Make markdownToAdf(adfToMarkdown(doc)) deep-equal doc: textBreak, empty keys, -0, typed carry fences, code blocks of several text nodes

browser-tests/convert-corpus.js

@@ -1,16 +1,19 @@
 try {
   const { adfToMarkdown, isAdfDocument, markdownToAdf } = await import('/dist/index.js')
+  const { serializeCanonicalJson } = await import('/dist/canonical-json.js')
+  // WebDriver's JSON reads -0 back as 0, so a document crosses as its canonical spelling.
+  const spelled = (result) => (result.ok ? { ok: true, value: `${serializeCanonicalJson(result.value, 'two-space')}\n` } : result)
   window.convertCorpus = (corpus) => ({
     errors: corpus.errors.map(({ markdown, name }) => ({ name, parsed: markdownToAdf(markdown) })),
-    normalization: corpus.normalization.map(({ markdown, name }) => ({ name, parsed: markdownToAdf(markdown) })),
+    normalization: corpus.normalization.map(({ markdown, name }) => ({ name, parsed: spelled(markdownToAdf(markdown)) })),
     realPayloads: corpus.realPayloads.map(({ json, name }) => {
       const adf = JSON.parse(json)
       const emitted = adfToMarkdown(adf)
-      return { emitted, isDocument: isAdfDocument(adf), name, parsed: emitted.ok ? markdownToAdf(emitted.value) : undefined }
+      return { emitted, isDocument: isAdfDocument(adf), name, parsed: emitted.ok ? spelled(markdownToAdf(emitted.value)) : undefined }
     }),
     roundTrip: corpus.roundTrip.map(({ json, markdown, name }) => {
       const adf = JSON.parse(json)
-      return { emitted: adfToMarkdown(adf), isDocument: isAdfDocument(adf), name, parsed: markdownToAdf(markdown) }
+      return { emitted: adfToMarkdown(adf), isDocument: isAdfDocument(adf), name, parsed: spelled(markdownToAdf(markdown)) }
     }),
   })
 } catch (cause) {

browser-tests/run.js

@@ -2,7 +2,6 @@ import assert from 'node:assert/strict'
 import { createServer } from 'node:http'
 import { extname, join } from 'node:path'
 import { readFileSync, readdirSync } from 'node:fs'
-import { toEditorNormal } from '../dist/adf/editor-normal.js'
 
 const contentTypes = { '.html': 'text/html; charset=utf-8', '.js': 'text/javascript' }
 const driver = 'http://127.0.0.1:4444'
@@ -107,7 +106,7 @@ for (const [index, { json, markdown, name }] of corpus.roundTrip.entries()) {
     assert.ok(result.emitted.ok, `it did not emit — ${refusal(result.emitted)}`)
     assert.equal(result.emitted.value, markdown)
     assert.ok(result.parsed.ok, `it did not parse — ${refusal(result.parsed)}`)
-    assert.deepEqual(toEditorNormal(result.parsed.value), JSON.parse(json))
+    assert.equal(result.parsed.value, json)
   })
 }
 
@@ -115,7 +114,7 @@ for (const [index, { name }] of corpus.normalization.entries()) {
   const result = results.normalization[index]
   checking(name, result, () => {
     assert.ok(result.parsed.ok, `it did not parse — ${refusal(result.parsed)}`)
-    assert.deepEqual(toEditorNormal(result.parsed.value), JSON.parse(fixture(name, '.json')))
+    assert.equal(result.parsed.value, fixture(name, '.json'))
   })
 }
 
@@ -125,7 +124,7 @@ for (const [index, { json, name }] of corpus.realPayloads.entries()) {
     assert.ok(result.isDocument, `${name}.json is no ADF document`)
     assert.ok(result.emitted.ok, `it did not emit — ${refusal(result.emitted)}`)
     assert.ok(result.parsed.ok, `it did not parse back — ${refusal(result.parsed)}`)
-    assert.deepEqual(toEditorNormal(result.parsed.value), JSON.parse(json))
+    assert.equal(result.parsed.value, json)
   })
 }
 

corpus/errors/carry-fence-type-spellable.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/carry-fence-type-spellable.md

@@ -0,0 +1,5 @@
+```adf:
+{
+  "type": "blockCard"
+}
+```

corpus/errors/carry-fence-type.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/carry-fence-type.md

@@ -0,0 +1,5 @@
+```adf:blockCard
+{
+  "type": "blockCard"
+}
+```

corpus/errors/carry-invalid-json.md

@@ -1,3 +1,3 @@
-```carry
+```adf:blockCard
-{"type":
+{"attrs":
 ```

corpus/errors/code-block-fence-languages.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/code-block-fence-languages.md

@@ -0,0 +1,8 @@
+!adf:codeBlock
+```js
+a
+```
+```ts
+b
+```
+!adf:/codeBlock

corpus/errors/document-directive-bare.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/document-directive-bare.md

@@ -0,0 +1 @@
+!adf:doc

corpus/errors/document-directive-misplaced.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/document-directive-misplaced.md

@@ -0,0 +1,3 @@
+!adf:doc {content=none}
+
+Text.

corpus/errors/empty-attrs-with-attributes.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/empty-attrs-with-attributes.md

@@ -0,0 +1,3 @@
+!adf:panel info {attrs=empty}
+Text.
+!adf:/panel

corpus/errors/empty-content-with-body.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/empty-content-with-body.md

@@ -0,0 +1,3 @@
+!adf:paragraph {content=empty}
+Text.
+!adf:/paragraph

corpus/errors/empty-key-value.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/empty-key-value.md

@@ -0,0 +1,3 @@
+!adf:paragraph {attrs=none}
+Text.
+!adf:/paragraph

corpus/errors/empty-marks-wrapped.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/empty-marks-wrapped.md

@@ -0,0 +1 @@
+**!adf:date{marks=empty}**

corpus/errors/text-break-attributes.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/text-break-attributes.md

@@ -0,0 +1 @@
+a!adf:textBreak{x=y}b

corpus/errors/text-break-content.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/text-break-content.md

@@ -0,0 +1 @@
+a!adf:textBreak[x]b

corpus/errors/text-break-marks-differ.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/text-break-marks-differ.md

@@ -0,0 +1 @@
+**a**!adf:textBreak{}b

corpus/errors/text-break-misplaced.error

@@ -0,0 +1 @@
+unsupported-node-shape

corpus/errors/text-break-misplaced.md

@@ -0,0 +1 @@
+!adf:textBreak{}Hello

corpus/round-trip/block-nodes/code-block-carry.json

@@ -14,7 +14,19 @@
     },
     {
       "attrs": {
-        "language": "carry"
+        "language": "adf:blockCard"
+      },
+      "content": [
+        {
+          "text": "{\n  \"attrs\": {}\n}",
+          "type": "text"
+        }
+      ],
+      "type": "codeBlock"
+    },
+    {
+      "attrs": {
+        "language": "adf:"
       },
       "content": [
         {

corpus/round-trip/block-nodes/code-block-carry.md

@@ -1,12 +1,18 @@
-!adf:codeBlock {language=carry}
+```carry
-```
 {
   "type": "blockCard"
 }
 ```
+
+!adf:codeBlock {language="adf:blockCard"}
+```
+{
+  "attrs": {}
+}
+```
 !adf:/codeBlock
 
-!adf:codeBlock {language=carry}
+!adf:codeBlock {language="adf:"}
 ````
 ```
 ````

corpus/round-trip/block-nodes/code-block-text-nodes.json

@@ -0,0 +1,56 @@
+{
+  "content": [
+    {
+      "attrs": {
+        "language": "js"
+      },
+      "content": [
+        {
+          "text": "const a = 1\n",
+          "type": "text"
+        },
+        {
+          "text": "const b = 2",
+          "type": "text"
+        }
+      ],
+      "type": "codeBlock"
+    },
+    {
+      "content": [
+        {
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "text": "```",
+          "type": "text"
+        },
+        {
+          "text": "\n",
+          "type": "text"
+        }
+      ],
+      "type": "codeBlock"
+    },
+    {
+      "attrs": {
+        "language": "has`tick",
+        "wrap": true
+      },
+      "content": [
+        {
+          "text": "x",
+          "type": "text"
+        },
+        {
+          "text": " y ",
+          "type": "text"
+        }
+      ],
+      "type": "codeBlock"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/block-nodes/code-block-text-nodes.md

@@ -0,0 +1,31 @@
+!adf:codeBlock
+```js
+const a = 1
+
+```
+```js
+const b = 2
+```
+!adf:/codeBlock
+
+!adf:codeBlock
+```
+a
+```
+````
+```
+````
+```
+
+
+```
+!adf:/codeBlock
+
+!adf:codeBlock {language="has\u0060tick" wrap=true}
+```
+x
+```
+```
+ y 
+```
+!adf:/codeBlock

corpus/round-trip/block-nodes/document-without-content.json

@@ -0,0 +1,4 @@
+{
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/block-nodes/document-without-content.md

@@ -0,0 +1 @@
+!adf:doc {content=none}

corpus/round-trip/block-nodes/empty-keys.json

@@ -0,0 +1,89 @@
+{
+  "content": [
+    {
+      "content": [],
+      "type": "paragraph"
+    },
+    {
+      "attrs": {},
+      "content": [
+        {
+          "text": "Plain words.",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [],
+      "type": "rule"
+    },
+    {
+      "attrs": {
+        "level": 2
+      },
+      "content": [
+        {
+          "text": "Title",
+          "type": "text"
+        }
+      ],
+      "marks": [],
+      "type": "heading"
+    },
+    {
+      "attrs": {
+        "panelType": "info"
+      },
+      "content": [],
+      "type": "panel"
+    },
+    {
+      "content": [
+        {
+          "attrs": {},
+          "content": [
+            {
+              "content": [
+                {
+                  "text": "Item",
+                  "type": "text"
+                }
+              ],
+              "type": "paragraph"
+            }
+          ],
+          "type": "listItem"
+        },
+        {
+          "content": [
+            {
+              "content": [
+                {
+                  "text": "Next",
+                  "type": "text"
+                }
+              ],
+              "type": "paragraph"
+            }
+          ],
+          "type": "listItem"
+        }
+      ],
+      "type": "bulletList"
+    },
+    {
+      "content": [],
+      "type": "codeBlock"
+    },
+    {
+      "attrs": {
+        "language": "js"
+      },
+      "marks": [],
+      "type": "codeBlock"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/block-nodes/empty-keys.md

@@ -0,0 +1,32 @@
+!adf:paragraph {content=empty}
+!adf:/paragraph
+
+!adf:paragraph {attrs=empty}
+Plain words.
+!adf:/paragraph
+
+!adf:rule {content=empty}
+
+!adf:heading {level=2 marks=empty}
+Title
+!adf:/heading
+
+!adf:panel info {content=empty}
+!adf:/panel
+
+!adf:bulletList
+!adf:listItem {attrs=empty}
+Item
+!adf:/listItem
+!adf:listItem
+Next
+!adf:/listItem
+!adf:/bulletList
+
+!adf:codeBlock {content=empty}
+!adf:/codeBlock
+
+!adf:codeBlock {marks=empty}
+```js
+```
+!adf:/codeBlock

corpus/round-trip/combinations/carry-attributes.md

@@ -1,4 +1,4 @@
-```carry
+```adf:panel
 {
   "attrs": {
     "rounded": true
@@ -13,12 +13,11 @@
       ],
       "type": "paragraph"
     }
-  ],
+  ]
-  "type": "panel"
 }
 ```
 
-```carry
+```adf:panel
 {
   "attrs": {
     "panelType": "extra info"
@@ -33,8 +32,7 @@
       ],
       "type": "paragraph"
     }
-  ],
+  ]
-  "type": "panel"
 }
 ```
 

corpus/round-trip/combinations/negative-zero.json

@@ -0,0 +1,83 @@
+{
+  "content": [
+    {
+      "attrs": {
+        "order": -0
+      },
+      "content": [
+        {
+          "content": [
+            {
+              "content": [
+                {
+                  "text": "First",
+                  "type": "text"
+                }
+              ],
+              "type": "paragraph"
+            }
+          ],
+          "type": "listItem"
+        }
+      ],
+      "type": "orderedList"
+    },
+    {
+      "attrs": {
+        "level": -0
+      },
+      "content": [
+        {
+          "text": "Title",
+          "type": "text"
+        }
+      ],
+      "type": "heading"
+    },
+    {
+      "attrs": {
+        "extensionKey": "toc",
+        "extensionType": "com.atlassian.confluence.macro.core",
+        "parameters": {
+          "maxLevel": -0
+        }
+      },
+      "type": "extension"
+    },
+    {
+      "content": [
+        {
+          "attrs": {
+            "data": [
+              -0
+            ],
+            "url": "https://example.com/"
+          },
+          "type": "inlineCard"
+        },
+        {
+          "marks": [
+            {
+              "attrs": {
+                "color": "#000000",
+                "size": -0
+              },
+              "type": "border"
+            }
+          ],
+          "text": "x",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "attrs": {
+        "x": -0
+      },
+      "type": "blockCard"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/combinations/negative-zero.md

@@ -0,0 +1,21 @@
+!adf:orderedList {order=-0}
+!adf:listItem
+First
+!adf:/listItem
+!adf:/orderedList
+
+!adf:heading {level=-0}
+Title
+!adf:/heading
+
+!adf:extension {extensionKey=toc extensionType="com.atlassian.confluence.macro.core" parameters="{\"maxLevel\":-0}"}
+
+!adf:inlineCard{data="[-0]" url="https://example.com/"}!adf:border[x]{color="#000000" size=-0}
+
+```adf:blockCard
+{
+  "attrs": {
+    "x": -0
+  }
+}
+```

corpus/round-trip/commonmark-subset/document-empty.json

@@ -1,4 +1,5 @@
 {
+  "content": [],
   "type": "doc",
   "version": 1
 }

corpus/round-trip/inline-nodes/empty-keys.json

@@ -0,0 +1,98 @@
+{
+  "content": [
+    {
+      "content": [
+        {
+          "attrs": {},
+          "type": "date"
+        },
+        {
+          "text": " ",
+          "type": "text"
+        },
+        {
+          "content": [],
+          "type": "date"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "marks": [],
+          "type": "hardBreak"
+        },
+        {
+          "text": "b",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "attrs": {
+            "id": "x",
+            "text": "@M"
+          },
+          "content": [],
+          "type": "mention"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "text": "bare",
+          "type": "text"
+        },
+        {
+          "marks": [],
+          "text": "marked",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "attrs": {},
+              "type": "em"
+            }
+          ],
+          "text": "x",
+          "type": "text"
+        },
+        {
+          "text": " and ",
+          "type": "text"
+        },
+        {
+          "attrs": {
+            "shortName": ":a:"
+          },
+          "marks": [
+            {
+              "attrs": {},
+              "type": "strong"
+            }
+          ],
+          "type": "emoji"
+        }
+      ],
+      "type": "paragraph"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/inline-nodes/empty-keys.md

@@ -0,0 +1,9 @@
+!adf:date{attrs=empty} !adf:date{content=empty}
+
+a!adf:hardBreak{marks=empty}b
+
+!adf:mention[@M]{content=empty id=x}
+
+bare!adf:carry{json="{\"marks\":[],\"text\":\"marked\",\"type\":\"text\"}"}
+
+!adf:carry{json="{\"marks\":[{\"attrs\":{},\"type\":\"em\"}],\"text\":\"x\",\"type\":\"text\"}"} and !adf:carry{json="{\"attrs\":{\"shortName\":\":a:\"},\"marks\":[{\"attrs\":{},\"type\":\"strong\"}],\"type\":\"emoji\"}"}

corpus/round-trip/inline-nodes/text-break.json

@@ -0,0 +1,154 @@
+{
+  "content": [
+    {
+      "content": [
+        {
+          "text": "Hello, ",
+          "type": "text"
+        },
+        {
+          "text": "world",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "strong"
+            }
+          ],
+          "text": "Hello, ",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "type": "strong"
+            }
+          ],
+          "text": "world",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "code"
+            }
+          ],
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "type": "code"
+            }
+          ],
+          "text": "b",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "attrs": {
+                "href": "https://example.com/"
+              },
+              "type": "link"
+            }
+          ],
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "attrs": {
+                "href": "https://example.com/"
+              },
+              "type": "link"
+            }
+          ],
+          "text": "b",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "text": "Line\n",
+          "type": "text"
+        },
+        {
+          "text": "next",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "underline"
+            }
+          ],
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "type": "underline"
+            }
+          ],
+          "text": "b",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "attrs": {},
+              "type": "underline"
+            }
+          ],
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "type": "underline"
+            }
+          ],
+          "text": "b",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/inline-nodes/text-break.md

@@ -0,0 +1,13 @@
+Hello, !adf:textBreak{}world
+
+**Hello, !adf:textBreak{}world**
+
+`a`!adf:textBreak{}`b`
+
+[a!adf:textBreak{}b](https://example.com/)
+
+Line!adf:text{text="\n"}!adf:textBreak{}next
+
+!adf:underline[a!adf:textBreak{}b]
+
+!adf:underline[a]{attrs=empty}!adf:underline[b]

corpus/round-trip/opaque-carry/carry-in-wrappers.md

@@ -1,17 +1,15 @@
-> ```carry
+> ```adf:blockCard
 > {
 >   "attrs": {
 >     "url": "https://example.com/quoted"
->   },
+>   }
->   "type": "blockCard"
 > }
 > ```
 
-- ```carry
+- ```adf:blockCard
   {
     "attrs": {
       "url": "https://example.com/listed"
-    },
+    }
-    "type": "blockCard"
   }
   ```

corpus/round-trip/opaque-carry/code-block-children.json

@@ -0,0 +1,35 @@
+{
+  "content": [
+    {
+      "attrs": {
+        "language": "js"
+      },
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "strong"
+            }
+          ],
+          "text": "const a = 1",
+          "type": "text"
+        }
+      ],
+      "type": "codeBlock"
+    },
+    {
+      "content": [
+        {
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "type": "hardBreak"
+        }
+      ],
+      "type": "codeBlock"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/opaque-carry/code-block-children.md

