Answer the architecture pass: the empty {attrs}, the reserved fence and where the reader lives

src/markdown/directive-syntax.test.ts

@@ -49,7 +49,6 @@ test('reads the leaf and container forms, their argument and their attributes',
   assert.deepEqual(readDirectiveLine('::rule'), header(2, 'rule'))
   assert.deepEqual(readDirectiveLine('::rule  '), header(2, 'rule'))
   assert.deepEqual(readDirectiveLine('::taskItem TODO'), header(2, 'taskItem', 'TODO'))
-  assert.deepEqual(readDirectiveLine('::hardBreak {}'), header(2, 'hardBreak'))
   assert.deepEqual(readDirectiveLine('::media {id=a-1 type=file}'), header(2, 'media', undefined, ['id', 'a-1'], ['type', 'file']))
   assert.deepEqual(readDirectiveLine('::panel info {panelColor="#ff0000"} '), header(2, 'panel', 'info', ['panelColor', '#ff0000', '"#ff0000"']))
   assert.deepEqual(readDirectiveLine(':::panel info'), header(3, 'panel', 'info'))
@@ -70,6 +69,14 @@ test('names the {attrs} keys read out of the alphabetical order canonical form s
   assert.deepEqual(readDirectiveLine('::media {id=a-1 type=file}'), header(2, 'media', undefined, ['id', 'a-1'], ['type', 'file']))
 })
 
+test('spells an empty {attrs} only where the brace itself claims the directive', () => {
+  const omitted = 'an empty {attrs} is omitted unless the { itself claims the directive'
+  assert.equal(fault('::rule {}'), omitted)
+  assert.equal(fault(':::panel info {}'), omitted)
+  assert.equal(inline(':underline[a]{}'), omitted)
+  spans(':hardBreak{}', 'hardBreak', undefined)
+})
+
 test('names the directive line no spelling reads', () => {
   assert.equal(fault('::Panel'), 'a directive name reads [a-z][A-Za-z0-9]*')
   assert.equal(fault('::1panel'), 'a directive name reads [a-z][A-Za-z0-9]*')
@@ -77,7 +84,7 @@ test('names the directive line no spelling reads', () => {
   assert.equal(fault('::panel info extra'), 'a directive line reads a name, one bare argument and {attrs}, one space apart')
   assert.equal(fault('::panel{}'), 'a directive line reads a name, one bare argument and {attrs}, one space apart')
   assert.equal(fault('::panel info{}'), 'a directive line reads a name, one bare argument and {attrs}, one space apart')
-  assert.equal(fault('::panel {} x'), 'a directive line reads a name, one bare argument and {attrs}, one space apart')
+  assert.equal(fault('::panel {a=1} x'), 'a directive line reads a name, one bare argument and {attrs}, one space apart')
 })
 
 test('names the attributes no spelling reads', () => {
@@ -119,7 +126,6 @@ test('binds an inline directive as a unit, its content balancing brackets like l
   spans(':underline[a `b c]', 'underline', 'a `b c')
   spans(':underline[:status[x]{color=red}]', 'underline', ':status[x]{color=red}')
   spans(':status[x]{color=red style="bold "}', 'status', 'x', ['color', 'red'], ['style', 'bold ', '"bold "'])
-  assert.deepEqual(inline(':underline[a]{}(b)'), { attributes: attributes(), content: 'a', length: 15, name: 'underline' })
   assert.deepEqual(inline(':underline[a] {}'), { attributes: attributes(), content: 'a', length: 13, name: 'underline' })
   assert.deepEqual(inline(':text{text=" "} and more'), { attributes: attributes(['text', ' ', '" "']), content: undefined, length: 15, name: 'text' })
 })

src/markdown/directive-syntax.ts

@@ -37,6 +37,7 @@ const quotedEscapes = new RegExp(reservedSource, 'g')
 const rawReserved = new RegExp(reservedSource)
 const noAttributes: DirectiveAttributes = new Map()
 
