From 6df17a7069a1670e29a26a9313d79781b67536bf Mon Sep 17 00:00:00 2001
From: Lilleman auf Larv <lilleman@larvit.se>
Date: Sat, 3 Oct 2026 15:50:24 +0200
Subject: [PATCH] Gather the plain flavour's code in markdown/plain/

---
 docs/decisions.md                                         | 7 +++++--
 src/conformance/adf-property.test.ts                      | 4 ++--
 src/conformance/property-harness.ts                       | 2 +-
 src/index.ts                                              | 2 +-
 src/markdown/emit/adf-to-markdown.ts                      | 4 ++--
 src/markdown/emit/inline-line.ts                          | 4 ++--
 src/markdown/emit/line-escaping.ts                        | 4 ++--
 src/markdown/emit/pipe-table.ts                           | 2 +-
 src/markdown/parse/inline-content.ts                      | 4 ++--
 src/markdown/parse/markdown-to-adf.ts                     | 8 ++++----
 src/markdown/parse/plain-markdown-to-adf.test.ts          | 2 +-
 .../adf-to-plain-markdown.test.ts}                        | 2 +-
 .../plain-reduction.ts => plain/adf-to-plain-markdown.ts} | 8 ++++----
 .../{plain-conventions.ts => plain/conventions.ts}        | 2 +-
 src/{adf => markdown/plain}/editor-normal.test.ts         | 4 ++--
 src/{adf => markdown/plain}/editor-normal.ts              | 6 +++---
 .../{emit/plain-inline.ts => plain/inline-reduction.ts}   | 6 +++---
 src/markdown/{parse => plain}/task-ids.test.ts            | 0
 src/markdown/{parse => plain}/task-ids.ts                 | 0
 todo.md                                                   | 2 +-
 20 files changed, 38 insertions(+), 35 deletions(-)
 rename src/markdown/{emit/plain-reduction.test.ts => plain/adf-to-plain-markdown.test.ts} (99%)
 rename src/markdown/{emit/plain-reduction.ts => plain/adf-to-plain-markdown.ts} (99%)
 rename src/markdown/{plain-conventions.ts => plain/conventions.ts} (97%)
 rename src/{adf => markdown/plain}/editor-normal.test.ts (97%)
 rename src/{adf => markdown/plain}/editor-normal.ts (95%)
 rename src/markdown/{emit/plain-inline.ts => plain/inline-reduction.ts} (98%)
 rename src/markdown/{parse => plain}/task-ids.test.ts (100%)
 rename src/markdown/{parse => plain}/task-ids.ts (100%)

diff --git a/docs/decisions.md b/docs/decisions.md
index b8f09d3..74cce04 100644
--- a/docs/decisions.md
+++ b/docs/decisions.md
@@ -642,8 +642,8 @@ is the markdown flavour's choice, not ADF's.
 
 ## The source parts by ADF and format
 
-2026-08-27, placement 2026-09-18, `adf/`'s bar 2026-09-21, the maintainer. Goal 2. Valid while
-each format has a reader and a writer through ADF.
+2026-08-27, placement 2026-09-18, `adf/`'s bar 2026-09-21, `plain/` 2026-10-03, the maintainer.
+Goal 2. Valid while each format has a reader and a writer through ADF.
 
 `src/adf/` holds ADF's own knowledge, imports no format, and is where a construct both formats read
 lives: the question is answered in ADF's vocabulary — a node type, an attribute kind, a content
@@ -666,3 +666,6 @@ conservative the copy would be. Where the rule is the emitter's own choice, inpu
 rather than restating it, and that is the only import `parse/` takes from `emit/` —
 `commonMarkSpelling` and `openingLinkTakesDirective` — so no fixture the emitter writes can be
 refused, and a spelling the emitter refuses gives its own error rather than a second name for it.
+`markdown/plain/` holds the plain flavour's own code — the writer's reduction to editor-normal ADF
+and the conventions and task ids the reader takes — so neither direction reaches into the other
+for it.
diff --git a/src/conformance/adf-property.test.ts b/src/conformance/adf-property.test.ts
index 4b787ac..96a8c83 100644
--- a/src/conformance/adf-property.test.ts
+++ b/src/conformance/adf-property.test.ts
@@ -5,10 +5,10 @@ import test from 'node:test'
 import type { AdfNode } from '../adf/document.ts'
 import { adfDocument, propertyRuns, propertyTimeout } from './property-harness.ts'
 import { adfToMarkdown } from '../markdown/emit/adf-to-markdown.ts'
-import { adfToPlainMarkdown, reduceToPlain } from '../markdown/emit/plain-reduction.ts'
+import { adfToPlainMarkdown, reduceToPlain } from '../markdown/plain/adf-to-plain-markdown.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'
+import { toEditorNormal } from '../markdown/plain/editor-normal.ts'
 