@@ -0,0 +1,32 @@
+```adf:codeBlock
+{
+  "attrs": {
+    "language": "js"
+  },
+  "content": [
+    {
+      "marks": [
+        {
+          "type": "strong"
+        }
+      ],
+      "text": "const a = 1",
+      "type": "text"
+    }
+  ]
+}
+```
+
+```adf:codeBlock
+{
+  "content": [
+    {
+      "text": "a",
+      "type": "text"
+    },
+    {
+      "type": "hardBreak"
+    }
+  ]
+}
+```

corpus/round-trip/opaque-carry/unknown-block.md

@@ -1,23 +1,21 @@
-```carry
+```adf:blockCard
 {
   "attrs": {
     "url": "https://example.com/roadmap"
-  },
+  }
-  "type": "blockCard"
 }
 ```
 
 !adf:panel info
 The card below has no spelling yet.
 
-```carry
+```adf:embedCard
 {
   "attrs": {
     "layout": "wide",
     "url": "https://example.com/board",
     "width": 100
-  },
+  }
-  "type": "embedCard"
 }
 ```
 !adf:/panel

corpus/round-trip/opaque-carry/unknown-type-spelling.json

@@ -0,0 +1,21 @@
+{
+  "content": [
+    {
+      "attrs": {
+        "url": "https://example.com/"
+      },
+      "type": "has`tick"
+    },
+    {
+      "type": ""
+    },
+    {
+      "type": " padded"
+    },
+    {
+      "type": "two words"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/opaque-carry/unknown-type-spelling.md

@@ -0,0 +1,24 @@
+```adf:
+{
+  "attrs": {
+    "url": "https://example.com/"
+  },
+  "type": "has`tick"
+}
+```
+
+```adf:
+{
+  "type": ""
+}
+```
+
+```adf:
+{
+  "type": " padded"
+}
+```
+
+```adf:two words
+{}
+```

src/adf/document.ts

@@ -1,6 +1,7 @@
 import type { ConvertFault } from '../result.ts'
 import { isJsonValue, overNested, type JsonValue } from '../json-value.ts'
 import { largestNesting } from '../nesting.ts'
+import { serializeCanonicalJson } from '../canonical-json.ts'
 
 export type AdfAttributes = { [key: string]: JsonValue }
 
@@ -17,6 +18,8 @@ export type AdfNode = {
   type: string
 }
 
+export type EmptyKey = 'attrs' | 'content' | 'marks'
+
 export type AdfDocument = {
   content?: AdfNode[]
   type: 'doc'
@@ -49,10 +52,26 @@ export function attributeNestingMessage(key: string, type: string): string {
 }
 
 export function carriesOnly(node: AdfNode, attributes: readonly string[]): boolean {
-  if (nodeMarks(node).length > 0 || node.text !== undefined) return false
+  if (nodeMarks(node).length > 0 || node.text !== undefined || emptyKeys(node).length > 0) return false
   return holdsOnly(nodeAttrs(node), attributes)
 }
 
+export function emptyKeys(held: { attrs?: AdfAttributes; content?: AdfNode[]; marks?: AdfMark[] }): EmptyKey[] {
+  const keys: EmptyKey[] = []
+  if (held.attrs !== undefined && Object.keys(held.attrs).length === 0) keys.push('attrs')
+  if (held.content?.length === 0) keys.push('content')
+  if (held.marks?.length === 0) keys.push('marks')
+  return keys
+}
+
+export function identicalMark(left: AdfMark, right: AdfMark): boolean {
+  return marksKey([left]) === marksKey([right])
+}
+
+export function identicalMarks(left: AdfNode, right: AdfNode): boolean {
+  return marksKey(nodeMarks(left)) === marksKey(nodeMarks(right))
+}
+
 // Depth is the walks' business, not the shape's: the guard waves a deep document through as blocks and marks do.
 export function isAdfDocument(value: unknown): value is AdfDocument {
   const fault = adfDocumentFault(value)
@@ -99,6 +118,13 @@ function isNodeArray(value: readonly unknown[]): value is readonly AdfNode[] {
   return true
 }
 
+function marksKey(marks: readonly AdfMark[]): string {
+  return serializeCanonicalJson(
+    marks.map((mark) => (mark.attrs === undefined ? [mark.type] : [mark.type, mark.attrs])),
+    'compact',
+  )
+}
+
 function nestingFault(nodes: readonly AdfNode[]): ConvertFault | undefined {
   const pending: AdfNode[] = [...nodes]
   while (pending.length > 0) {

src/adf/editor-normal.ts

@@ -77,7 +77,7 @@ function mergesText(node: AdfNode): boolean {
   return node.type === 'text' && Object.keys(nodeAttrs(node)).length === 0
 }
 
-export function sameMarks(previous: AdfNode, node: AdfNode): boolean {
+function sameMarks(previous: AdfNode, node: AdfNode): boolean {
   return marksKey(nodeMarks(previous)) === marksKey(nodeMarks(node))
 }
 
@@ -86,5 +86,5 @@ function marksKey(marks: readonly AdfMark[]): string {
 }
 
 function markKey(mark: AdfMark): string {
-  return `${mark.type} ${serializeCanonicalJson(nodeAttrs(mark), 'compact')}`
+  return `${mark.type} ${serializeCanonicalJson(normalAttributes(nodeAttrs(mark)) ?? {}, 'compact')}`
 }

src/canonical-json.ts

@@ -18,7 +18,7 @@ export function serializeCanonicalJson(value: JsonValue, spelling: JsonSpelling)
     const { depth, value: held } = next
     if (Array.isArray(held)) schedule(pending, '[', held.map((item) => ({ label: '', value: item })), ']', indent, depth)
     else if (held !== null && typeof held === 'object') schedule(pending, '{', objectMembers(held, indent), '}', indent, depth)
-    else text.push(JSON.stringify(held))
+    else text.push(Object.is(held, -0) ? '-0' : JSON.stringify(held))
   }
   return text.join('')
 }

src/conformance/adf-property.test.ts

@@ -8,7 +8,6 @@ import { adfToMarkdown } from '../markdown/emit/adf-to-markdown.ts'
 import { adfToPlainMarkdown, reduceToPlain } from '../markdown/emit/plain-reduction.ts'
 import { directivePrefix } from '../markdown/directive-syntax.ts'
 import { markdownToAdf, plainMarkdownToAdf } from '../markdown/parse/markdown-to-adf.ts'
-import { toEditorNormal } from '../adf/editor-normal.ts'
 
 const gateRuns = 1600
 const renamedPrefix = '!adg:'
@@ -41,7 +40,7 @@ test('a generated document refuses to emit, or its markdown reads back to it', {
       if (!emitted.ok) return
       const read = markdownToAdf(emitted.value)
       assert.ok(read.ok, read.ok ? '' : `${read.error.code}: ${read.error.message} — reading ${JSON.stringify(emitted.value)}`)
-      assert.deepEqual(toEditorNormal(read.value), document, `reading ${JSON.stringify(emitted.value)}`)
+      assert.deepEqual(read.value, document, `reading ${JSON.stringify(emitted.value)}`)
     }),
     propertyRuns(gateRuns),
   )

src/conformance/corpus.test.ts

@@ -9,7 +9,6 @@ import { isAdfDocument } from '../adf/document.ts'
 import { isJsonValue } from '../json-value.ts'
 import { markdownToAdf } from '../markdown/parse/markdown-to-adf.ts'
 import { serializeCanonicalJson } from '../canonical-json.ts'
-import { toEditorNormal } from '../adf/editor-normal.ts'
 
 const corpusRoot = join(dirname(fileURLToPath(import.meta.url)), '..', '..', 'corpus')
 const errorsRoot = join(corpusRoot, 'errors')
@@ -97,7 +96,7 @@ for (const directory of roundTripDirectories) {
       assert.ok(isAdfDocument(expected), `${name}.json is not an ADF document`)
       const result = markdownToAdf(readFileSync(join(roundTripRoot, directory, `${name}.md`), 'utf8'))
       assert.ok(result.ok, result.ok ? '' : `${result.error.code}: ${result.error.message}`)
-      assert.deepEqual(toEditorNormal(result.value), expected)
+      assert.deepEqual(result.value, expected)
     })
   }
 }
@@ -125,12 +124,12 @@ for (const name of pairedNames(normalizationRoot, '.md', '.json')) {
     assert.ok(isAdfDocument(expected), `${name}.json is not an ADF document`)
     const result = markdownToAdf(readFileSync(join(normalizationRoot, `${name}.md`), 'utf8'))
     assert.ok(result.ok, result.ok ? '' : `${result.error.code}: ${result.error.message}`)
-    assert.deepEqual(toEditorNormal(result.value), expected)
+    assert.deepEqual(result.value, expected)
     const emitted = adfToMarkdown(result.value)
     assert.ok(emitted.ok, emitted.ok ? '' : `${emitted.error.code}: ${emitted.error.message}`)
     const again = markdownToAdf(emitted.value)
     assert.ok(again.ok, again.ok ? '' : `${again.error.code}: ${again.error.message}`)
-    assert.deepEqual(toEditorNormal(again.value), expected)
+    assert.deepEqual(again.value, expected)
   })
 }
 
@@ -146,7 +145,7 @@ for (const name of names(realPayloadsRoot, '.json')) {
     assert.ok(emitted.ok, emitted.ok ? '' : `${emitted.error.code}: ${emitted.error.message}`)
     const parsed = markdownToAdf(emitted.value)
     assert.ok(parsed.ok, parsed.ok ? '' : `${parsed.error.code}: ${parsed.error.message}`)
-    assert.deepEqual(toEditorNormal(parsed.value), payload)
+    assert.deepEqual(parsed.value, payload)
   })
 }
 

src/conformance/markdown-property.test.ts

@@ -31,7 +31,6 @@ import { markdownToAdf } from '../markdown/parse/markdown-to-adf.ts'
 import { nodeContent, nodeMarks } from '../adf/document.ts'
 import { serializeCanonicalJson } from '../canonical-json.ts'
 import { textDirectiveName } from '../markdown/text-directive.ts'
-import { toEditorNormal } from '../adf/editor-normal.ts'
 import { vocabularyPairs } from '../adf/attribute-vocabulary.ts'
 
 type Choice = { arbitrary: Arbitrary<string>; hostile?: true; weight: number }
@@ -433,7 +432,7 @@ test('generated markdown refuses, or what it parses to refuses to emit, or its s
       if (holdsDirectiveShape(parsed.value)) directiveShaped += 1
       const read = markdownToAdf(emitted.value)
       assert.ok(read.ok, read.ok ? '' : `${read.error.code}: ${read.error.message} — reading ${JSON.stringify(emitted.value)}`)
-      assert.deepEqual(toEditorNormal(read.value), toEditorNormal(parsed.value), `reading ${JSON.stringify(emitted.value)}`)
+      assert.deepEqual(read.value, parsed.value, `reading ${JSON.stringify(emitted.value)}`)
       const respelled = adfToMarkdown(read.value)
       assert.ok(respelled.ok, respelled.ok ? '' : `${respelled.error.code}: ${respelled.error.message} — spelling ${JSON.stringify(emitted.value)} again`)
       assert.equal(respelled.value, emitted.value)

src/conformance/property-harness.ts

@@ -11,7 +11,7 @@ import { blockNodes } from '../adf/block-nodes.ts'
 import { directivePrefix } from '../markdown/directive-syntax.ts'
 import { inlineNodes } from '../adf/inline-nodes.ts'
 import { markAttributes } from '../adf/mark-attributes.ts'
-import { toEditorNormal } from '../adf/editor-normal.ts'
+import { mergeAdjacentText } from '../adf/editor-normal.ts'
 
 type Positions = { block: AdfNode; inline: AdfNode }
 
@@ -36,7 +36,11 @@ export function textOf(minLength: number): Arbitrary<string> {
 
 const text = textOf(1)
 const unknownType = fc.oneof(fc.stringMatching(/^[a-z][A-Za-z0-9]{0,7}$/), text).filter((type) => !spelledTypes.has(type))
-const numberValue = fc.oneof({ arbitrary: fc.integer({ max: 10, min: -1 }), weight: 3 }, { arbitrary: fc.double({ noDefaultInfinity: true, noNaN: true }), weight: 1 })
+const numberValue = fc.oneof(
+  { arbitrary: fc.integer({ max: 10, min: -1 }), weight: 6 },
+  { arbitrary: fc.double({ noDefaultInfinity: true, noNaN: true }), weight: 2 },
+  { arbitrary: fc.constant(-0), weight: 1 },
+)
 
 // V8's JSON.parse returns a wrong key after parsing a key holding an escaped backslash (https://issues.chromium.org/issues/521080746); Bun is unaffected.
 const keyPiece = fc
@@ -73,19 +77,37 @@ function heldAttributes(held: Readonly<Record<string, JsonValue | undefined>>):
   return attrs
 }
 
+// An empty attrs, content or marks key, and adjacent text a reader would merge, stay occasional: each takes a spelling outside CommonMark.
+// The copy gives fast-check's null-prototype records the prototype a parsed node has.
+function occasionallyEmpty<T extends AdfMark | AdfNode>(arbitrary: Arbitrary<T>): Arbitrary<T> {
+  return fc.tuple(arbitrary, fc.nat({ max: 9 })).map(([held, roll]) => (roll === 0 ? { ...held } : withoutEmptyKeys(held)))
+}
+
+function withoutEmptyKeys<T extends AdfMark | AdfNode>(held: T): T {
+  const kept = { ...held }
+  if (kept.attrs !== undefined && Object.keys(kept.attrs).length === 0) delete kept.attrs
+  if ('content' in kept && kept.content?.length === 0) delete kept.content
+  if ('marks' in kept && kept.marks?.length === 0) delete kept.marks
+  return kept
+}
+
+function occasionallyApart(arbitrary: Arbitrary<AdfNode[]>): Arbitrary<AdfNode[]> {
+  return fc.tuple(arbitrary, fc.nat({ max: 5 })).map(([nodes, roll]) => (roll === 0 ? nodes : mergeAdjacentText(nodes)))
+}
+
 function pipeTable({ body, header }: { body: AdfNode[][]; header: AdfNode[] }): AdfNode {
   const rows = [header, ...body.map((cells) => header.map((_, index) => cells[index] ?? emptyCell))]
   return { content: rows.map((content): AdfNode => ({ content, type: 'tableRow' })), type: 'table' }
 }
 
-const mark: Arbitrary<AdfMark> = fc.oneof(
+const mark: Arbitrary<AdfMark> = occasionallyEmpty(fc.oneof(
   { arbitrary: fc.oneof(...Object.entries(markAttributes).map(([type, vocabulary]) => attributes(vocabulary).map((attrs) => ({ attrs, type })))), weight: 9 },
   { arbitrary: attributes({ color: 'string' }).map((attrs) => ({ attrs, type: 'backgroundColor' })), weight: 2 },
   { arbitrary: fc.record({ attrs: fc.dictionary(jsonKey, jsonValue, { maxKeys: 2, noNullPrototype: true }), type: unknownType }), weight: 1 },
-)
+))
 const marks = fc.uniqueArray(mark, { maxLength: 3, selector: (held) => held.type })
 
