success({ carry: range })
+    if (node.type === 'text' && nodeContent(node).length > 0) return failure('unsupported-node-shape', 'a text node holds no content: this one holds some', path)
+    if (!isPlainText(node) || nodeMarks(node).length !== depth + 1) return success({ carry: range })
     const { text } = node
     if (typeof text !== 'string' || text === '') return failure('unsupported-node-shape', 'a text node holds text: this one has none', path)
-    if (nodeContent(node).length > 0) return failure('unsupported-node-shape', 'a text node holds no content: this one holds some', path)
     if (/[\n\r]/.test(text)) return success({ carry: range })
     if (holdsNullCharacter(text)) return failure('unspellable-character', 'a code span holds a null character CommonMark replaces', path)
     const fence = '`'.repeat(longestBacktickRun(text) + 1)

src/markdown/parse/directive-nodes.ts

@@ -3,7 +3,7 @@ import type { BlockNodeModel } from '../../adf/block-nodes.ts'
 import type { ConvertFault } from '../../result.ts'
 import type { DirectiveAttributes, DirectiveValue } from '../directive-syntax.ts'
 import type { Elsewhere } from './directive-attributes.ts'
-import { attributeNestingMessage, nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
+import { attributeNestingMessage, isPlainText } from '../../adf/document.ts'
 import { attributeValue, directivePrefix, spellAttributeValue, unknownDirectiveFault } from '../directive-syntax.ts'
 import { blockArgument, blockDirectiveForm, marksAttribute, readMarkValues } from '../block-directive.ts'
 import { blockNodeModel } from '../../adf/block-nodes.ts'
@@ -95,7 +95,7 @@ function blockSpellingFault(name: string): ConvertFault | undefined {
 function slotText(content: readonly AdfNode[]): string | undefined {
   if (content.length === 0) return ''
   const only = content.length === 1 ? content[0] : undefined
-  if (only?.type !== 'text' || nodeMarks(only).length > 0 || Object.keys(nodeAttrs(only)).length > 0 || nodeContent(only).length > 0 || typeof only.text !== 'string') return undefined
+  if (only === undefined || !isPlainText(only) || only.marks !== undefined || typeof only.text !== 'string') return undefined
   return only.text
 }
 

src/markdown/text-break.ts

@@ -1,5 +1,5 @@
 import type { AdfNode } from '../adf/document.ts'
-import { identicalMarks, nodeMarks } from '../adf/document.ts'
+import { identicalMarks, isPlainText, nodeMarks } from '../adf/document.ts'
 import { spellInlineLeafDirective } from './directive-syntax.ts'
 
 export const textBreakName = 'textBreak'
@@ -8,9 +8,5 @@ export const textBreakSpelling = spellInlineLeafDirective(textBreakName, '')
 
 // Whether CommonMark reads the pair back as one text node, where neither rides the carry (spec/flavour.md, Inline nodes).
 export function readsAsOne(previous: AdfNode, node: AdfNode): boolean {
-  return spelledAsText(previous) && spelledAsText(node) && identicalMarks(nodeMarks(previous), nodeMarks(node))
-}
-
-function spelledAsText(node: AdfNode): boolean {
-  return node.type === 'text' && node.attrs === undefined && node.content === undefined && node.marks?.length !== 0
+  return isPlainText(previous) && isPlainText(node) && identicalMarks(nodeMarks(previous), nodeMarks(node))
 }