 const gateRuns = 1600
 const renamedPrefix = '!adg:'
diff --git a/src/conformance/property-harness.ts b/src/conformance/property-harness.ts
index 32ddcf5..0743e5a 100644
--- a/src/conformance/property-harness.ts
+++ b/src/conformance/property-harness.ts
@@ -11,7 +11,7 @@ import { blockNodes } from '../adf/block-nodes.ts'
 import { directivePrefix } from '../markdown/directive-syntax.ts'
 import { emptyKeys, mergeAdjacentText } from '../adf/document.ts'
 import { inlineNodes } from '../adf/inline-nodes.ts'
-import { joinsNormally } from '../adf/editor-normal.ts'
+import { joinsNormally } from '../markdown/plain/editor-normal.ts'
 import { markAttributes } from '../adf/mark-attributes.ts'
 
 type Positions = { block: AdfNode; inline: AdfNode }
diff --git a/src/index.ts b/src/index.ts
index a25f670..e4de874 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,6 +3,6 @@ export type { AdfAttributes, AdfDocument, AdfMark, AdfNode } from './adf/documen
 export type { ConvertError, ConvertErrorCode, ConvertErrorPath, ParseError, Result, SourcePosition } from './result.ts'
 export type { JsonValue } from './json-value.ts'
 export { adfToMarkdown } from './markdown/emit/adf-to-markdown.ts'
-export { adfToPlainMarkdown } from './markdown/emit/plain-reduction.ts'
+export { adfToPlainMarkdown } from './markdown/plain/adf-to-plain-markdown.ts'
 export { isAdfDocument } from './adf/document.ts'
 export { markdownToAdf, plainMarkdownToAdf } from './markdown/parse/markdown-to-adf.ts'
diff --git a/src/markdown/emit/adf-to-markdown.ts b/src/markdown/emit/adf-to-markdown.ts
index 867dfc8..99331ec 100644
--- a/src/markdown/emit/adf-to-markdown.ts
+++ b/src/markdown/emit/adf-to-markdown.ts
@@ -1,8 +1,8 @@
 import type { AdfDocument, AdfNode } from '../../adf/document.ts'
 import type { BlockNodeModel } from '../../adf/block-nodes.ts'
-import type { Flavour } from '../plain-conventions.ts'
+import type { Flavour } from '../plain/conventions.ts'
 import { adfDocumentFault, carriesOnly, isPlainText, nodeAttrs, nodeContent } from '../../adf/document.ts'
-import { alertMarker, foldedAlertMarker, leadingMarker, readAlertMarker, readTaskMarker, taskMarker } from '../plain-conventions.ts'
+import { alertMarker, foldedAlertMarker, leadingMarker, readAlertMarker, readTaskMarker, taskMarker } from '../plain/conventions.ts'
 import { blockDirectiveForm, documentSpelling, listBreakSpelling } from '../block-directive.ts'
 import { blockNodeModel, blockNodes } from '../../adf/block-nodes.ts'
 import { carriedBlock } from '../opaque-carry.ts'
diff --git a/src/markdown/emit/inline-line.ts b/src/markdown/emit/inline-line.ts
index 6be52b0..6513e8d 100644
--- a/src/markdown/emit/inline-line.ts
+++ b/src/markdown/emit/inline-line.ts
@@ -1,5 +1,5 @@
 import type { AdfMark, AdfNode } from '../../adf/document.ts'
-import type { Flavour } from '../plain-conventions.ts'
+import type { Flavour } from '../plain/conventions.ts'
 import type { InlineNodeModel } from '../../adf/inline-nodes.ts'
 import type { LineContainer } from '../line-container.ts'
 import { assembleInlineLine, isSyntax, type InlineEscaping, type InlineSegment, type MarkRun, type NodeRange } from './line-escaping.ts'
@@ -9,7 +9,7 @@ import { commonMarkLink, linkHref, markSpelling, spellMarkAttributes } from '../
 import { identicalMark, isPlainText, nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
 import { escapeUnbalanced, spellDestination } from '../commonmark/link-syntax.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
-import { highlightDelimiter } from '../plain-conventions.ts'
+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'
diff --git a/src/markdown/emit/line-escaping.ts b/src/markdown/emit/line-escaping.ts
index 253df18..120faf8 100644
--- a/src/markdown/emit/line-escaping.ts
+++ b/src/markdown/emit/line-escaping.ts
@@ -1,10 +1,10 @@
-import type { Flavour } from '../plain-conventions.ts'
+import type { Flavour } from '../plain/conventions.ts'
 import type { LineContainer } from '../line-container.ts'
 import { backslashEscape, escapesLineClaim, inlineHtmlConstruct, opensBracketedAutolink, opensEmailAutolink, type LinePosition } from '../commonmark/grammar.ts'
 import { backtickRun, closingBacktickRun } from '../commonmark/backtick-runs.ts'
 import { claimsDirectivePrefix } from '../directive-syntax.ts'