-const textNode = fc.record({ marks, text }).map((held): AdfNode => ({ ...held, type: 'text' }))
+const textNode = occasionallyEmpty(fc.record({ marks, text }).map((held): AdfNode => ({ ...held, type: 'text' })))
 
 const backtickRunNode = fc
   .record({ marks: fc.oneof(fc.constant<AdfMark[]>([]), fc.constant<AdfMark[]>([{ type: 'code' }]), marks), text: fc.string({ maxLength: 6, minLength: 1, unit: fc.constantFrom('`', '``', ' ', 'a') }) })
@@ -96,7 +118,7 @@ const autolinkTextNode = fc
   .map(({ href, marks: held }): AdfNode => ({ marks: [...held.filter((outer) => outer.type !== 'link'), { attrs: { href }, type: 'link' }], text: href, type: 'text' }))
 
 const inlineArbitraries = Object.entries(inlineNodes).map(([type, model]) =>
-  fc.record({ attrs: attributes(model.attributes), marks }).map((held): AdfNode => ({ ...held, type })),
+  occasionallyEmpty(fc.record({ attrs: attributes(model.attributes), marks }).map((held): AdfNode => ({ ...held, type }))),
 )
 
 function weighted(arbitraries: readonly Arbitrary<AdfNode>[], weight: number): { arbitrary: Arbitrary<AdfNode>; weight: number }[] {
@@ -105,10 +127,10 @@ function weighted(arbitraries: readonly Arbitrary<AdfNode>[], weight: number): {
 
 const positions = fc.letrec<Positions>((tie) => {
   const blockContent = fc.array(tie('block'), { depthIdentifier, maxLength: 3 })
-  const inlineContent = fc.array(tie('inline'), { depthIdentifier, maxLength: 4 })
+  const inlineContent = occasionallyApart(fc.array(tie('inline'), { depthIdentifier, maxLength: 4 }))
   const contentByModel = {
     block: blockContent,
-    code: fc.array(text.map((held): AdfNode => ({ text: held, type: 'text' })), { maxLength: 2 }),
+    code: occasionallyApart(fc.array(text.map((held): AdfNode => ({ text: held, type: 'text' })), { maxLength: 2 })),
     inline: inlineContent,
     none: fc.constant<AdfNode[]>([]),
   }
@@ -116,35 +138,40 @@ const positions = fc.letrec<Positions>((tie) => {
   const blockArbitraries = Object.entries(blockNodes).map(([type, model]) => {
     const argument = blockArgument(type)
     const vocabulary: AttributeVocabulary = argument === undefined ? model.attributes : { ...model.attributes, [argument]: 'string' }
-    const node = fc.record({ attrs: attributes(vocabulary), content: contentByModel[model.contentModel], marks: blockMarks }).map((held): AdfNode => ({ ...held, type }))
+    const node = occasionallyEmpty(fc.record({ attrs: attributes(vocabulary), content: contentByModel[model.contentModel], marks: blockMarks }).map((held): AdfNode => ({ ...held, type })))
     return { leaf: model.contentModel === 'code' || model.contentModel === 'none', node }
   })
-  const unknownNode = fc
+  const unknownNode = occasionallyEmpty(
-    .record({ attrs: fc.dictionary(jsonKey, jsonValue, { maxKeys: 2, noNullPrototype: true }), content: fc.array(tie('inline'), { depthIdentifier, maxLength: 2 }), marks, type: unknownType })
+    fc.record({ attrs: fc.dictionary(jsonKey, jsonValue, { maxKeys: 2, noNullPrototype: true }), content: fc.array(tie('inline'), { depthIdentifier, maxLength: 2 }), marks, type: unknownType }),
-    .map((held): AdfNode => held)
+  )
   const leafBlocks = blockArbitraries.filter((entry) => entry.leaf).map((entry) => entry.node)
   const containerBlocks = blockArbitraries.filter((entry) => !entry.leaf).map((entry) => entry.node)
   const misplacedWeight = 7
-  const paragraph = fc.oneof({ arbitrary: inlineContent, weight: 3 }, { arbitrary: fc.array(backtickRunNode, { maxLength: 4, minLength: 2 }), weight: 1 }).map((content): AdfNode => ({ content, type: 'paragraph' }))
+  const paragraph = occasionallyEmpty(
+    fc.oneof({ arbitrary: inlineContent, weight: 3 }, { arbitrary: occasionallyApart(fc.array(backtickRunNode, { maxLength: 4, minLength: 2 })), weight: 1 }).map((content): AdfNode => ({ content, type: 'paragraph' })),
+  )
   const cell = (type: string) => paragraph.map((held): AdfNode => ({ content: [held], type }))
   const listItems = fc.array(
-    blockContent.map((content): AdfNode => ({ content, type: 'listItem' })),
+    occasionallyEmpty(blockContent.map((content): AdfNode => ({ content, type: 'listItem' }))),
     { depthIdentifier, maxLength: 3, minLength: 1 },
   )
   const flatCommonMarkShapes = [
-    fc.record({ content: inlineContent, level: fc.integer({ max: 6, min: 1 }) }).map(({ content, level }): AdfNode => ({ attrs: { level }, content, type: 'heading' })),
+    occasionallyEmpty(fc.record({ content: inlineContent, level: fc.integer({ max: 6, min: 1 }) }).map(({ content, level }): AdfNode => ({ attrs: { level }, content, type: 'heading' }))),
     paragraph,
     fc.record({ body: fc.array(fc.array(cell('tableCell'), { maxLength: 3 }), { maxLength: 2 }), header: fc.array(cell('tableHeader'), { maxLength: 3, minLength: 1 }) }).map(pipeTable),
   ]
   const task = (type: string, content: Arbitrary<AdfNode[]>) =>
-    fc.record({ content, state: fc.constantFrom('DONE', 'TODO') }).map(({ content: held, state }): AdfNode => ({ attrs: { state }, content: held, type }))
+    occasionallyEmpty(fc.record({ content, state: fc.constantFrom('DONE', 'TODO') }).map(({ content: held, state }): AdfNode => ({ attrs: { state }, content: held, type })))
   const taskItem = fc.oneof({ arbitrary: task('taskItem', inlineContent), weight: 3 }, { arbitrary: task('blockTaskItem', blockContent), weight: 1 })
   const nestingCommonMarkShapes = [
-    blockContent.map((content): AdfNode => ({ content, type: 'blockquote' })),
+    occasionallyEmpty(blockContent.map((content): AdfNode => ({ content, type: 'blockquote' }))),
     fc.array(fc.oneof({ arbitrary: taskItem, weight: 3 }, { arbitrary: tie('block'), weight: 1 }), { depthIdentifier, maxLength: 3, minLength: 1 }).map((content): AdfNode => ({ content, type: 'taskList' })),
     listItems.map((content): AdfNode => ({ content, type: 'bulletList' })),
     fc
-      .record({ content: listItems, order: fc.oneof({ arbitrary: fc.integer({ max: 3, min: 0 }), weight: 4 }, { arbitrary: fc.integer({ max: 999999999, min: 0 }), weight: 1 }) })
+      .record({
+        content: listItems,
+        order: fc.oneof({ arbitrary: fc.integer({ max: 3, min: 0 }), weight: 8 }, { arbitrary: fc.integer({ max: 999999999, min: 0 }), weight: 2 }, { arbitrary: fc.constant(-0), weight: 1 }),
+      })
       .map(({ content, order }): AdfNode => ({ attrs: { order }, content, type: 'orderedList' })),
   ]
   const flatBlocks = [...weighted(leafBlocks, 2), ...weighted(flatCommonMarkShapes, flatCommonMarkShapeWeight)]
@@ -167,7 +194,11 @@ const positions = fc.letrec<Positions>((tie) => {
   }
 })
 
-export const adfDocument = fc.array(positions.block, { depthIdentifier, maxLength: 4, minLength: 1 }).map((content): AdfDocument => toEditorNormal({ content, type: 'doc', version: 1 }))
+export const adfDocument = fc.oneof(
+  { arbitrary: fc.array(positions.block, { depthIdentifier, maxLength: 4, minLength: 1 }).map((content): AdfDocument => ({ content, type: 'doc', version: 1 })), weight: 30 },
+  { arbitrary: fc.constant<AdfDocument>({ content: [], type: 'doc', version: 1 }), weight: 1 },
+  { arbitrary: fc.constant<AdfDocument>({ type: 'doc', version: 1 }), weight: 1 },
+)
 
 export function propertyRuns(gateRuns: number): { gate: boolean; numRuns: number; seed?: number } {
   const deepRuns = env[deepRunsVariable]

src/markdown/block-directive.ts

@@ -2,7 +2,7 @@ import type { AdfMark } from '../adf/document.ts'
 import type { BlockType } from '../adf/block-nodes.ts'
 import type { JsonValue } from '../json-value.ts'
 import { blockNodeModel } from '../adf/block-nodes.ts'
-import { isAdfMark, nodeAttrs } from '../adf/document.ts'
+import { isAdfMark } from '../adf/document.ts'
 import { serializeCanonicalJson } from '../canonical-json.ts'
 import { spellDirectiveOpener } from './directive-syntax.ts'
 
@@ -14,6 +14,11 @@ const argumentByType = new Map(
   } satisfies Partial<Record<BlockType, string>>),
 )
 
+export const documentName = 'doc'
+
+// spec/flavour.md, Directives: a document holding no content key, which the empty string cannot spell.
+export const documentSpelling = spellDirectiveOpener(documentName, undefined, '{content=none}')
+
 export const listBreakName = 'listBreak'
 
 export const listBreakSpelling = spellDirectiveOpener(listBreakName, undefined, '')
@@ -25,17 +30,14 @@ export function blockArgument(type: string): string | undefined {
 }
 
 export function blockDirectiveForm(name: string): 'container' | 'leaf' | undefined {
-  if (name === listBreakName) return 'leaf'
+  if (name === listBreakName || name === documentName) return 'leaf'
   const model = blockNodeModel(name)
   if (model === undefined) return undefined
   return model.contentModel === 'none' ? 'leaf' : 'container'
 }
 
 export function markValues(marks: readonly AdfMark[]): JsonValue {
-  return marks.map((mark) => {
+  return marks.map((mark) => (mark.attrs === undefined ? { type: mark.type } : { attrs: mark.attrs, type: mark.type }))
-    const attrs = nodeAttrs(mark)
-    return Object.keys(attrs).length === 0 ? { type: mark.type } : { attrs, type: mark.type }
-  })
 }
 
 export function readMarkValues(value: JsonValue): AdfMark[] | undefined {

src/markdown/code-language.ts

@@ -1,14 +1,12 @@
 import type { JsonValue } from '../json-value.ts'
-import { carryName } from './opaque-carry.ts'
+import { carryFencePrefix } from './opaque-carry.ts'
-import { holdsControlCharacter } from './commonmark/grammar.ts'
+import { infoStringCarries } from './commonmark/grammar.ts'
-import { holdsEntityReference } from './commonmark/entity-references.ts'
 
 export type LanguageSlot = { info: string; kind: 'fence' } | { kind: 'attribute' } | { kind: 'none' }
 
 // spec/flavour.md, The CommonMark blocks: the one slot a codeBlock's language rides.
 export function languageSlot(language: JsonValue | undefined): LanguageSlot {
   if (language === undefined) return { kind: 'none' }
-  if (typeof language !== 'string' || language === '' || language === carryName) return { kind: 'attribute' }
+  if (typeof language !== 'string' || language.startsWith(carryFencePrefix) || !infoStringCarries(language)) return { kind: 'attribute' }
-  if (/[`\\]/.test(language) || holdsControlCharacter(language) || language !== language.trim() || holdsEntityReference(language)) return { kind: 'attribute' }
   return { info: language, kind: 'fence' }
 }

src/markdown/commonmark/grammar.ts

@@ -1,4 +1,4 @@
-import { readEntityReference, replacementCharacter } from './entity-references.ts'
+import { holdsEntityReference, readEntityReference, replacementCharacter } from './entity-references.ts'
 
 export type LinePosition = 'first' | 'later'
 
@@ -133,6 +133,11 @@ export function holdsControlCharacter(text: string): boolean {
   return controlCharacter.test(text)
 }
 
+// What a backtick fence's info string reads back verbatim: escapes and entity references decode, and the edges trim.
+export function infoStringCarries(text: string): boolean {
+  return text !== '' && !/[`\\]/.test(text) && !holdsControlCharacter(text) && text === text.trim() && !holdsEntityReference(text)
+}
+
 export function holdsNullCharacter(text: string): boolean {
   return nullCharacter.test(text)
 }

src/markdown/directive-syntax.ts

@@ -139,7 +139,7 @@ export function spellStringAttribute(text: string): string {
 export function spellAttributeValue(value: VocabularyValue): string {
   if (value.kind === 'boolean') return `${value.value}`
   if (value.kind === 'json') return spellJsonAttribute(value.value)
-  if (value.kind === 'number') return spellStringAttribute(JSON.stringify(value.value))
+  if (value.kind === 'number') return spellStringAttribute(serializeCanonicalJson(value.value, 'compact'))
   return spellStringAttribute(value.value)
 }
 

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

@@ -6,14 +6,13 @@ import type { JsonValue } from '../../json-value.ts'
 import type { Result } from '../../result.ts'
 import { adfToMarkdown, markdownToAdf } from '../../index.ts'
 import { largestNesting } from '../../nesting.ts'
-import { toEditorNormal } from '../../adf/editor-normal.ts'
 
 function document(...content: AdfNode[]): AdfDocument {
   return { content, type: 'doc', version: 1 }
 }
 
 function paragraph(...content: AdfNode[]): AdfNode {
-  return { content, type: 'paragraph' }
+  return content.length === 0 ? { type: 'paragraph' } : { content, type: 'paragraph' }
 }
 
 function code(result: Result<string>): string {
@@ -168,21 +167,24 @@ test('parts two adjacent lists of the same kind, the marker spelling being what
   const nested: AdfNode = { content: [{ content: [list, list], type: 'listItem' }], type: 'bulletList' }
   assert.equal(markdown(adfToMarkdown(document(nested))), '- - x\n\n  !adf:listBreak\n\n  - x\n')
   const carried: AdfNode = { ...list, attrs: { unknown: 'x' } }
-  assert.ok(markdown(adfToMarkdown(document(carried, carried))).includes('```\n\n```carry\n'))
+  assert.ok(markdown(adfToMarkdown(document(carried, carried))).includes('```\n\n```adf:bulletList\n'))
   assert.ok(markdown(adfToMarkdown(document(carried, list))).endsWith('```\n\n- x\n'))
-  assert.ok(markdown(adfToMarkdown(document(list, carried))).startsWith('- x\n\n```carry\n'))
+  assert.ok(markdown(adfToMarkdown(document(list, carried))).startsWith('- x\n\n```adf:bulletList\n'))
 })
 
-test('carries a node type no section spells', () => {
+test('carries a node type no section spells, the fence naming the type wherever an info string carries it', () => {
-  assert.equal(markdown(adfToMarkdown(document({ type: 'blockCard' }))), '```carry\n{\n  "type": "blockCard"\n}\n```\n')
+  assert.equal(markdown(adfToMarkdown(document({ type: 'blockCard' }))), '```adf:blockCard\n{}\n```\n')
-  assert.equal(markdown(adfToMarkdown(document({ type: 'toString' }))), '```carry\n{\n  "type": "toString"\n}\n```\n')
+  assert.equal(markdown(adfToMarkdown(document({ type: 'toString' }))), '```adf:toString\n{}\n```\n')
   assert.equal(markdown(adfToMarkdown(document(paragraph({ type: 'blockCard' })))), '!adf:carry{json="{\\"type\\":\\"blockCard\\"}"}\n')
-  assert.equal(markdown(adfToMarkdown(document({ text: 'x', type: 'text' }))), '```carry\n{\n  "text": "x",\n  "type": "text"\n}\n```\n')
+  assert.equal(markdown(adfToMarkdown(document({ text: 'x', type: 'text' }))), '```adf:text\n{\n  "text": "x"\n}\n```\n')
-  assert.equal(markdown(adfToMarkdown(document({ type: 'hardBreak' }))), '```carry\n{\n  "type": "hardBreak"\n}\n```\n')
+  assert.equal(markdown(adfToMarkdown(document({ type: 'hardBreak' }))), '```adf:hardBreak\n{}\n```\n')
+  assert.equal(markdown(adfToMarkdown(document({ type: 'a&amp;b' }))), '```adf:\n{\n  "type": "a&amp;b"\n}\n```\n')
+  assert.equal(markdown(adfToMarkdown(document({ type: 'a\\b' }))), '```adf:\n{\n  "type": "a\\\\b"\n}\n```\n')
 })
 
-test('spells the code block whose language is the reserved info string', () => {
+test('spells the code block whose language opens with the reserved info string prefix', () => {
-  assert.equal(markdown(adfToMarkdown(document({ attrs: { language: 'carry' }, type: 'codeBlock' }))), '!adf:codeBlock {language=carry}\n```\n```\n!adf:/codeBlock\n')
+  assert.equal(markdown(adfToMarkdown(document({ attrs: { language: 'adf:x' }, type: 'codeBlock' }))), '!adf:codeBlock {language="adf:x"}\n```\n```\n!adf:/codeBlock\n')
+  assert.equal(markdown(adfToMarkdown(document({ attrs: { language: 'carry' }, type: 'codeBlock' }))), '```carry\n```\n')
   assert.equal(markdown(adfToMarkdown(document({ attrs: { language: 'adf' }, type: 'codeBlock' }))), '```adf\n```\n')
 })
 
@@ -208,21 +210,17 @@ test('refuses a carried node nested deeper than the levels its position leaves',
   assert.equal(code(adfToMarkdown(document(quoted))), 'unsupported-nesting-depth')
 })
 