+const emptyFault = 'an empty {attrs} is omitted unless the { itself claims the directive'
 const nameFault = 'a directive name reads [a-z][A-Za-z0-9]*'
 const orderFault = 'the {attrs} keys read in alphabetical order'
 const pairFault = 'an attribute reads key=value, the value bare or double-quoted'
@@ -136,6 +137,7 @@ function readDirectiveHeader(rest: string): Read<{ argument: string | undefined;
   if (rest.charAt(cursor) === ' ' && rest.charAt(cursor + 1) === '{') {
     const read = readAttributes(rest, cursor + 1)
     if (read.fault !== undefined) return { fault: read.fault }
+    if (read.value.attributes.size === 0) return { fault: malformedDirective(emptyFault) }
     attributes = read.value.attributes
     cursor += 1 + read.value.length
   }
@@ -161,6 +163,7 @@ function readNestedDirective(text: string, index: number, depth: number): Read<D
   if (text.charAt(cursor) === '{') {
     const read = readAttributes(text, cursor)
     if (read.fault !== undefined) return { fault: read.fault }
+    if (read.value.attributes.size === 0 && content !== undefined) return { fault: malformedDirective(emptyFault) }
     attributes = read.value.attributes
     cursor += read.value.length
   }

src/markdown/parse/directive-nodes.ts

@@ -12,7 +12,7 @@ import { marksAttribute, readMarkValues } from '../block-directive-marks.ts'
 
 export type BlockDirectiveNode = { contentModel: BlockDirective['contentModel']; node: AdfNode }
 
-type Elsewhere = { key: string; place: string }
+type Elsewhere = { key: string; slot: 'argument' | 'content' }
 
 export function readBlockDirectiveNode(
   name: string,
@@ -28,7 +28,7 @@ export function readBlockDirectiveNode(
   const argumentKey = blockArgument(name)
   const rest = new Map(attributes)
   rest.delete(marksAttribute)
-  const elsewhere = argumentKey === undefined ? undefined : { key: argumentKey, place: 'as the directive argument' }
+  const elsewhere: Elsewhere | undefined = argumentKey === undefined ? undefined : { key: argumentKey, slot: 'argument' }
   const attrs = readVocabulary(name, rest, directive.attributes, elsewhere, path)
   if (!attrs.ok) return attrs
   if (argument !== undefined) {
@@ -38,7 +38,7 @@ export function readBlockDirectiveNode(
   const spelled = attributes.get(marksAttribute)
   const marks: Result<AdfMark[] | undefined> = spelled === undefined ? success(undefined) : readMarks(name, spelled, path)
   if (!marks.ok) return marks
-  return success({ contentModel: directive.contentModel, node: directiveNode(name, attrs.value, marks.value) })
+  return success({ contentModel: directive.contentModel, node: namedNode(name, attrs.value, marks.value) })
 }
 
 export function readInlineDirectiveNode(span: DirectiveSpan, path: ConvertErrorPath): Result<AdfNode> {
@@ -49,10 +49,10 @@ export function readInlineDirectiveNode(span: DirectiveSpan, path: ConvertErrorP
     const message = slot === undefined ? `a ${span.name} takes no content` : `the content slot a ${span.name} spells its ${slot} attribute in is unsupported`
     return failure('unsupported-node-shape', message, path)
   }
-  const elsewhere = slot === undefined ? undefined : { key: slot, place: 'in the content slot' }
+  const elsewhere: Elsewhere | undefined = slot === undefined ? undefined : { key: slot, slot: 'content' }
   const attrs = readVocabulary(span.name, span.attributes, directive.attributes, elsewhere, path)
   if (!attrs.ok) return attrs
-  return success(directiveNode(span.name, attrs.value, undefined))
+  return success(namedNode(span.name, attrs.value, undefined))
 }
 