 import { delimiterFlags, isWordCharacter, matchEmphasis, runLength } from '../commonmark/emphasis-matching.ts'
-import { highlightDelimiter, highlightFlanking } from '../plain-conventions.ts'
+import { highlightDelimiter, highlightFlanking } from '../plain/conventions.ts'
 import { isBareDelimiterRow } from '../pipe-table-syntax.ts'
 import { opensLinkDefinition } from '../commonmark/link-reference-definitions.ts'
 import { readEntityReference } from '../commonmark/entity-references.ts'
diff --git a/src/markdown/emit/pipe-table.ts b/src/markdown/emit/pipe-table.ts
index f200e6d..89ab454 100644
--- a/src/markdown/emit/pipe-table.ts
+++ b/src/markdown/emit/pipe-table.ts
@@ -1,6 +1,6 @@
 import type { AdfNode } from '../../adf/document.ts'
 import type { ConvertErrorPath } from '../../result.ts'
-import type { Flavour } from '../plain-conventions.ts'
+import type { Flavour } from '../plain/conventions.ts'
 import { carriesOnly, nodeContent } from '../../adf/document.ts'
 import { spellPipeDelimiter, spellPipeRow } from '../pipe-table-syntax.ts'
 import { tryPipeCell } from './inline-line.ts'
diff --git a/src/markdown/parse/inline-content.ts b/src/markdown/parse/inline-content.ts
index b2bfd69..22d7114 100644
--- a/src/markdown/parse/inline-content.ts
+++ b/src/markdown/parse/inline-content.ts
@@ -1,7 +1,7 @@
 import type { AdfMark, AdfNode } from '../../adf/document.ts'
 import type { DirectiveSpan, NestedSpans } from '../directive-syntax.ts'
 import type { EmphasisPairing } from '../commonmark/emphasis-matching.ts'
-import type { Flavour } from '../plain-conventions.ts'
+import type { Flavour } from '../plain/conventions.ts'
 import type { LineContainer } from '../line-container.ts'
 import type { LinkDefinition } from '../commonmark/link-syntax.ts'
 import { backslashEscape, decodeTextEscapes, inlineHtmlConstruct, readBracketedAutolink, readEmailAutolink, trimTrailingSpace } from '../commonmark/grammar.ts'
@@ -9,7 +9,7 @@ import { backtickRun, closingBacktickRun } from '../commonmark/backtick-runs.ts'
 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 { highlightDelimiter, highlightFlanking } from '../plain/conventions.ts'
 import { identicalMarks, mergeAdjacentText, nodeAttrs, nodeMarks } from '../../adf/document.ts'
 import { inlineNodeModel } from '../../adf/inline-nodes.ts'
 import { noSpans, readInlineDirective } from '../directive-syntax.ts'
diff --git a/src/markdown/parse/markdown-to-adf.ts b/src/markdown/parse/markdown-to-adf.ts
index 1df55ff..26907f8 100644
--- a/src/markdown/parse/markdown-to-adf.ts
+++ b/src/markdown/parse/markdown-to-adf.ts
@@ -2,7 +2,7 @@ import type { AdfDocument, AdfNode } from '../../adf/document.ts'
 import type { Block, DirectiveBlock } from './blocks.ts'
 import type { BlockDirectiveNode } from './directive-nodes.ts'
 import type { ConvertFault } from '../../result.ts'
-import type { Flavour } from '../plain-conventions.ts'
+import type { Flavour } from '../plain/conventions.ts'
 import type { LineContainer } from '../line-container.ts'
 import type { LinkDefinitions } from './inline-content.ts'
 import { carryFenceType, readCarriedBlock } from '../opaque-carry.ts'
@@ -10,11 +10,11 @@ import { commonMarkSpelling, type SpellingMemo } from '../emit/adf-to-markdown.t
 import { documentAttribute, documentName, documentSpelling, listBreakName, listBreakSpelling } from '../block-directive.ts'
 import { emptyKeys, nodeAttrs, nodeContent } from '../../adf/document.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 { inlineLeaves } from '../plain/inline-reduction.ts'
 import { languageSlot } from '../code-language.ts'
 import { largestNesting } from '../../nesting.ts'
-import { leadingMarker, readAlertMarker, readTaskMarker } from '../plain-conventions.ts'
-import { mintTaskIds } from './task-ids.ts'
+import { leadingMarker, readAlertMarker, readTaskMarker } from '../plain/conventions.ts'
+import { mintTaskIds } from '../plain/task-ids.ts'
 import { parseBlocks } from './blocks.ts'
 import { parseInlineContent } from './inline-content.ts'
 import { readBlockDirectiveNode } from './directive-nodes.ts'
diff --git a/src/markdown/parse/plain-markdown-to-adf.test.ts b/src/markdown/parse/plain-markdown-to-adf.test.ts
index ae1f96d..af6aee2 100644
--- a/src/markdown/parse/plain-markdown-to-adf.test.ts
+++ b/src/markdown/parse/plain-markdown-to-adf.test.ts
@@ -3,7 +3,7 @@ import test from 'node:test'
 