-test('refuses a node whose content model the canonical form cannot emit', () => {
+test('carries a code block holding a node no fence holds', () => {
-  assert.equal(
+  assert.equal(markdown(adfToMarkdown(document({ content: [paragraph()], type: 'codeBlock' }))), '```adf:codeBlock\n{\n  "content": [\n    {\n      "type": "paragraph"\n    }\n  ]\n}\n```\n')
-    markdown(adfToMarkdown(document({ content: [paragraph()], type: 'codeBlock' }))),
+  for (const child of [{ attrs: {}, text: 'x', type: 'text' }, { content: [], text: 'x', type: 'text' }, { marks: [], text: 'x', type: 'text' }, { content: [{ text: 'lost', type: 'text' }], text: 'x', type: 'text' }]) {
-    'unsupported-node-shape: a codeBlock holds plain text nodes only: this paragraph node is not one',
+    assert.ok(markdown(adfToMarkdown(document({ content: [child], type: 'codeBlock' }))).startsWith('```adf:codeBlock\n'), JSON.stringify(child))
-  )
+  }
-  assert.equal(
-    markdown(adfToMarkdown(document({ content: [{ content: [{ text: 'lost', type: 'text' }], text: 'x', type: 'text' }], type: 'codeBlock' }))),
-    'unsupported-node-shape: a codeBlock holds plain text nodes only: this text node is not one',
-  )
 })
 
 test('spells a list its own content shape cannot hold as a directive', () => {
   assert.equal(markdown(adfToMarkdown(document({ content: [paragraph()], type: 'bulletList' }))), '!adf:bulletList\n!adf:paragraph\n!adf:/paragraph\n!adf:/bulletList\n')
   assert.equal(markdown(adfToMarkdown(document({ type: 'bulletList' }))), '!adf:bulletList\n!adf:/bulletList\n')
-  assert.equal(markdown(adfToMarkdown(document({ attrs: { order: 2 }, content: [], type: 'orderedList' }))), '!adf:orderedList {order=2}\n!adf:/orderedList\n')
+  assert.equal(markdown(adfToMarkdown(document({ attrs: { order: 2 }, content: [], type: 'orderedList' }))), '!adf:orderedList {content=empty order=2}\n!adf:/orderedList\n')
 })
 
 test('spells an ordered list no marker fits as a directive', () => {
@@ -334,7 +332,7 @@ test('refuses a node carrying one mark type twice', () => {
 })
 
 test('parts a nested list the tight spelling would swallow from the block above it', () => {
-  const item = (...content: AdfNode[]): AdfNode => ({ content, type: 'listItem' })
+  const item = (...content: AdfNode[]): AdfNode => (content.length === 0 ? { type: 'listItem' } : { content, type: 'listItem' })
   const text = (value: string): AdfNode => ({ content: [{ text: value, type: 'text' }], type: 'paragraph' })
   const outer = (...content: AdfNode[]): AdfDocument => document({ content: [item(...content)], type: 'bulletList' })
   const ordered: AdfNode = { attrs: { order: 2 }, content: [item(text('b'))], type: 'orderedList' }
@@ -345,7 +343,7 @@ test('parts a nested list the tight spelling would swallow from the block above
   const list: AdfNode = { content: [item(text('b'))], type: 'bulletList' }
   const panel: AdfNode = { attrs: { panelType: 'info' }, content: [text('p')], type: 'panel' }
   assert.equal(markdown(adfToMarkdown(outer(panel, list))), '- !adf:panel info\n  p\n  !adf:/panel\n\n  - b\n')
-  assert.ok(markdown(adfToMarkdown(outer(text('a'), { ...list, attrs: { unknown: 'x' } }))).startsWith('- a\n\n  ```carry\n'))
+  assert.ok(markdown(adfToMarkdown(outer(text('a'), { ...list, attrs: { unknown: 'x' } }))).startsWith('- a\n\n  ```adf:bulletList\n'))
 })
 
 test('refuses marks and attributes nested deeper than the emitter carries', () => {
@@ -372,7 +370,7 @@ test('refuses marks and attributes nested deeper than the emitter carries', () =
     assert.ok(spelled.ok, spelled.ok ? '' : spelled.error.message)
     const read = markdownToAdf(spelled.value)
     assert.ok(read.ok, read.ok ? '' : read.error.message)
-    assert.deepEqual(toEditorNormal(read.value), document(node))
+    assert.deepEqual(read.value, document(node))
   }
 
   assert.equal(markdown(adfToMarkdown(document(paragraph({ marks: [{ attrs, type: 'em' }], text: 'x', type: 'text' })))), deeper('depth', 'em'))
@@ -442,7 +440,7 @@ test('escapes a hyphen underline a hard break would expose', () => {
 })
 
 test('spells a list item whose marker completes a thematic break as a directive', () => {
-  const item = (...content: AdfNode[]): AdfNode => ({ content, type: 'listItem' })
+  const item = (...content: AdfNode[]): AdfNode => (content.length === 0 ? { type: 'listItem' } : { content, type: 'listItem' })
   assert.equal(markdown(adfToMarkdown(document({ content: [item({ type: 'rule' })], type: 'bulletList' }))), '!adf:bulletList\n!adf:listItem\n---\n!adf:/listItem\n!adf:/bulletList\n')
   const nested: AdfNode = { content: [item({ content: [item()], type: 'bulletList' })], type: 'bulletList' }
   assert.equal(markdown(adfToMarkdown(document(nested))), '- -\n')
@@ -469,10 +467,7 @@ test('refuses the characters CommonMark rewrites', () => {
   )
   assert.equal(code(adfToMarkdown(document(paragraph({ text: 'a\u0000b', type: 'text' })))), 'unspellable-character')
   assert.equal(code(adfToMarkdown(document({ content: [{ text: 'a\u0000b', type: 'text' }], type: 'codeBlock' }))), 'unspellable-character')
-  assert.equal(
+  assert.equal(markdown(adfToMarkdown(document({ content: [{ text: '', type: 'text' }], type: 'codeBlock' }))), 'unsupported-node-shape: a text node holds text: this one has none')
-    markdown(adfToMarkdown(document({ content: [{ text: '', type: 'text' }], type: 'codeBlock' }))),
-    'unsupported-node-shape: a codeBlock holds plain text nodes only: this text node is not one',
-  )
 })
 
 test('refuses a text node the spelling would empty out', () => {
@@ -501,11 +496,11 @@ test('pads a code span whose edges CommonMark would strip', () => {
   assert.equal(markdown(adfToMarkdown(document(paragraph({ marks: [{ type: 'code' }], text: ' \t ', type: 'text' })))), '`  \t  `\n')
 })
 
-test('spells one code span over a run of code-marked nodes', () => {
+test('spells a code span per code-marked node, parted by the text break', () => {
   const code_ = { type: 'code' }
   assert.equal(
     markdown(adfToMarkdown(document(paragraph({ marks: [code_], text: 'a', type: 'text' }, { marks: [code_], text: 'b', type: 'text' })))),
-    '`ab`\n',
+    '`a`!adf:textBreak{}`b`\n',
   )
 })
 
@@ -545,7 +540,7 @@ test('emits an empty list item without trailing whitespace', () => {
 test('spells a block directive as its node type, arg and attributes', () => {
   const panel = (attrs: AdfAttributes): AdfDocument => document({ attrs, content: [paragraph({ text: 'x', type: 'text' })], type: 'panel' })
   assert.equal(markdown(adfToMarkdown(panel({ panelType: 'warning' }))), '!adf:panel warning\nx\n!adf:/panel\n')
-  assert.equal(markdown(adfToMarkdown(panel({}))), '!adf:panel\nx\n!adf:/panel\n')
+  assert.equal(markdown(adfToMarkdown(panel({}))), '!adf:panel {attrs=empty}\nx\n!adf:/panel\n')
   assert.equal(markdown(adfToMarkdown(document({ content: [{ text: 'x', type: 'text' }], type: 'caption' }))), '!adf:caption\nx\n!adf:/caption\n')
   assert.equal(markdown(adfToMarkdown(document({ type: 'caption' }))), '!adf:caption\n!adf:/caption\n')
   assert.equal(markdown(adfToMarkdown(document({ attrs: { localId: 'a' }, type: 'syncBlock' }))), '!adf:syncBlock {localId=a}\n')
@@ -553,20 +548,20 @@ test('spells a block directive as its node type, arg and attributes', () => {
 
 test('carries a directive attribute no section spells', () => {
   const carried = (node: AdfNode): string => markdown(adfToMarkdown(document(node)))
-  assert.equal(carried({ attrs: { rounded: true }, type: 'panel' }), '```carry\n{\n  "attrs": {\n    "rounded": true\n  },\n  "type": "panel"\n}\n```\n')
+  assert.equal(carried({ attrs: { rounded: true }, type: 'panel' }), '```adf:panel\n{\n  "attrs": {\n    "rounded": true\n  }\n}\n```\n')
-  assert.equal(carried({ attrs: { toString: 'x' }, type: 'panel' }), '```carry\n{\n  "attrs": {\n    "toString": "x"\n  },\n  "type": "panel"\n}\n```\n')
+  assert.equal(carried({ attrs: { toString: 'x' }, type: 'panel' }), '```adf:panel\n{\n  "attrs": {\n    "toString": "x"\n  }\n}\n```\n')
-  assert.equal(carried({ attrs: { localId: 4 }, type: 'panel' }), '```carry\n{\n  "attrs": {\n    "localId": 4\n  },\n  "type": "panel"\n}\n```\n')
+  assert.equal(carried({ attrs: { localId: 4 }, type: 'panel' }), '```adf:panel\n{\n  "attrs": {\n    "localId": 4\n  }\n}\n```\n')
   assert.equal(
     carried({ attrs: { width: '50' }, type: 'layoutColumn' }),
-    '```carry\n{\n  "attrs": {\n    "width": "50"\n  },\n  "type": "layoutColumn"\n}\n```\n',
+    '```adf:layoutColumn\n{\n  "attrs": {\n    "width": "50"\n  }\n}\n```\n',
   )
   assert.equal(
     carried({ attrs: { isNumberColumnEnabled: 'true' }, type: 'table' }),
-    '```carry\n{\n  "attrs": {\n    "isNumberColumnEnabled": "true"\n  },\n  "type": "table"\n}\n```\n',
+    '```adf:table\n{\n  "attrs": {\n    "isNumberColumnEnabled": "true"\n  }\n}\n```\n',
   )
   assert.equal(
     carried({ content: [{ attrs: { alt: 4 }, type: 'media' }], type: 'mediaGroup' }),
-    '!adf:mediaGroup\n```carry\n{\n  "attrs": {\n    "alt": 4\n  },\n  "type": "media"\n}\n```\n!adf:/mediaGroup\n',
+    '!adf:mediaGroup\n```adf:media\n{\n  "attrs": {\n    "alt": 4\n  }\n}\n```\n!adf:/mediaGroup\n',
   )
 })
 
@@ -574,15 +569,16 @@ test('carries an arg slot value no bare token spells', () => {
   const carried = (node: AdfNode): string => markdown(adfToMarkdown(document(node)))
   assert.equal(
     carried({ attrs: { panelType: 'extra info' }, type: 'panel' }),
-    '```carry\n{\n  "attrs": {\n    "panelType": "extra info"\n  },\n  "type": "panel"\n}\n```\n',
+    '```adf:panel\n{\n  "attrs": {\n    "panelType": "extra info"\n  }\n}\n```\n',
   )
-  assert.equal(carried({ attrs: { state: 2 }, type: 'taskItem' }), '```carry\n{\n  "attrs": {\n    "state": 2\n  },\n  "type": "taskItem"\n}\n```\n')
+  assert.equal(carried({ attrs: { state: 2 }, type: 'taskItem' }), '```adf:taskItem\n{\n  "attrs": {\n    "state": 2\n  }\n}\n```\n')
 })
 
 test('carries a block node mark in the reserved attribute', () => {
   const section = (...marks: AdfMark[]): AdfDocument => document({ marks, type: 'layoutSection' })
   assert.equal(markdown(adfToMarkdown(section({ type: 'breakout' }))), '!adf:layoutSection {marks="[{\\"type\\":\\"breakout\\"}]"}\n!adf:/layoutSection\n')
-  assert.equal(markdown(adfToMarkdown(section({ attrs: {}, type: 'breakout' }))), '!adf:layoutSection {marks="[{\\"type\\":\\"breakout\\"}]"}\n!adf:/layoutSection\n')
+  assert.equal(markdown(adfToMarkdown(section({ attrs: {}, type: 'breakout' }))), '!adf:layoutSection {marks="[{\\"attrs\\":{},\\"type\\":\\"breakout\\"}]"}\n!adf:/layoutSection\n')
+  assert.equal(markdown(adfToMarkdown(section())), '!adf:layoutSection {marks=empty}\n!adf:/layoutSection\n')
 })
 
 test('refuses the content a directive body has no room for', () => {
@@ -604,7 +600,7 @@ test('separates blocks in a container body by a blank line only where a directiv
 test('spells the image form for exactly the centered external media shape', () => {
   const url = 'https://example.com/moon.png'
   const single = (attrs: AdfAttributes, ...content: AdfNode[]): AdfDocument =>
-    document({ attrs: { layout: 'center' }, content: [{ attrs, content, type: 'media' }], type: 'mediaSingle' })
+    document({ attrs: { layout: 'center' }, content: [content.length === 0 ? { attrs, type: 'media' } : { attrs, content, type: 'media' }], type: 'mediaSingle' })
   assert.equal(markdown(adfToMarkdown(single({ alt: 'The moon', type: 'external', url }))), `![The moon](${url})\n`)
   assert.equal(markdown(adfToMarkdown(single({ type: 'external', url }))), `![](${url})\n`)
   assert.equal(markdown(adfToMarkdown(single({ alt: 'a [b] c', type: 'external', url }))), `![a \\[b\\] c](${url})\n`)
@@ -701,7 +697,8 @@ test('spells the directive marks around the longest run they cover', () => {
   const emitted = (...content: AdfNode[]): string => markdown(adfToMarkdown(document(paragraph(...content))))
   const underline: AdfMark = { type: 'underline' }
   assert.equal(emitted(marked('x', underline)), '!adf:underline[x]\n')
-  assert.equal(emitted(marked('a', underline), marked('b', underline)), '!adf:underline[ab]\n')
+  assert.equal(emitted(marked('a', underline), marked('b', underline)), '!adf:underline[a!adf:textBreak{}b]\n')
+  assert.equal(emitted(marked('a', { attrs: {}, type: 'underline' }), marked('b', underline)), '!adf:underline[a]{attrs=empty}!adf:underline[b]\n')
   assert.equal(emitted(marked('x', { attrs: { type: 'sub' }, type: 'subsup' })), '!adf:subsup[x]{type=sub}\n')
   assert.equal(emitted(marked('x', { attrs: { color: '#ae2e24' }, type: 'textColor' })), '!adf:textColor[x]{color="#ae2e24"}\n')
   assert.equal(emitted(marked('x', { attrs: { color: '#091e42', size: 2 }, type: 'border' })), '!adf:border[x]{color="#091e42" size=2}\n')
@@ -746,5 +743,5 @@ test('carries whitespace CommonMark strips in the reserved text directive', () =
 
 test("joins a mark run's segments as a walk rather than as one call's arguments", () => {
   const run = Array.from({ length: 200000 }, (): AdfNode => ({ marks: [{ type: 'strong' }], text: 'a', type: 'text' }))
-  assert.equal(markdown(adfToMarkdown(document({ content: run, type: 'paragraph' }))), `**${'a'.repeat(200000)}**\n`)
+  assert.equal(markdown(adfToMarkdown(document({ content: run, type: 'paragraph' }))), `**${Array.from({ length: 200000 }, () => 'a').join('!adf:textBreak{}')}**\n`)
 })

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

@@ -1,16 +1,16 @@
 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, nodeMarks } from '../../adf/document.ts'
+import { adfDocumentFault, carriesOnly, nodeAttrs, nodeContent } from '../../adf/document.ts'
 import { alertMarker, foldedAlertMarker, leadingMarker, readAlertMarker, readTaskMarker, taskMarker } from '../plain-conventions.ts'
-import { blockDirectiveForm, listBreakSpelling } from '../block-directive.ts'
+import { blockDirectiveForm, documentSpelling, listBreakSpelling } from '../block-directive.ts'
 import { blockNodeModel, blockNodes } from '../../adf/block-nodes.ts'
 import { carriedBlock } from '../opaque-carry.ts'
 import { emitInlineLine } from './inline-line.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { fencedCodeBlock } from '../commonmark/backtick-runs.ts'
 import { holdsNullCharacter, isBlankLine, isThematicBreak, markerInterruptsParagraph } from '../commonmark/grammar.ts'
-import { languageSlot } from '../code-language.ts'
+import { languageSlot, type LanguageSlot } from '../code-language.ts'
 import { largestNesting } from '../../nesting.ts'
 import { spellBlockDirectiveOpener } from './block-directive-spelling.ts'
 import { spellDirectiveCloser, spellDirectiveOpener } from '../directive-syntax.ts'
@@ -40,7 +40,8 @@ export function writeMarkdown(document: AdfDocument, flavour: Flavour): Result<s
   const fault = adfDocumentFault(document)
   if (fault !== undefined) return faulted(fault, [])
   if (document.version !== 1) return failure('unsupported-document-version', `no markdown spelling carries ADF version ${document.version}`, [])
-  const walk = walkBlocks(nodeContent(document), [], 0, { flavour, memo: undefined })
+  if (document.content === undefined) return success(`${documentSpelling}\n`)
+  const walk = walkBlocks(document.content, [], 0, { flavour, memo: undefined })
   if (!walk.ok) return walk
   const text = joinBlocks(walk.value.blocks, 'document')
   return success(text === '' ? '' : `${text}\n`)
@@ -254,40 +255,39 @@ function tryCodeBlock(node: AdfNode, path: ConvertErrorPath): Result<EmittedBloc
   if (!carriesOnly(node, ['language'])) return undefined
   const slot = languageSlot(nodeAttrs(node)['language'])
   if (slot.kind === 'attribute') return undefined
-  const text = codeBlockText(node, path)
+  const texts = fencedTexts(node, path)
-  if (!text.ok) return text
+  if (!texts.ok) return texts
-  return success(commonMarkText(fencedCodeBlock(slot.kind === 'fence' ? slot.info : '', text.value)))
+  const [only, ...others] = texts.value ?? []
+  if (only === undefined || others.length > 0) return undefined
+  return success(commonMarkText(fencedCodeBlock(slot.kind === 'fence' ? slot.info : '', only)))
 }
 