 function readVocabulary(
@@ -64,7 +64,10 @@ function readVocabulary(
 ): Result<AdfAttributes> {
   const attrs: AdfAttributes = {}
   for (const [key, spelled] of attributes) {
-    if (key === elsewhere?.key) return failure('unsupported-node-shape', `a ${type} spells its ${key} attribute ${elsewhere.place}`, path)
+    if (key === elsewhere?.key) {
+      const place = elsewhere.slot === 'argument' ? 'as the directive argument' : 'in the content slot'
+      return failure('unsupported-node-shape', `a ${type} spells its ${key} attribute ${place}`, path)
+    }
     const kind = Object.hasOwn(vocabulary, key) ? vocabulary[key] : undefined
     if (kind === undefined) return failure('unsupported-node-shape', `a ${type} holds no ${key} attribute`, path)
     const read = attributeValue(spelled.text, kind)
@@ -85,7 +88,7 @@ function readMarks(type: string, spelled: DirectiveValue, path: ConvertErrorPath
   return success(marks)
 }
 
-function directiveNode(type: string, attrs: AdfAttributes, marks: readonly AdfMark[] | undefined): AdfNode {
+function namedNode(type: string, attrs: AdfAttributes, marks: readonly AdfMark[] | undefined): AdfNode {
   const named = Object.keys(attrs).length === 0 ? { type } : { attrs, type }
   return marks === undefined ? named : { ...named, marks: [...marks] }
 }

src/markdown/parse/markdown-to-adf.test.ts

@@ -159,6 +159,8 @@ test('names the reserved carry name a block directive spells', () => {
   const reserved = 'malformed-directive: the name adf is reserved for the opaque carry, whose block form is the fence'
   assert.equal(content(markdownToAdf('::adf\n')), reserved)
   assert.equal(content(markdownToAdf(':::adf\nx\n:::\n')), reserved)
+  assert.equal(content(markdownToAdf('```adf\nx\n```\n')), 'malformed-directive: the info string adf is reserved for the opaque carry')
+  assert.deepEqual(content(markdownToAdf('```adfx\nx\n```\n')), [{ attrs: { language: 'adfx' }, content: [text('x')], type: 'codeBlock' }])
 })
 
 test('reads each attribute value as the type its section assigns', () => {

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

@@ -1,6 +1,7 @@
 import type { AdfDocument, AdfNode } from '../../adf/document.ts'
 import type { Block, DirectiveBlock } from './blocks.ts'
 import type { LinkDefinitions } from './inline-content.ts'
+import { carryName } from '../opaque-carry.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { largestNesting } from '../../nesting.ts'
 import { parseBlocks } from './blocks.ts'
@@ -32,7 +33,7 @@ function blockNode(block: Block, definitions: LinkDefinitions, path: ConvertErro
     case 'bulletList':
       return listNode({ type: 'bulletList' }, block.items, definitions, path, depth)
     case 'code':
-      return success(codeBlockNode(block.language, block.text))
+      return codeBlockNode(block.language, block.text, path)
     case 'directive':
       return directiveNode(block, definitions, path, depth)
     case 'fault':
@@ -92,9 +93,10 @@ function listNode(node: AdfNode, items: readonly Block[][], definitions: LinkDef
   return success({ ...node, content })
 }
 
-function codeBlockNode(language: string, text: string): AdfNode {
+function codeBlockNode(language: string, text: string, path: ConvertErrorPath): Result<AdfNode> {
+  if (language === carryName) return failure('malformed-directive', `the info string ${carryName} is reserved for the opaque carry`, path)
   const node: AdfNode = language === '' ? { type: 'codeBlock' } : { attrs: { language }, type: 'codeBlock' }
-  return text === '' ? node : { ...node, content: [{ text, type: 'text' }] }
+  return success(text === '' ? node : { ...node, content: [{ text, type: 'text' }] })
 }
 
 // spec/flavour.md, The CommonMark image: only a plain paragraph gives an image the block it needs.