 import type { AdfAttributes, AdfDocument, AdfMark, AdfNode } from '../../adf/document.ts'
 import { adfToMarkdown } from '../emit/adf-to-markdown.ts'
-import { adfToPlainMarkdown } from '../emit/plain-reduction.ts'
+import { adfToPlainMarkdown } from '../plain/adf-to-plain-markdown.ts'
 import { largestNesting } from '../../nesting.ts'
 import { markdownToAdf, plainMarkdownToAdf } from './markdown-to-adf.ts'
 
diff --git a/src/markdown/emit/plain-reduction.test.ts b/src/markdown/plain/adf-to-plain-markdown.test.ts
similarity index 99%
rename from src/markdown/emit/plain-reduction.test.ts
rename to src/markdown/plain/adf-to-plain-markdown.test.ts
index 185ae42..28db1b7 100644
--- a/src/markdown/emit/plain-reduction.test.ts
+++ b/src/markdown/plain/adf-to-plain-markdown.test.ts
@@ -2,7 +2,7 @@ import assert from 'node:assert/strict'
 import test from 'node:test'
 
 import type { AdfAttributes, AdfDocument, AdfMark, AdfNode } from '../../adf/document.ts'
-import { adfToPlainMarkdown, reduceToPlain } from './plain-reduction.ts'
+import { adfToPlainMarkdown, reduceToPlain } from './adf-to-plain-markdown.ts'
 import { largestNesting } from '../../nesting.ts'
 
 const code: AdfMark = { type: 'code' }
diff --git a/src/markdown/emit/plain-reduction.ts b/src/markdown/plain/adf-to-plain-markdown.ts
similarity index 99%
rename from src/markdown/emit/plain-reduction.ts
rename to src/markdown/plain/adf-to-plain-markdown.ts
index 2545002..f324ba3 100644
--- a/src/markdown/emit/plain-reduction.ts
+++ b/src/markdown/plain/adf-to-plain-markdown.ts
@@ -1,14 +1,14 @@
 import type { AdfDocument, AdfNode } from '../../adf/document.ts'
 import { adfDocumentFault, nodeAttrs, nodeContent } from '../../adf/document.ts'
-import { commonMarkSpelling, largestListMarker, writeMarkdown, type SpellingMemo } from './adf-to-markdown.ts'
+import { commonMarkSpelling, largestListMarker, writeMarkdown, type SpellingMemo } from '../emit/adf-to-markdown.ts'
 import { blockNodeModel } from '../../adf/block-nodes.ts'
 import { failure, faulted, success, type ConvertErrorPath, type Result } from '../../result.ts'
-import { inlineLeaves, isBlockNodeType, oneLine, reduceInline, writableHref } from './plain-inline.ts'
+import { inlineLeaves, isBlockNodeType, oneLine, reduceInline, writableHref } from './inline-reduction.ts'
 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'
+import { taskMarker } from './conventions.ts'
+import { toEditorNormal } from './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 }
diff --git a/src/markdown/plain-conventions.ts b/src/markdown/plain/conventions.ts
similarity index 97%
rename from src/markdown/plain-conventions.ts
rename to src/markdown/plain/conventions.ts
index c5d6f09..be6c5c7 100644
--- a/src/markdown/plain-conventions.ts
+++ b/src/markdown/plain/conventions.ts
@@ -1,4 +1,4 @@
-import { isWordCharacter } from './commonmark/emphasis-matching.ts'
+import { isWordCharacter } from '../commonmark/emphasis-matching.ts'
 
 export type Flavour = 'lossless' | 'plain'
 
diff --git a/src/adf/editor-normal.test.ts b/src/markdown/plain/editor-normal.test.ts
similarity index 97%
rename from src/adf/editor-normal.test.ts
rename to src/markdown/plain/editor-normal.test.ts
index bb0dd40..33d538a 100644
--- a/src/adf/editor-normal.test.ts
+++ b/src/markdown/plain/editor-normal.test.ts
@@ -1,8 +1,8 @@
 import assert from 'node:assert/strict'
 import test from 'node:test'
 