+// spec/flavour.md, The CommonMark blocks: one fence per text node, the language on each; with no fence to carry it, the attribute does.
 function emitCodeDirective(node: AdfNode, model: BlockNodeModel, path: ConvertErrorPath, depth: number): Result<EmittedBlock> {
-  const slot = languageSlot(nodeAttrs(node)['language'])
+  const texts = fencedTexts(node, path)
+  if (!texts.ok) return texts
+  if (texts.value === undefined) return commonMarkLine(carriedBlock(node, path, depth))
+  const slot: LanguageSlot = texts.value.length === 0 ? { kind: 'attribute' } : languageSlot(nodeAttrs(node)['language'])
   const opener = spellBlockDirectiveOpener(node, model, path, slot.kind === 'attribute' ? [] : ['language'])
   if (opener === undefined) return commonMarkLine(carriedBlock(node, path, depth))
   if (!opener.ok) return opener
-  const text = codeBlockText(node, path)
+  const info = slot.kind === 'fence' ? slot.info : ''
-  if (!text.ok) return text
+  return success(directivePair(node, opener.value, texts.value.map((text) => fencedCodeBlock(info, text)).join('\n')))
-  return success(directivePair(node, opener.value, fencedCodeBlock(slot.kind === 'fence' ? slot.info : '', text.value)))
 }
 
-function codeBlockText(node: AdfNode, path: ConvertErrorPath): Result<string> {
+// The text each fence holds, or `undefined` where a child is no plain text node, which the carry holds instead.
-  let text = ''
+function fencedTexts(node: AdfNode, path: ConvertErrorPath): Result<string[] | undefined> {
-  for (const [index, child] of nodeContent(node).entries()) {
+  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)
+  const texts: string[] = []
+  for (const [index, child] of node.content.entries()) {
     const childPath = [...path, 'content', index]
-    if (
+    if (typeof child.text !== 'string' || child.text === '') return failure('unsupported-node-shape', 'a text node holds text: this one has none', childPath)
-      child.type !== 'text' ||
-      typeof child.text !== 'string' ||
-      child.text === '' ||
-      nodeContent(child).length > 0 ||
-      nodeMarks(child).length > 0 ||
-      Object.keys(nodeAttrs(child)).length > 0
-    ) {
-      return failure('unsupported-node-shape', `a codeBlock holds plain text nodes only: this ${child.type} node is not one`, childPath)
-    }
     if (/\r/.test(child.text)) return failure('unspellable-character', 'a codeBlock holds no carriage return CommonMark keeps: this text holds one', childPath)
     if (holdsNullCharacter(child.text)) return failure('unspellable-character', 'a codeBlock holds a null character CommonMark replaces', childPath)
-    text += child.text
+    texts.push(child.text)
   }
-  return success(text)
+  return success(texts)
 }
 
 function tryHeading(node: AdfNode, path: ConvertErrorPath, flavour: Flavour): Result<EmittedBlock> | undefined {
@@ -340,7 +340,7 @@ function directiveItems(items: readonly WalkedItem[]): PlacedBlock[] {
 function listStart(node: AdfNode, items: number): number | undefined {
   if (node.type !== 'orderedList') return 0
   const start = nodeAttrs(node)['order']
-  if (typeof start !== 'number' || !Number.isInteger(start) || start < 0 || start > largestListMarker) return undefined
+  if (typeof start !== 'number' || !Number.isInteger(start) || start < 0 || Object.is(start, -0) || start > largestListMarker) return undefined
   return start + items - 1 > largestListMarker ? undefined : start
 }
 

src/markdown/emit/block-directive-spelling.ts

@@ -5,6 +5,7 @@ import { blockArgument, markValues, marksAttribute } from '../block-directive.ts
 import { failure, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { isBareToken, spellAttributes, spellDirectiveOpener, spellJsonAttribute, spellVocabulary } from '../directive-syntax.ts'
 import { overNested } from '../../json-value.ts'
+import { spellEmptyKeys } from '../empty-keys.ts'
 import { vocabularyPairs } from '../../adf/attribute-vocabulary.ts'
 
 export function spellBlockDirectiveOpener(node: AdfNode, model: BlockNodeModel, path: ConvertErrorPath, spelledByBody: readonly string[] = []): Result<string> | undefined {
@@ -14,7 +15,7 @@ export function spellBlockDirectiveOpener(node: AdfNode, model: BlockNodeModel,
   const spelled = argumentAttribute === undefined ? spelledByBody : [argumentAttribute, ...spelledByBody]
   const pairs = vocabularyPairs(nodeAttrs(node), model.attributes, spelled)
   if (pairs === undefined) return undefined
-  const spelledPairs = spellVocabulary(pairs)
+  const spelledPairs = [...spellVocabulary(pairs), ...spellEmptyKeys(node)]
   const marks = nodeMarks(node)
   if (marks.length > 0) {
     const values = markValues(marks)

src/markdown/emit/inline-directive-spelling.ts

@@ -2,9 +2,10 @@ import type { AdfNode } from '../../adf/document.ts'
 import type { InlineNodeModel } from '../../adf/inline-nodes.ts'
 import { nodeAttrs } from '../../adf/document.ts'
 import { spellAttributes, spellVocabulary } from '../directive-syntax.ts'
+import { spellEmptyKeys } from '../empty-keys.ts'
 import { vocabularyPairs } from '../../adf/attribute-vocabulary.ts'
 
 export function spellInlineNodeAttributes(node: AdfNode, model: InlineNodeModel): string | undefined {
   const pairs = vocabularyPairs(nodeAttrs(node), model.attributes, model.textAttribute === undefined ? [] : [model.textAttribute])
-  return pairs === undefined ? undefined : spellAttributes(spellVocabulary(pairs))
+  return pairs === undefined ? undefined : spellAttributes([...spellVocabulary(pairs), ...spellEmptyKeys(node)])
 }

src/markdown/emit/inline-line.ts

@@ -6,14 +6,14 @@ 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 { escapeUnbalanced, spellDestination } from '../commonmark/link-syntax.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { highlightDelimiter } from '../plain-conventions.ts'
 import { inlineNodeModel } from '../../adf/inline-nodes.ts'
 import { largestNesting } from '../../nesting.ts'
 import { longestBacktickRun } from '../commonmark/backtick-runs.ts'
-import { nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
+import { readsAsOne, textBreakSpelling } from '../text-break.ts'
-import { sameMark } from '../../adf/editor-normal.ts'
 import { slotLineEndingFault, spellInlineDirectiveOpener, spellInlineLeafDirective } from '../directive-syntax.ts'
 import { spellInlineNodeAttributes } from './inline-directive-spelling.ts'
 import { spellTextDirective } from '../text-directive.ts'
@@ -186,6 +186,7 @@ function emitRun(nodes: readonly AdfNode[], depth: number, firstIndex: number, c
   const runs = inlineRuns(nodes, depth, firstIndex, context.carried)
   const segments: InlineSegment[] = []
   for (const [offset, run] of runs.entries()) {
+    if (partsText(runs[offset - 1], run, context.carried)) segments.push(syntax(textBreakSpelling))
     const runContext = { ...context, atBlockEnd: context.atBlockEnd && offset === runs.length - 1 }
     const emitted = run.kind === 'plain' ? emitLeaf(run.node, runContext, run.index) : emitMarkedRun(run.nodes, run.mark, depth, run.index, runContext)
     if (!emitted.ok) return emitted
@@ -206,12 +207,18 @@ function inlineRuns(nodes: readonly AdfNode[], depth: number, firstIndex: number
       continue
     }
     const previous = runs[runs.length - 1]
-    if (previous?.kind === 'marked' && sameMark(previous.mark, mark)) previous.nodes.push(node)
+    if (previous?.kind === 'marked' && identicalMark(previous.mark, mark)) previous.nodes.push(node)
     else runs.push({ index, kind: 'marked', mark, nodes: [node] })
   }
   return runs
 }
 
+function partsText(previous: InlineRun | undefined, run: InlineRun, carried: ReadonlySet<number>): boolean {
+  if (previous?.kind !== 'plain' || run.kind !== 'plain') return false
+  if (carries(previous.node, carried, previous.index) || carries(run.node, carried, run.index)) return false
+  return readsAsOne(previous.node, run.node)
+}
+
 function nodePath(context: InlineContext, index: number): ConvertErrorPath {
   return [...context.path, 'content', index]
 }
@@ -261,7 +268,7 @@ function emitInlineDirective(node: AdfNode, model: InlineNodeModel, index: numbe
 }
 
 function emitText(node: AdfNode, context: InlineContext, index: number, path: ConvertErrorPath): Result<Emission> {
-  if (Object.keys(nodeAttrs(node)).length > 0) return success({ carry: { first: index, last: index } })
+  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 (/\r/.test(node.text)) return failure('unspellable-character', 'a text node holds a carriage return CommonMark rewrites', path)
@@ -277,7 +284,7 @@ function emitMarkedRun(nodes: readonly AdfNode[], mark: AdfMark, depth: number,
   if (mark.type === 'backgroundColor' && context.flavour === 'plain') return emitHighlight(nodes, depth, range, context)
   const spelling = markSpelling(mark.type)
   if (spelling === undefined) return success({ carry: range })
-  const attributes = spellMarkAttributes(mark, spelling.attributes)
+  const attributes = spellMarkAttributes(mark, spelling)
   if (attributes === undefined) return success({ carry: range })
   if (spelling.kind === 'code') return emitCodeSpan(nodes, depth, range, path)
   if (spelling.kind === 'emphasis') return emitEmphasis(nodes, spelling.spelling, depth, range, context)
@@ -312,19 +319,20 @@ function emitHighlight(nodes: readonly AdfNode[], depth: number, range: NodeRang
   })
 }
 
+// Each node its own span: CommonMark reads two adjacent text nodes in one span back as one.
 function emitCodeSpan(nodes: readonly AdfNode[], depth: number, range: NodeRange, path: ConvertErrorPath): Result<Emission> {
-  let text = ''
+  const spans: string[] = []
   for (const node of nodes) {
-    if (node.type !== 'text' || nodeMarks(node).length !== depth + 1) return success({ carry: range })
+    if (node.type !== 'text' || nodeMarks(node).length !== depth + 1 || node.attrs !== undefined || emptyKeys(node).length > 0) return success({ carry: range })
-    if (typeof node.text !== 'string' || node.text === '') return failure('unsupported-node-shape', 'a text node holds text: this one has none', path)
+    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)
-    text += node.text
+    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)
+    spans.push(`${fence}${needsPadding(text) ? ` ${text} ` : text}${fence}`)
   }
-  if (/[\n\r]/.test(text)) return success({ carry: range })
+  return success({ segments: [syntax(spans.join(textBreakSpelling))] })
-  if (holdsNullCharacter(text)) return failure('unspellable-character', 'a code span holds a null character CommonMark replaces', path)
-  const fence = '`'.repeat(longestBacktickRun(text) + 1)
-  const padded = needsPadding(text) ? ` ${text} ` : text
-  return success({ segments: [syntax(`${fence}${padded}${fence}`)] })
 }
 
 function needsPadding(text: string): boolean {

src/markdown/emit/plain-reduction.test.ts

@@ -177,7 +177,7 @@ test('keeps the CommonMark blocks in their spelling and drops their attributes a
   assert.equal(plain(node('paragraph', localId, text('x')), node('heading', { level: 2, localId: '01a0d99b-1f57-7fec-94ae-50c2ee25c9de' }, text('h'))), 'x\n\n## h\n')
   assert.equal(plain({ attrs: localId, content: [said('q')], marks: [{ type: 'breakout' }], type: 'blockquote' }), '> q\n')
   assert.equal(plain(node('codeBlock', { language: 'ts', wrap: true }, text('a\r\nb\u0000'))), '```ts\na\nb\n```\n')
-  assert.equal(plain(node('codeBlock', { language: 'carry' }, text('a'), { type: 'hardBreak' }, text('b', strong))), '```\na\nb\n```\n')
+  assert.equal(plain(node('codeBlock', { language: 'adf:x' }, text('a'), { type: 'hardBreak' }, text('b', strong))), '```\na\nb\n```\n')
   assert.equal(plain(node('codeBlock', {})), '```\n```\n')
   assert.equal(plain(node('rule', { color: '#000' })), '---\n')
   assert.equal(plain(node('orderedList', { localId: '01a0d99b-1f58-7b95-829b-6f9860371d54', order: 3 }, item(said('c')))), '3. c\n')

src/markdown/emit/plain-reduction.ts

@@ -8,6 +8,7 @@ import { inlineNodeModel } from '../../adf/inline-nodes.ts'
 import { languageSlot } from '../code-language.ts'
 import { largestNesting } from '../../nesting.ts'
 import { taskMarker } from '../plain-conventions.ts'
+import { toEditorNormal } from '../../adf/editor-normal.ts'
 
 // depth: the level the node reduced stands at, counted as the emitter counts it.
 type Reduction = { depth: number; memo: SpellingMemo; path: ConvertErrorPath }
@@ -50,8 +51,9 @@ export function reduceToPlain(document: AdfDocument): Result<AdfDocument> {
   const fault = adfDocumentFault(document)
   if (fault !== undefined) return faulted(fault, [])
   if (document.version !== 1) return failure('unsupported-document-version', `no markdown spelling carries ADF version ${document.version}`, [])
-  const blocks = reduceBlocks(nodeContent(document), { depth: 0, memo: new Map(), path: [] })
+  // The plain flavour is lossy: it reads and writes editor-normal ADF, whose shapes CommonMark spells.
-  return blocks.ok ? success({ content: blocks.value, type: 'doc', version: 1 }) : blocks
+  const blocks = reduceBlocks(nodeContent(toEditorNormal(document)), { depth: 0, memo: new Map(), path: [] })
+  return blocks.ok ? success({ content: nodeContent(toEditorNormal({ content: blocks.value, type: 'doc', version: 1 })).slice(), type: 'doc', version: 1 }) : blocks
 }
 
 function reduceBlocks(nodes: readonly AdfNode[], reduction: Reduction): Result<AdfNode[]> {
@@ -262,7 +264,8 @@ function listItem(blocks: Result<AdfNode[]>): Result<AdfNode[]> {
 // A list item's first line reads as no rule and holds no line of spaces alone: the rule and the spaces give way.
 function itemOf(blocks: readonly AdfNode[]): AdfNode {
   const rules = blocks.findIndex((block) => block.type !== 'rule')
-  return { content: blankedCode(blocks.slice(rules === -1 ? blocks.length : rules)), type: 'listItem' }
+  const content = blankedCode(blocks.slice(rules === -1 ? blocks.length : rules))
+  return content.length === 0 ? { type: 'listItem' } : { content, type: 'listItem' }
 }
 
 function blankedCode(blocks: readonly AdfNode[]): AdfNode[] {

src/markdown/empty-keys.ts

@@ -0,0 +1,30 @@
+import type { DirectiveAttributes, DirectiveValue, Read } from './directive-syntax.ts'
+import type { EmptyKey } from '../adf/document.ts'
+import { emptyKeys } from '../adf/document.ts'
+import { unsupportedNodeShape } from './directive-syntax.ts'
+
+type EmptyKeysRead = { empty: ReadonlySet<EmptyKey>; rest: Map<string, DirectiveValue> }
+
+const emptyValue = 'empty'
+
+// spec/flavour.md, Attributes: no attribute value spells an empty object or array.
+export function spellEmptyKeys(held: Parameters<typeof emptyKeys>[0]): [string, string][] {
+  return emptyKeys(held).map((key) => [key, emptyValue])
+}
+
+export function spellsEmpty(value: DirectiveValue | undefined): boolean {
+  return value?.spelling === emptyValue
+}
+
+export function readEmptyKeys(attributes: DirectiveAttributes, keys: readonly EmptyKey[]): Read<EmptyKeysRead> {
+  const rest = new Map(attributes)
+  const empty = new Set<EmptyKey>()
+  for (const key of keys) {
+    const spelled = rest.get(key)
+    if (spelled === undefined) continue
+    if (!spellsEmpty(spelled)) return { fault: unsupportedNodeShape(`the reserved key ${key} reads ${key}=${emptyValue} alone: this one spells ${key}=${spelled.spelling}`) }
+    empty.add(key)
+    rest.delete(key)
+  }
+  return { value: { empty, rest } }
+}

src/markdown/mark-spellings.ts

@@ -7,6 +7,7 @@ import { holdsEntityReference } from './commonmark/entity-references.ts'
 import { isAutolink } from './commonmark/grammar.ts'
 import { isMarkType, markAttributes } from '../adf/mark-attributes.ts'
 import { nodeAttrs, nodeMarks } from '../adf/document.ts'
+import { spellEmptyKeys } from './empty-keys.ts'
 import { vocabularyPairs } from '../adf/attribute-vocabulary.ts'
 
 type Spelling = { kind: 'code' | 'directive' | 'link'; spelling?: undefined } | { kind: 'emphasis'; spelling: string }
@@ -55,7 +56,10 @@ function isBareLink(nodes: readonly AdfNode[], href: string, marksInside: number
   return nodes.length === 1 && node !== undefined && node.type === 'text' && node.text === href && nodeMarks(node).length === marksInside
 }
 
-export function spellMarkAttributes(mark: AdfMark, vocabulary: AttributeVocabulary): string | undefined {
+// `undefined` where the spelling holds no such attrs: only a directive spells attrs=empty.
-  const pairs = vocabularyPairs(nodeAttrs(mark), vocabulary, [])
+export function spellMarkAttributes(mark: AdfMark, spelling: MarkSpelling): string | undefined {
-  return pairs === undefined ? undefined : spellAttributes(spellVocabulary(pairs))
+  const pairs = vocabularyPairs(nodeAttrs(mark), spelling.attributes, [])
+  const empty = spellEmptyKeys(mark)
+  if (pairs === undefined || (empty.length > 0 && spelling.kind !== 'directive')) return undefined
+  return spellAttributes([...spellVocabulary(pairs), ...empty])
 }

src/markdown/opaque-carry.ts

@@ -1,32 +1,41 @@
 import type { AdfNode } from '../adf/document.ts'
 import type { DirectiveSpan, Read } from './directive-syntax.ts'
 import type { JsonSpelling } from '../canonical-json.ts'
+import type { JsonValue } from '../json-value.ts'
 import { failure, success, type ConvertErrorPath, type Result } from '../result.ts'
 import { fencedCodeBlock } from './commonmark/backtick-runs.ts'
+import { infoStringCarries } from './commonmark/grammar.ts'
 import { isAdfNode } from '../adf/document.ts'
 import { isJsonValue, nestingDepth, overNested } from '../json-value.ts'
 import { largestNesting } from '../nesting.ts'
 import { malformedDirective, readSoleStringAttribute, spellAttributes, spellInlineLeafDirective, spellStringAttribute, unsupportedNodeShape } from './directive-syntax.ts'
 import { serializeCanonicalJson } from '../canonical-json.ts'
 
+export const carryFencePrefix = 'adf:'
+
 export const carryName = 'carry'
 
 const jsonAttribute = 'json'
 
+// spec/flavour.md, The opaque carry: the info string names the type wherever it carries the type back.
 export function carriedBlock(node: AdfNode, path: ConvertErrorPath, depth: number): Result<{ headroom: number; text: string }> {
-  const json = carriedJson(node, 'two-space', path, largestNesting - depth)
+  const { type, ...untyped } = node
+  const named = infoStringCarries(type)
+  const json = carriedJson(node, named ? untyped : node, 'two-space', path, largestNesting - depth)
   if (!json.ok) return json
-  return success({ headroom: json.value.headroom, text: fencedCodeBlock(carryName, json.value.json) })
+  return success({ headroom: json.value.headroom, text: fencedCodeBlock(`${carryFencePrefix}${named ? type : ''}`, json.value.json) })
 }
 
 export function carriedInline(node: AdfNode, path: ConvertErrorPath): Result<string> {
-  const json = carriedJson(node, 'compact', path, largestNesting)
+  const json = carriedJson(node, node, 'compact', path, largestNesting)
   if (!json.ok) return json
   return success(spellInlineLeafDirective(carryName, spellAttributes([[jsonAttribute, spellStringAttribute(json.value.json)]])))
 }
 
-export function readCarriedBlock(body: string, depth: number): Read<AdfNode> {
+export function readCarriedBlock(type: string, body: string, depth: number): Read<AdfNode> {
-  return readCarriedJson(body, 'two-space', largestNesting - depth)
+  const read = readCarriedJson(body, 'two-space', largestNesting - depth, type)
+  if (read.fault !== undefined || type !== '' || !infoStringCarries(read.value.type)) return read
+  return { fault: unsupportedNodeShape(`the carry fence names a type its info string carries: spell it ${carryFencePrefix}${read.value.type}`) }
 }
 
 export function readCarriedInline(span: DirectiveSpan): Read<AdfNode> | undefined {
@@ -36,28 +45,38 @@ export function readCarriedInline(span: DirectiveSpan): Read<AdfNode> | undefine
   return readCarriedJson(spelled.value, 'compact', largestNesting)
 }
 
-function carriedJson(node: AdfNode, spelling: JsonSpelling, path: ConvertErrorPath, levels: number): Result<{ headroom: number; json: string }> {
+function carriedJson(node: AdfNode, spelled: object, spelling: JsonSpelling, path: ConvertErrorPath, levels: number): Result<{ headroom: number; json: string }> {
   const headroom = levels - nestingDepth(node)
-  if (!isJsonValue(node) || headroom < 0) {
+  if (!isJsonValue(spelled) || headroom < 0) {
     return failure('unsupported-nesting-depth', `a carried node's JSON nests deeper than the ${levels} levels its position leaves`, path)
   }
-  return success({ headroom, json: serializeCanonicalJson(node, spelling) })
+  return success({ headroom, json: serializeCanonicalJson(spelled, spelling) })
 }
 
-function readCarriedJson(raw: string, spelling: JsonSpelling, levels: number): Read<AdfNode> {
+// `type` is the one the fence's info string names, `undefined` for the inline carry.
+function readCarriedJson(raw: string, spelling: JsonSpelling, levels: number, type?: string): Read<AdfNode> {
   const parsed = parseJsonText(raw)
   if (parsed === undefined) return { fault: malformedDirective('the opaque carry holds invalid JSON') }
   const { value } = parsed
   if (!isJsonValue(value)) return { fault: unsupportedNodeShape('the opaque carry holds a number JSON cannot spell') }
-  if (overNested(value, levels)) {
+  const typed = type === undefined || type === '' ? { value } : typedValue(value, type)
+  if (typed.fault !== undefined) return typed
+  const held = typed.value
+  if (overNested(held, levels)) {
     return { fault: { code: 'unsupported-nesting-depth', message: `a carried node's JSON nests deeper than the ${levels} levels its position leaves` } }
   }
   if (serializeCanonicalJson(value, spelling) !== raw) {
     const shape = spelling === 'compact' ? 'compact, keys sorted' : 'two-space indent, keys sorted'
     return { fault: unsupportedNodeShape(`the opaque carry spells its node's JSON canonically: ${shape}`) }
   }
-  if (!isAdfNode(value)) return { fault: unsupportedNodeShape("the opaque carry holds one ADF node's JSON: this JSON is no ADF node") }
+  if (!isAdfNode(held)) return { fault: unsupportedNodeShape("the opaque carry holds one ADF node's JSON: this JSON is no ADF node") }
-  return { value }
+  return { value: held }
+}
+
+function typedValue(value: JsonValue, type: string): Read<JsonValue> {
+  if (value === null || typeof value !== 'object' || Array.isArray(value)) return { value }
+  if ('type' in value) return { fault: unsupportedNodeShape(`the ${carryFencePrefix}${type} fence names its node's type: this JSON holds a type as well`) }
+  return { value: { ...value, type } }
 }
 
 function parseJsonText(raw: string): { value: unknown } | undefined {

src/markdown/parse/directive-marks.ts

@@ -3,8 +3,9 @@ import type { ConvertFault } from '../../result.ts'
 import type { DirectiveAttributes } from '../directive-syntax.ts'
 import type { MarkSpelling } from '../mark-spellings.ts'
 import { directivePrefix } from '../directive-syntax.ts'
-import { failure, success, type ConvertErrorPath, type Result } from '../../result.ts'
+import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { markSpelling } from '../mark-spellings.ts'
+import { readEmptyKeys } from '../empty-keys.ts'
 import { readVocabulary } from './directive-attributes.ts'
 
 export function readDirectiveMark(name: string, attributes: DirectiveAttributes, path: ConvertErrorPath): Result<AdfMark> | undefined {
@@ -12,8 +13,11 @@ export function readDirectiveMark(name: string, attributes: DirectiveAttributes,
   if (spelling === undefined) return undefined
   const markdown = markdownForm(spelling)
   if (markdown !== undefined) return failure('unsupported-node-shape', `${name} is spelled ${markdown}, never as a directive`, path)
-  const attrs = readVocabulary(name, attributes, spelling.attributes, undefined, path)
+  const empty = readEmptyKeys(attributes, ['attrs'])
+  if (empty.fault !== undefined) return faulted(empty.fault, path)
+  const attrs = readVocabulary(name, empty.value.rest, spelling.attributes, undefined, path)
   if (!attrs.ok) return attrs
+  if (empty.value.empty.has('attrs')) return Object.keys(attrs.value).length === 0 ? success({ attrs: {}, type: name }) : failure('unsupported-node-shape', `${name} spells attrs=empty beside an attribute it holds`, path)
   return success(Object.keys(attrs.value).length === 0 ? { type: name } : { attrs: attrs.value, type: name })
 }
 

src/markdown/parse/directive-nodes.ts

@@ -1,4 +1,4 @@
-import type { AdfAttributes, AdfMark, AdfNode } from '../../adf/document.ts'
+import type { AdfAttributes, AdfMark, AdfNode, EmptyKey } from '../../adf/document.ts'
 import type { BlockNodeModel } from '../../adf/block-nodes.ts'
 import type { ConvertFault } from '../../result.ts'
 import type { DirectiveAttributes, DirectiveValue } from '../directive-syntax.ts'
@@ -7,15 +7,18 @@ import { attributeNestingMessage, nodeAttrs, nodeContent, nodeMarks } from '../.
 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'
-import { carryName } from '../opaque-carry.ts'
+import { carryFencePrefix, carryName } from '../opaque-carry.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { inlineMarkSpellingFault } from './directive-marks.ts'
 import { inlineNodeModel } from '../../adf/inline-nodes.ts'
+import { readEmptyKeys, spellsEmpty } from '../empty-keys.ts'
 import { readVocabulary } from './directive-attributes.ts'
 import { slotLineEndingFault } from '../directive-syntax.ts'
+import { textBreakName } from '../text-break.ts'
 import { textDirectiveName } from '../text-directive.ts'
 
-export type BlockDirectiveNode = { contentModel: BlockNodeModel['contentModel']; node: AdfNode }
+// `emptyContent` is whether the directive spells content=empty, which holds no body.
+export type BlockDirectiveNode = { contentModel: BlockNodeModel['contentModel']; emptyContent: boolean; node: AdfNode }
 
 export function readBlockDirectiveNode(
   name: string,
@@ -24,12 +27,15 @@ export function readBlockDirectiveNode(
   path: ConvertErrorPath,
 ): Result<BlockDirectiveNode> {
   if (name === carryName) {
-    return failure('malformed-directive', `the name ${carryName} is reserved for the opaque carry, whose block form is the ${carryName} fence`, path)
+    return failure('malformed-directive', `the name ${carryName} is reserved for the opaque carry, whose block form is the ${carryFencePrefix} fence`, path)
   }
   const model = blockNodeModel(name)
   if (model === undefined) return faulted(inlineSpellingFault(name) ?? unknownDirectiveFault(name), path)
   const argumentKey = blockArgument(name)
-  const rest = new Map(attributes)
+  const spelled = attributes.get(marksAttribute)
+  const empty = readEmptyKeys(attributes, spellsEmpty(spelled) ? ['attrs', 'content', 'marks'] : ['attrs', 'content'])
+  if (empty.fault !== undefined) return faulted(empty.fault, path)
+  const { rest } = empty.value
   rest.delete(marksAttribute)
   const elsewhere: Elsewhere | undefined = argumentKey === undefined ? undefined : { key: argumentKey, slot: 'argument' }
   const attrs = readVocabulary(name, rest, model.attributes, elsewhere, path)
@@ -38,10 +44,11 @@ export function readBlockDirectiveNode(
     if (argumentKey === undefined) return failure('unsupported-node-shape', `${name} takes no argument: this one spells one`, path)
     attrs.value[argumentKey] = argument
   }
-  const spelled = attributes.get(marksAttribute)
+  const marks: Result<AdfMark[] | undefined> = spelled === undefined || spellsEmpty(spelled) ? success(undefined) : readMarks(name, spelled, path)
-  const marks: Result<AdfMark[] | undefined> = spelled === undefined ? success(undefined) : readMarks(name, spelled, path)
   if (!marks.ok) return marks
-  return success({ contentModel: model.contentModel, node: namedNode(name, attrs.value, marks.value) })
+  const node = namedNode(name, attrs.value, marks.value, empty.value.empty, path)
+  if (!node.ok) return node
+  return success({ contentModel: model.contentModel, emptyContent: empty.value.empty.has('content'), node: node.value })
 }
 
 export function readInlineDirectiveNode(
@@ -55,7 +62,9 @@ export function readInlineDirectiveNode(
   const slot = model.textAttribute
   if (slot === undefined && content !== undefined) return failure('unsupported-node-shape', `${name} takes no content: this one holds some`, path)
   const elsewhere: Elsewhere | undefined = slot === undefined ? undefined : { key: slot, slot: 'content' }
-  const attrs = readVocabulary(name, attributes, model.attributes, elsewhere, path)
+  const empty = readEmptyKeys(attributes, ['attrs', 'content', 'marks'])
+  if (empty.fault !== undefined) return faulted(empty.fault, path)
+  const attrs = readVocabulary(name, empty.value.rest, model.attributes, elsewhere, path)
   if (!attrs.ok) return attrs
   if (slot !== undefined && content !== undefined) {
     const text = slotText(content)
@@ -66,14 +75,14 @@ export function readInlineDirectiveNode(
     if (spans !== undefined) return faulted(spans, path)
     attrs.value[slot] = text
   }
-  return success(namedNode(name, attrs.value, undefined))
+  return namedNode(name, attrs.value, undefined, empty.value.empty, path)
 }
 
 // A name the other position spells names that spelling, never the code a later MINOR may fill (docs/decisions.md §Which code a cause takes).
 function inlineSpellingFault(name: string): ConvertFault | undefined {
   const mark = inlineMarkSpellingFault(name)
   if (mark !== undefined) return mark
-  if (inlineNodeModel(name) === undefined && name !== textDirectiveName) return undefined
+  if (inlineNodeModel(name) === undefined && name !== textDirectiveName && name !== textBreakName) return undefined
   return { code: 'unsupported-node-shape', message: `${name} takes the inline form, ${directivePrefix}${name}{…}, never the block form` }
 }
 
@@ -100,7 +109,11 @@ function readMarks(type: string, spelled: DirectiveValue, path: ConvertErrorPath
   return success(marks)
 }
 
-function namedNode(type: string, attrs: AdfAttributes, marks: readonly AdfMark[] | undefined): AdfNode {
+function namedNode(type: string, attrs: AdfAttributes, marks: readonly AdfMark[] | undefined, empty: ReadonlySet<EmptyKey>, path: ConvertErrorPath): Result<AdfNode> {
-  const named = Object.keys(attrs).length === 0 ? { type } : { attrs, type }
+  const held = Object.keys(attrs).length > 0
-  return marks === undefined ? named : { ...named, marks: [...marks] }
+  if (held && empty.has('attrs')) return failure('unsupported-node-shape', `${type} spells attrs=empty beside an attribute it holds`, path)
+  const node: AdfNode = held || empty.has('attrs') ? { attrs, type } : { type }
+  if (empty.has('content')) node.content = []
+  if (marks !== undefined || empty.has('marks')) node.marks = [...(marks ?? [])]
+  return success(node)
 }

src/markdown/parse/inline-content.ts

@@ -10,16 +10,16 @@ import { commonMarkLink, linkHref } from '../mark-spellings.ts'
 import { delimiterFlags, matchEmphasis, runLength } from '../commonmark/emphasis-matching.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
 import { highlightDelimiter, highlightFlanking } from '../plain-conventions.ts'
+import { identicalMarks, nodeAttrs, nodeMarks } from '../../adf/document.ts'
 import { inlineNodeModel } from '../../adf/inline-nodes.ts'
-import { mergeAdjacentText, sameMarks } from '../../adf/editor-normal.ts'
 import { noSpans, readInlineDirective } from '../directive-syntax.ts'
-import { nodeAttrs, nodeMarks } from '../../adf/document.ts'
 import { normalizeLabel, readInlineTarget, readLabel } from '../commonmark/link-syntax.ts'
 import { openingLinkTakesDirective } from '../emit/inline-line.ts'
 import { readCarriedInline } from '../opaque-carry.ts'
 import { readDirectiveMark } from './directive-marks.ts'
 import { readInlineDirectiveNode } from './directive-nodes.ts'
 import { readTextDirective } from '../text-directive.ts'
+import { readsAsOne, textBreakName, textBreakSpelling } from '../text-break.ts'
 
 export type InlineContent = { carry?: undefined; image: AdfNode; nodes?: undefined } | { carry: boolean; image?: undefined; nodes: AdfNode[] }
 