-import type { AdfNode } from './document.ts'
-import type { JsonValue } from '../json-value.ts'
+import type { AdfNode } from '../../adf/document.ts'
+import type { JsonValue } from '../../json-value.ts'
 import { toEditorNormal } from './editor-normal.ts'
 
 test('merges adjacent text nodes carrying identical marks, at every level', () => {
diff --git a/src/adf/editor-normal.ts b/src/markdown/plain/editor-normal.ts
similarity index 95%
rename from src/adf/editor-normal.ts
rename to src/markdown/plain/editor-normal.ts
index a89c0df..a5ffb7e 100644
--- a/src/adf/editor-normal.ts
+++ b/src/markdown/plain/editor-normal.ts
@@ -1,6 +1,6 @@
-import type { AdfAttributes, AdfDocument, AdfMark, AdfNode } from './document.ts'
-import type { JsonValue } from '../json-value.ts'
-import { identicalMark, identicalMarks, mergeAdjacentText, nodeAttrs, nodeContent, nodeMarks } from './document.ts'
+import type { AdfAttributes, AdfDocument, AdfMark, AdfNode } from '../../adf/document.ts'
+import type { JsonValue } from '../../json-value.ts'
+import { identicalMark, identicalMarks, mergeAdjacentText, nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
 
 type JsonContainer = JsonValue[] | { [key: string]: JsonValue }
 
diff --git a/src/markdown/emit/plain-inline.ts b/src/markdown/plain/inline-reduction.ts
similarity index 98%
rename from src/markdown/emit/plain-inline.ts
rename to src/markdown/plain/inline-reduction.ts
index f8e89b5..b2d3501 100644
--- a/src/markdown/emit/plain-inline.ts
+++ b/src/markdown/plain/inline-reduction.ts
@@ -1,12 +1,12 @@
 import type { AdfAttributes, AdfMark, AdfNode } from '../../adf/document.ts'
 import type { LineContainer } from '../line-container.ts'
-import type { MarkRun } from './line-escaping.ts'
+import type { MarkRun } from '../emit/line-escaping.ts'
 import { blockNodeModel } from '../../adf/block-nodes.ts'
 import { failure, success, type ConvertErrorPath, type Result } from '../../result.ts'
-import { joinsNormally, sameMark } from '../../adf/editor-normal.ts'
+import { joinsNormally, sameMark } from './editor-normal.ts'
 import { largestNesting } from '../../nesting.ts'
 import { mergeAdjacentText, nodeAttrs, nodeContent, nodeMarks } from '../../adf/document.ts'
-import { plainLineFallback, type PlainLineFallback } from './inline-line.ts'
+import { plainLineFallback, type PlainLineFallback } from '../emit/inline-line.ts'
 import { spellDestination, spellLinkTarget } from '../commonmark/link-syntax.ts'
 
 const highlight = 'backgroundColor'
diff --git a/src/markdown/parse/task-ids.test.ts b/src/markdown/plain/task-ids.test.ts
similarity index 100%
rename from src/markdown/parse/task-ids.test.ts
rename to src/markdown/plain/task-ids.test.ts
diff --git a/src/markdown/parse/task-ids.ts b/src/markdown/plain/task-ids.ts
similarity index 100%
rename from src/markdown/parse/task-ids.ts
rename to src/markdown/plain/task-ids.ts
diff --git a/todo.md b/todo.md
index 4e44c5e..f775b28 100644
--- a/todo.md
+++ b/todo.md
@@ -154,7 +154,7 @@ punctuation — and, where they do, read the code point, with a fixture per dire
 
 ### 42. Trim a text leaf's trailing blanks in linear time.
 
-`plain-inline.ts`'s `leafEdges` finds the trail with an unanchored `/[ \t]*$/`, quadratic in a run
+`plain/inline-reduction.ts`'s `leafEdges` finds the trail with an unanchored `/[ \t]*$/`, quadratic in a run
 of blanks inside one leaf: a paragraph of `a`, 80 000 spaces, `b` takes 6.5 s in
 `adfToPlainMarkdown`. Scan backward, as the expand title's trim does.