@@ -31,8 +31,10 @@ type HighlightDelimiter = { closes: boolean; holder: AdfNode; index: number; lin
 
 type Pairing = EmphasisPairing<Run>
 
+// A carry piece holds a node whose marks are its own: an opaque carry, or an inline node spelling marks=empty.
 type Piece =
   | Bracket
+  | { kind: 'break' }
   | { kind: 'carry'; node: AdfNode }
   | { alt: string; kind: 'image'; node: AdfNode }
   | { kind: 'nodes'; nodes: AdfNode[] }
@@ -43,6 +45,8 @@ type Run = { canClose: boolean; canOpen: boolean; character: string; index: numb
 
 // `container` is `undefined` inside a directive's content slot, the emitter's `bracketed`.
 type Scan = {
+  // Nodes a carry piece restored: they never merge, and only identity tells a carried textBreak from the leaf.
+  carried: Set<AdfNode>
   container: LineContainer | undefined
   // Pieces below this have been walked for openers to deactivate: an image close folds the link-marked piece into alt text, leaving this the only record that the brackets around it are doomed.
   deactivatedBefore: number
@@ -58,7 +62,7 @@ type Scan = {
 
 type SlotContent = { carry: boolean; nodes: AdfNode[] }
 
-const carriedInMark = 'no mark spelling wraps an opaque carry: the carried node restores exactly, marks included'
+const carriedInMark = 'no mark spelling wraps an opaque carry or an inline node spelling marks=empty: its marks are its own'
 const editorHighlight: AdfMark = { attrs: { color: '#f8e6a0' }, type: 'backgroundColor' }
 const hreflessLink = 'the link mark spells its href: this one spells none'
 const imageAlone = 'an image fits only as a paragraph of its own: this one sits inside other content'
@@ -66,11 +70,11 @@ const linkInLink = 'no link wraps a link: the [content] this one marks already h
 const spellableLink = 'link takes the directive form only where CommonMark cannot spell it: this one it can, as [text](url "title") or <url>'
 
 export function parseInlineContent(source: string, definitions: LinkDefinitions, path: ConvertErrorPath, container: LineContainer, flavour: Flavour): Result<InlineContent> {
-  return parseInline(source, definitions, path, container, noSpans, flavour === 'plain')
+  return parseInline(source, { carried: new Set(), container, definitions, highlights: flavour === 'plain', path, spans: noSpans })
 }
 
-function parseInline(source: string, definitions: LinkDefinitions, path: ConvertErrorPath, container: LineContainer | undefined, spans: NestedSpans, highlights: boolean): Result<InlineContent> {
+function parseInline(source: string, context: Pick<Scan, 'carried' | 'container' | 'definitions' | 'highlights' | 'path' | 'spans'>): Result<InlineContent> {
-  const scan: Scan = { container, deactivatedBefore: 0, definitions, highlights, openingSpellableLink: false, path, pending: '', pieces: [], source, spans }
+  const scan: Scan = { ...context, deactivatedBefore: 0, openingSpellableLink: false, pending: '', pieces: [], source }
   let index = 0
   while (index < source.length) {
     switch (source.charAt(index)) {
@@ -103,7 +107,7 @@ function parseInline(source: string, definitions: LinkDefinitions, path: Convert
         index = readCharacter(scan, index)
     }
   }
-  flush(scan, container !== undefined)
+  flush(scan, scan.container !== undefined)
   return assemble(scan)
 }
 
@@ -205,8 +209,9 @@ function directivePiece(scan: Scan, span: DirectiveSpan, index: number): Result<
   const carried = readCarriedInline(span)
   if (carried !== undefined) {
     if (carried.fault !== undefined) return faulted(carried.fault, scan.path)
-    return success({ kind: 'carry', node: carried.value })
+    return success(carryPiece(scan, carried.value))
   }
+  if (span.name === textBreakName) return span.content === undefined && span.attributes.size === 0 ? success({ kind: 'break' }) : failure('unsupported-node-shape', `${textBreakName} spells the bare leaf form, ${textBreakSpelling}: this one spells more`, scan.path)
   const text = readTextDirective(span)
   if (text?.fault !== undefined) return faulted(text.fault, scan.path)
   if (text !== undefined) return success({ kind: 'nodes', nodes: [{ text: text.value, type: 'text' }] })
@@ -216,7 +221,12 @@ function directivePiece(scan: Scan, span: DirectiveSpan, index: number): Result<
   if (mark !== undefined) return mark.ok ? directiveMarkPiece(scan, span.name, mark.value, slot.value, index) : mark
   const node = readInlineDirectiveNode(span.name, span.attributes, slot.value?.nodes, scan.path)
   if (!node.ok) return node
-  return success({ kind: 'nodes', nodes: [node.value] })
+  return success(node.value.marks === undefined ? { kind: 'nodes', nodes: [node.value] } : carryPiece(scan, node.value))
+}
+
+function carryPiece(scan: Scan, node: AdfNode): Piece {
+  scan.carried.add(node)
+  return { kind: 'carry', node }
 }
 
 function directiveMarkPiece(scan: Scan, name: string, mark: AdfMark, slot: SlotContent | undefined, index: number): Result<Piece> {
@@ -242,7 +252,7 @@ function refuseLinkDirective(scan: Scan, mark: AdfMark, nodes: readonly AdfNode[
 
 function slotContent(scan: Scan, span: DirectiveSpan): Result<SlotContent | undefined> {
   if (span.content === undefined) return success(undefined)
-  const parsed = parseInline(span.content, scan.definitions, scan.path, undefined, span.spans, false)
+  const parsed = parseInline(span.content, { ...scan, container: undefined, highlights: false, spans: span.spans })
   if (!parsed.ok) return parsed
   if (parsed.value.image !== undefined) return failure('unmappable-image', imageAlone, scan.path)
   return success(parsed.value)
@@ -262,7 +272,8 @@ function assemble(scan: Scan): Result<InlineContent> {
   const only = scan.pieces[0]
   if (scan.pieces.length === 1 && only?.kind === 'image') return success({ image: only.node })
   if (holdsImage(scan.pieces)) return failure('unmappable-image', imageAlone, scan.path)
-  const nodes = resolveNodes(scan.pieces, scan.path, true)
+  const resolved = resolveNodes(scan.pieces, scan, true)
+  const nodes = resolved.ok && scan.container !== undefined ? partText(resolved.value, scan) : resolved
   if (!nodes.ok) return nodes
   if (scan.openingSpellableLink) {
     const takesDirective = openingLinkTakesDirective(nodes.value, scan.path)
@@ -272,6 +283,27 @@ function assemble(scan: Scan): Result<InlineContent> {
   return success({ carry: holdsCarry(scan.pieces), nodes: nodes.value })
 }
 
+// spec/flavour.md, Inline nodes: the leaf builds no node, so only the pair it parts spells it.
+function partText(nodes: readonly AdfNode[], scan: Scan): Result<AdfNode[]> {
+  const parted: AdfNode[] = []
+  for (const [index, node] of nodes.entries()) {
+    if (!isTextBreak(node, scan.carried)) {
+      parted.push(node)
+      continue
+    }
+    const previous = nodes[index - 1]
+    const next = nodes[index + 1]
+    if (previous === undefined || next === undefined || scan.carried.has(previous) || scan.carried.has(next) || !readsAsOne(previous, next)) {
+      return failure('unsupported-node-shape', `${textBreakName} parts two text nodes CommonMark reads back as one: this one parts something else`, scan.path)
+    }
+  }
+  return success(parted)
+}
+
+function isTextBreak(node: AdfNode, carried: ReadonlySet<AdfNode>): boolean {
+  return node.type === textBreakName && !carried.has(node)
+}
+
 function holdsCarry(pieces: readonly Piece[]): boolean {
   return pieces.some((piece) => piece.kind === 'carry')
 }
@@ -383,7 +415,7 @@ function closeLink(scan: Scan, at: number, inner: readonly Piece[], definition:
   }
   if (holdsImage(inner)) return failure('unmappable-image', imageAlone, scan.path)
   if (holdsCarry(inner)) return failure('unsupported-node-shape', carriedInMark, scan.path)
-  const resolved = resolveNodes(inner, scan.path, true)
+  const resolved = resolveNodes(inner, scan, true)
   if (!resolved.ok) return resolved
   const nodes = resolved.value
   // An empty link text gives the mark no node to ride, so the brackets stay text.
@@ -411,7 +443,7 @@ function truncatePieces(scan: Scan, to: number): void {
 
 function closeImage(scan: Scan, at: number, inner: readonly Piece[], definition: LinkDefinition): Result<null> {
   if (definition.title !== undefined) return failure('unmappable-image', 'no media node carries a link title', scan.path)
-  const resolved = imageAlt(inner, scan.path)
+  const resolved = imageAlt(inner, scan)
   if (!resolved.ok) return resolved
   const alt = resolved.value
   const attrs = alt === '' ? { type: 'external', url: definition.destination } : { alt, type: 'external', url: definition.destination }
@@ -420,9 +452,10 @@ function closeImage(scan: Scan, at: number, inner: readonly Piece[], definition:
   return success(null)
 }
 
-function imageAlt(inner: readonly Piece[], path: ConvertErrorPath): Result<string> {
+function imageAlt(inner: readonly Piece[], scan: Scan): Result<string> {
-  const nodes = resolveNodes(inner, path, false)
+  const nodes = resolveNodes(inner, scan, false)
   if (!nodes.ok) return nodes
+  if (nodes.value.some((node) => isTextBreak(node, scan.carried))) return failure('unsupported-node-shape', `${textBreakName} parts two text nodes: an image description holds plain text`, scan.path)
   return success(nodes.value.map(altText).join(''))
 }
 
@@ -435,20 +468,35 @@ function altText(node: AdfNode): string {
 }
 
 // An image's alt text is plain, so `highlights` is off there and every `==` stays text.
-function resolveNodes(pieces: readonly Piece[], path: ConvertErrorPath, highlights: boolean): Result<AdfNode[]> {
+function resolveNodes(pieces: readonly Piece[], scan: Scan, highlights: boolean): Result<AdfNode[]> {
   const nodes = pieces.map(pieceNodes)
   const runs = delimiterRuns(pieces)
   const pairings = matchEmphasis(runs)
   writeUnpaired(nodes, runs, pairings)
-  if (!markPairings(pieces, nodes, pairings)) return failure('unsupported-node-shape', carriedInMark, path)
+  if (!markPairings(pieces, nodes, pairings)) return failure('unsupported-node-shape', carriedInMark, scan.path)
   markHighlights(pieces, nodes, highlights ? pairedHighlights(pieces, nodes) : [])
-  return success(mergeAdjacentText(nodes.flat()))
+  return success(mergeText(nodes.flat(), scan.carried))
+}
+
+function mergeText(nodes: readonly AdfNode[], carried: ReadonlySet<AdfNode>): AdfNode[] {
+  const merged: AdfNode[] = []
+  for (const node of nodes) {
+    const previous = merged[merged.length - 1]
+    if (previous !== undefined && !carried.has(previous) && !carried.has(node) && readsAsOne(previous, node)) {
+      merged[merged.length - 1] = { ...previous, text: `${previous.text ?? ''}${node.text ?? ''}` }
+      continue
+    }
+    merged.push(node)
+  }
+  return merged
 }
 
 // Only `imageAlt` reaches the image arm: everywhere else an image amid other content is refused first.
 // A highlight delimiter holds an empty text node until it pairs, so the emphasis around it marks it.
 function pieceNodes(piece: Piece): AdfNode[] {
   switch (piece.kind) {
+    case 'break':
+      return [{ type: textBreakName }]
     case 'carry':
       return [piece.node]
     case 'highlight':
@@ -531,7 +579,7 @@ function pairedHighlights(pieces: readonly Piece[], nodes: readonly AdfNode[][])
     let candidate = found[closer]
     while (candidate !== undefined && (!candidate.closes || candidate.position < earliest)) candidate = found[(closer += 1)]
     if (candidate === undefined) break
-    if (candidate.line !== opener.line || !sameMarks(opener.holder, candidate.holder)) continue
+    if (candidate.line !== opener.line || !identicalMarks(opener.holder, candidate.holder)) continue
     paired.push({ closer: candidate.index, opener: opener.index })
     resume = candidate.position + highlightDelimiter.length
   }

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

@@ -84,9 +84,21 @@ function table(...rows: AdfNode[]): AdfNode {
   return { content: rows, type: 'table' }
 }
 
-test('builds an empty document from input holding no block', () => {
+test('builds an empty document from input holding no block, and one holding no content key from the doc directive alone', () => {
-  assert.deepEqual(markdownToAdf(''), { ok: true, value: { type: 'doc', version: 1 } })
+  assert.deepEqual(markdownToAdf(''), { ok: true, value: { content: [], type: 'doc', version: 1 } })
-  assert.deepEqual(content(markdownToAdf('\n \n\t\n')), [])
+  assert.deepEqual(markdownToAdf('\n \n\t\n'), { ok: true, value: { content: [], type: 'doc', version: 1 } })
+  assert.deepEqual(markdownToAdf('!adf:doc {content=none}\n'), { ok: true, value: { type: 'doc', version: 1 } })
+  assert.deepEqual(markdownToAdf('\n!adf:doc {content=none}\n\n'), { ok: true, value: { type: 'doc', version: 1 } })
+  const form = 'unsupported-node-shape: doc spells the one form !adf:doc {content=none}: this one spells another'
+  assert.equal(content(markdownToAdf('!adf:doc\n')), form)
+  assert.equal(content(markdownToAdf('!adf:doc x {content=none}\n')), form)
+  assert.equal(content(markdownToAdf('!adf:doc {content=empty}\n')), form)
+  assert.equal(content(markdownToAdf('!adf:doc {content="none"}\n')), form)
+  const alone = 'unsupported-node-shape: !adf:doc {content=none} spells a whole document holding no content key, alone: this one stands among other blocks'
+  assert.equal(content(markdownToAdf('x\n\n!adf:doc {content=none}\n')), alone)
+  assert.equal(content(markdownToAdf('!adf:panel info\n!adf:doc {content=none}\n!adf:/panel\n')), alone)
+  assert.equal(content(markdownToAdf('!adf:doc\n!adf:/doc\n')), 'malformed-directive: doc takes no body, so no !adf:/doc closes it; \\!adf: keeps the prefix literal')
+  assert.equal(content(markdownToAdf('a !adf:doc{content=none}\n')), 'unsupported-node-shape: doc takes the block form, !adf:doc, never the inline form')
 })
 
 test('builds one paragraph from the lines a blank line does not part', () => {
@@ -153,7 +165,7 @@ test('names the slot a codeBlock spells its language outside of', () => {
   const slot = 'unsupported-node-shape: codeBlock spells its language in the fence info string, or in the attribute where no info string carries it back'
   assert.equal(content(markdownToAdf('!adf:codeBlock {language=rust wrap=true}\n```\nx\n```\n!adf:/codeBlock\n')), slot)
   assert.equal(content(markdownToAdf('!adf:codeBlock {language=rust}\n```sql\nx\n```\n!adf:/codeBlock\n')), slot)
-  assert.equal(content(markdownToAdf('!adf:codeBlock {wrap=true}\n```carry\nx\n```\n!adf:/codeBlock\n')), slot)
+  assert.equal(content(markdownToAdf('!adf:codeBlock {wrap=true}\n```adf:x\nx\n```\n!adf:/codeBlock\n')), slot)
   assert.equal(content(markdownToAdf('!adf:codeBlock {wrap=true}\n```a\\b\nx\n```\n!adf:/codeBlock\n')), slot)
 })
 
@@ -343,18 +355,26 @@ test('names the position a directive name the other one spells belongs to', () =
 })
 
 test('names the reserved carry name a block directive spells', () => {
-  const reserved = 'malformed-directive: the name carry is reserved for the opaque carry, whose block form is the carry fence'
+  const reserved = 'malformed-directive: the name carry is reserved for the opaque carry, whose block form is the adf: fence'
   assert.equal(content(markdownToAdf('!adf:carry\n')), reserved)
   assert.equal(content(markdownToAdf('!adf:carry\nx\n!adf:/carry\n')), reserved)
   assert.deepEqual(content(markdownToAdf('```adf\nx\n```\n')), [{ attrs: { language: 'adf' }, content: [text('x')], type: 'codeBlock' }])
+  assert.deepEqual(content(markdownToAdf('```carry\nx\n```\n')), [{ attrs: { language: 'carry' }, content: [text('x')], type: 'codeBlock' }])
 })
 
 const carried = '!adf:carry{json="{\\"type\\":\\"placeholder\\"}"}'
 
-test('reads the carry fence back to the node its JSON holds', () => {
+test('reads the carry fence back to the node its info string names and its JSON holds', () => {
-  assert.deepEqual(content(markdownToAdf('```carry\n{\n  "attrs": {\n    "url": "https://example.com/x"\n  },\n  "type": "blockCard"\n}\n```\n')), [
+  assert.deepEqual(content(markdownToAdf('```adf:blockCard\n{\n  "attrs": {\n    "url": "https://example.com/x"\n  }\n}\n```\n')), [
     { attrs: { url: 'https://example.com/x' }, type: 'blockCard' },
   ])
+  assert.deepEqual(content(markdownToAdf('```adf:\n{\n  "type": "a`b"\n}\n```\n')), [{ type: 'a`b' }])
+  assert.equal(
+    content(markdownToAdf('```adf:blockCard\n{\n  "type": "blockCard"\n}\n```\n')),
+    "unsupported-node-shape: the adf:blockCard fence names its node's type: this JSON holds a type as well",
+  )
+  assert.equal(content(markdownToAdf('```adf:\n{\n  "type": "blockCard"\n}\n```\n')), 'unsupported-node-shape: the carry fence names a type its info string carries: spell it adf:blockCard')
+  assert.equal(content(markdownToAdf('```adf:\n{}\n```\n')), "unsupported-node-shape: the opaque carry holds one ADF node's JSON: this JSON is no ADF node")
 })
 
 test('reads the inline carry back to the node its json attribute holds', () => {
@@ -365,22 +385,22 @@ test('reads the inline carry back to the node its json attribute holds', () => {
 
 test('names the invalid JSON no opaque carry holds', () => {
   const invalid = 'malformed-directive: the opaque carry holds invalid JSON'
-  assert.equal(content(markdownToAdf('```carry\n{"type":\n```\n')), invalid)
+  assert.equal(content(markdownToAdf('```adf:x\n{"attrs":\n```\n')), invalid)
-  assert.equal(content(markdownToAdf('```carry\n```\n')), invalid)
+  assert.equal(content(markdownToAdf('```adf:x\n```\n')), invalid)
   assert.equal(content(markdownToAdf('!adf:carry{json="{"}\n')), invalid)
   assert.equal(content(markdownToAdf('!adf:carry{json=abc}\n')), invalid)
 })
 
 test('names the canonical spelling a carried JSON reads alone', () => {
   const canonically = "unsupported-node-shape: the opaque carry spells its node's JSON canonically: "
-  assert.equal(content(markdownToAdf('```carry\n{"type":"blockCard"}\n```\n')), `${canonically}two-space indent, keys sorted`)
+  assert.equal(content(markdownToAdf('```adf:blockCard\n{"attrs":{}}\n```\n')), `${canonically}two-space indent, keys sorted`)
   assert.equal(content(markdownToAdf('!adf:carry{json="{\\"type\\": \\"blockCard\\"}"}\n')), `${canonically}compact, keys sorted`)
   assert.equal(content(markdownToAdf('!adf:carry{json="{\\"type\\":\\"blockCard\\",\\"attrs\\":{}}"}\n')), `${canonically}compact, keys sorted`)
 })
 
 test('names the node JSON an opaque carry restores alone', () => {
   const node = "unsupported-node-shape: the opaque carry holds one ADF node's JSON: this JSON is no ADF node"
-  assert.equal(content(markdownToAdf('```carry\n[]\n```\n')), node)
+  assert.equal(content(markdownToAdf('```adf:x\n[]\n```\n')), node)
   assert.equal(content(markdownToAdf('!adf:carry{json=null}\n')), node)
   assert.equal(content(markdownToAdf('!adf:carry{json="{\\"kind\\":\\"x\\"}"}\n')), node)
 })
@@ -394,7 +414,7 @@ test('names the shape the inline carry reads alone', () => {
 
 test('holds a carried JSON value to the nesting its position leaves', () => {
   const nested = (levels: number): string => `${'['.repeat(levels)}${']'.repeat(levels)}`
-  const fence = (prefix: string, levels: number): string => `${prefix}\`\`\`carry\n${prefix}${nested(levels)}\n${prefix}\`\`\`\n`
+  const fence = (prefix: string, levels: number): string => `${prefix}\`\`\`adf:x\n${prefix}${nested(levels)}\n${prefix}\`\`\`\n`
   const deeper = (levels: number): string => `unsupported-nesting-depth: a carried node's JSON nests deeper than the ${levels} levels its position leaves`
   assert.equal(content(markdownToAdf(`!adf:carry{json="${nested(largestNesting + 2)}"}\n`)), deeper(largestNesting))
   assert.equal(
@@ -407,11 +427,11 @@ test('holds a carried JSON value to the nesting its position leaves', () => {
 test('names the number no JSON spelling carries in an opaque carry', () => {
   const named = 'unsupported-node-shape: the opaque carry holds a number JSON cannot spell'
   assert.equal(content(markdownToAdf('!adf:carry{json="{\\"attrs\\":{\\"width\\":1e999},\\"type\\":\\"blockCard\\"}"}\n')), named)
-  assert.equal(content(markdownToAdf('```carry\n1e999\n```\n')), named)
+  assert.equal(content(markdownToAdf('```adf:x\n1e999\n```\n')), named)
 })
 
 test('names the mark spelling no opaque carry sits inside', () => {
-  const named = 'unsupported-node-shape: no mark spelling wraps an opaque carry: the carried node restores exactly, marks included'
+  const named = 'unsupported-node-shape: no mark spelling wraps an opaque carry or an inline node spelling marks=empty: its marks are its own'
   assert.equal(content(markdownToAdf(`_a ${carried} b_\n`)), named)
   assert.equal(content(markdownToAdf(`**${carried}**\n`)), named)
   assert.equal(content(markdownToAdf(`~~a ${carried}~~\n`)), named)
@@ -454,7 +474,9 @@ test('names the marks key no marks array reads back from', () => {
   assert.equal(content(markdownToAdf('!adf:rule {marks="[1]"}\n')), named)
   assert.equal(content(markdownToAdf('!adf:rule {marks="{}"}\n')), named)
   assert.equal(content(markdownToAdf('!adf:rule {marks=x}\n')), named)
-  assert.equal(content(markdownToAdf('!adf:rule {marks="[{\\"attrs\\":{},\\"type\\":\\"em\\"}]"}\n')), named)
+  assert.equal(content(markdownToAdf('!adf:rule {marks="[{\\"type\\":\\"em\\",\\"attrs\\":{}}]"}\n')), named)
+  assert.deepEqual(content(markdownToAdf('!adf:rule {marks="[{\\"attrs\\":{},\\"type\\":\\"em\\"}]"}\n')), [{ marks: [{ attrs: {}, type: 'em' }], type: 'rule' }])
+  assert.deepEqual(content(markdownToAdf('!adf:rule {marks=empty}\n')), [{ marks: [], type: 'rule' }])
 })
 
 test('names the attribute a node holds no reading for', () => {
@@ -487,7 +509,8 @@ test('names the argument and the body a node takes no reading for', () => {
   assert.equal(content(markdownToAdf('!adf:rule x\n')), 'unsupported-node-shape: rule takes no argument: this one spells one')
   assert.equal(content(markdownToAdf('!adf:paragraph\nOne.\n\nTwo.\n!adf:/paragraph\n')), 'unsupported-node-shape: paragraph takes one paragraph as its body: this body is not one')
   assert.equal(content(markdownToAdf('!adf:paragraph\n---\n!adf:/paragraph\n')), 'unsupported-node-shape: paragraph takes one paragraph as its body: this body is not one')
-  assert.equal(content(markdownToAdf('!adf:codeBlock {wrap=true}\nx\n!adf:/codeBlock\n')), 'unsupported-node-shape: codeBlock takes one code block as its body: this body is not one')
+  assert.equal(content(markdownToAdf('!adf:codeBlock {wrap=true}\nx\n!adf:/codeBlock\n')), 'unsupported-node-shape: codeBlock takes code blocks as its body: this body holds another block')
+  assert.equal(content(markdownToAdf('!adf:codeBlock {wrap=true}\n!adf:/codeBlock\n')), 'unsupported-node-shape: codeBlock takes code blocks as its body: this body holds none')
   assert.equal(content(markdownToAdf('!adf:paragraph\n![a](/u)\n!adf:/paragraph\n')), 'unmappable-image: no ADF node carries an image inside a paragraph')
   assert.equal(content(markdownToAdf('Part !adf:date[now]{timestamp=1}.\n')), 'unsupported-node-shape: date takes no content: this one holds some')
 })
@@ -545,7 +568,7 @@ test('names the line and the offset in the input a refusal sits at, the innermos
   assert.deepEqual(position(markdownToAdf('- Part.\n- a <span>b</span>\n')), { line: 2, offset: 8 })
   assert.deepEqual(position(markdownToAdf('Part.\n\n!adf:panel info\nMore.\n')), { line: 3, offset: 7 })
   assert.deepEqual(position(markdownToAdf('x\n\na <span>b</span>\n===\n')), { line: 3, offset: 3 })
-  assert.deepEqual(position(markdownToAdf('x\n\n```carry\n{\n```\n')), { line: 3, offset: 3 })
+  assert.deepEqual(position(markdownToAdf('x\n\n```adf:x\n{\n```\n')), { line: 3, offset: 3 })
   assert.deepEqual(position(markdownToAdf('x\n\n| a |\n')), { line: 3, offset: 3 })
   assert.deepEqual(position(markdownToAdf('a\nb <span>c</span>\n')), { line: 1, offset: 0 })
   assert.deepEqual(position(markdownToAdf('Part.\r\n\r\n<div>\r\n')), { line: 3, offset: 9 })

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

@@ -5,14 +5,14 @@ import type { ConvertFault } from '../../result.ts'
 import type { Flavour } from '../plain-conventions.ts'
 import type { LineContainer } from '../line-container.ts'
 import type { LinkDefinitions } from './inline-content.ts'
-import { carryName, readCarriedBlock } from '../opaque-carry.ts'
+import { carryFencePrefix, readCarriedBlock } from '../opaque-carry.ts'
 import { commonMarkSpelling, type SpellingMemo } from '../emit/adf-to-markdown.ts'
+import { documentName, documentSpelling, listBreakName, listBreakSpelling } from '../block-directive.ts'
 import { failure, faulted, positioned, success, type ConvertErrorPath, type ParseError, type Result, type SourcePosition } from '../../result.ts'
 import { inlineLeaves } from '../emit/plain-inline.ts'
 import { languageSlot } from '../code-language.ts'
 import { largestNesting } from '../../nesting.ts'
 import { leadingMarker, readAlertMarker, readTaskMarker } from '../plain-conventions.ts'
-import { listBreakName, listBreakSpelling } from '../block-directive.ts'
 import { mintTaskIds } from './task-ids.ts'
 import { nodeAttrs, nodeContent } from '../../adf/document.ts'
 import { parseBlocks } from './blocks.ts'
@@ -39,10 +39,15 @@ export function plainMarkdownToAdf(markdown: string): Result<AdfDocument, ParseE
 
 function readDocument(markdown: string, flavour: Flavour): Result<AdfDocument, ParseError> {
   const parsed = parseBlocks(markdown)
+  const [only] = parsed.blocks
+  if (parsed.blocks.length === 1 && only?.kind === 'directive' && only.name === documentName) {
+    const fault = documentFault(only)
+    return fault === undefined ? success({ type: 'doc', version: 1 }) : positioned(faulted(fault, []), only.position)
+  }
   const reading: Reading = { carried: new Set(), definitions: parsed.definitions, flavour, inExpand: false, memo: new Map() }
   const content = positioned(readBlocks(parsed.blocks, reading, [], 0), documentStart)
   if (!content.ok) return content
-  const document: AdfDocument = content.value.length === 0 ? { type: 'doc', version: 1 } : { content: content.value, type: 'doc', version: 1 }
+  const document: AdfDocument = { content: content.value, type: 'doc', version: 1 }
   if (flavour === 'plain') mintTaskIds(document, markdown, reading.carried)
   return success(document)
 }
@@ -52,6 +57,10 @@ function readBlocks(blocks: readonly Block[], reading: Reading, path: ConvertErr
   const content: AdfNode[] = []
   for (const [index, block] of blocks.entries()) {
     const nodePath = [...path, 'content', content.length]
+    if (block.kind === 'directive' && block.name === documentName) {
+      const fault = documentFault(block) ?? unsupportedNodeShape(`${documentSpelling} spells a whole document holding no content key, alone: this one stands among other blocks`)
+      return positioned(faulted(fault, nodePath), block.position)
+    }
     if (block.kind === 'directive' && block.name === listBreakName) {
       const fault = listBreakFault(block, blocks[index - 1], blocks[index + 1])
       if (fault !== undefined) return positioned(faulted(fault, nodePath), block.position)
@@ -73,6 +82,12 @@ function listBreakFault(block: DirectiveBlock, previous: Block | undefined, next
   return previous.kind === next?.kind ? undefined : partsFault()
 }
 
+function documentFault(block: DirectiveBlock): ConvertFault | undefined {
+  const content = block.attributes.get('content')
+  if (block.argument === undefined && block.attributes.size === 1 && content?.spelling === 'none') return undefined
+  return unsupportedNodeShape(`${documentName} spells the one form ${documentSpelling}: this one spells another`)
+}
+
 function partsFault(): ConvertFault {
   return unsupportedNodeShape(`${listBreakName} parts two adjacent lists of one type: this one parts something else`)
 }
@@ -214,24 +229,33 @@ function directiveNode(block: DirectiveBlock, reading: Reading, path: ConvertErr
 }
 
 function directiveBody(read: BlockDirectiveNode, blocks: Block[] | undefined, reading: Reading, path: ConvertErrorPath, depth: number): Result<AdfNode> {
-  const { contentModel, node } = read
+  const { contentModel, emptyContent, node } = read
   if (blocks === undefined) return success(node)
+  if (emptyContent) return blocks.length === 0 ? success(node) : failure('unsupported-node-shape', `${node.type} spells content=empty, which holds no body: this one holds one`, path)
   if (contentModel === 'code') return codeDirectiveNode(node, blocks, path)
   if (contentModel === 'inline') return inlineBodyNode(node, blocks, reading, path)
   return containerNode(node, blocks, reading, path, depth)
 }
 
+// spec/flavour.md, The CommonMark blocks: one fence per text node, every fence carrying the one language.
 function codeDirectiveNode(node: AdfNode, blocks: readonly Block[], path: ConvertErrorPath): Result<AdfNode> {
-  const only = blocks.length === 1 ? blocks[0] : undefined
+  const fences: Extract<Block, { kind: 'code' }>[] = []
-  if (only?.kind !== 'code') return failure('unsupported-node-shape', `${node.type} takes one code block as its body: this body is not one`, path)
+  for (const block of blocks) {
+    if (block.kind !== 'code') return failure('unsupported-node-shape', `${node.type} takes code blocks as its body: this body holds another block`, path)
+    fences.push(block)
+  }
+  const [first] = fences
+  if (first === undefined) return failure('unsupported-node-shape', `${node.type} takes code blocks as its body: this body holds none`, path)
+  if (fences.some((fence) => fence.language !== first.language)) return failure('unsupported-node-shape', `${node.type} holds one language, so its fences carry one info string: these differ`, path)
+  if (fences.length > 1 && fences.some((fence) => fence.text === '')) return failure('unsupported-node-shape', `a fence beside another spells a text node, which holds text: this one is empty`, path)
   const attribute = nodeAttrs(node)['language']
-  const fromFence = only.language !== ''
+  const fromFence = first.language !== ''
-  const slot = languageSlot(fromFence ? only.language : attribute)
+  const slot = languageSlot(fromFence ? first.language : attribute)
   if ((slot.kind === 'fence') !== fromFence || (fromFence && attribute !== undefined)) {
     return failure('unsupported-node-shape', `${node.type} spells its language in the fence info string, or in the attribute where no info string carries it back`, path)
   }
-  const spelled = fromFence ? { ...node, attrs: { ...node.attrs, language: only.language } } : node
+  const spelled = fromFence ? { ...node, attrs: { ...node.attrs, language: first.language } } : node
-  return success(withContent(spelled, only.text === '' ? [] : [{ text: only.text, type: 'text' }]))
+  return success(withContent(spelled, first.text === '' ? [] : fences.map((fence): AdfNode => ({ text: fence.text, type: 'text' }))))
 }
 
 function tableNode(rows: readonly string[][], reading: Reading, path: ConvertErrorPath): Result<AdfNode> {
@@ -278,8 +302,8 @@ function listNode(node: AdfNode, items: readonly Block[][], reading: Reading, pa
 }
 
 function codeBlockNode(language: string, text: string, reading: Reading, path: ConvertErrorPath, depth: number): Result<AdfNode> {
-  if (language === carryName) {
+  if (language.startsWith(carryFencePrefix)) {
-    const carried = readCarriedBlock(text, depth)
+    const carried = readCarriedBlock(language.slice(carryFencePrefix.length), text, depth)
     if (carried.fault !== undefined) return faulted(carried.fault, path)
     reading.carried.add(carried.value)
     return success(carried.value)

src/markdown/text-break.ts

@@ -0,0 +1,16 @@
+import type { AdfNode } from '../adf/document.ts'
+import { identicalMarks } from '../adf/document.ts'
+import { spellInlineLeafDirective } from './directive-syntax.ts'
+
+export const textBreakName = 'textBreak'
+
+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(previous, node)
+}
+
+function spelledAsText(node: AdfNode): boolean {
+  return node.type === 'text' && node.attrs === undefined && node.content === undefined && node.marks?.length !== 0
+}