plan(HTML‑to‑Markdown): add sample code

.opencode/plans/1775291477517-lucky-garden.md

@@ -44,23 +44,12 @@ const DEFAULT_CONFIG: FormatConfig = {
 };
 ```
 
-## Transformation Order (leaf-to-parent)
+## Transformation Order
 
-1. **Inline leaves** (processed first, no children affected):
+0. **`addNewlinesAfterBlocks($)`** — global newline injection (existing function, runs first)
-   - `emu-xref a[href]` → `<span class="link-markdown">[text](#hash)</span>`. Target the inner `<a>` tag (always has href, unlike `emu-xref` which may lack it).
+1. **Inline leaves**: `emu-xref a[href]` → links, `var`/`emu-val`/`emu-const` → inline code
-     - Strip filename prefix from href (e.g., `abstract-operations.html#sec-tonumber` → `#sec-tonumber`)
+2. **Block leaves**: `pre>code` → fenced code, `emu-eqn` → fenced code
-     - Discard `e-user-code` class.
+3. **Structural parents**: `emu-grammar` → fenced bnf (uses `.text()` with pre-injected newlines), `ol/ul` → markdown lists, `table` → markdown tables
-     - Replace `<a>` inside `emu-xref` (leaving wrapper `emu-xref` to be ignored by text splitter)
-   - `var`, `emu-val`, `emu-const`, `code`, inline `emu-eqn` → `<span class="inline-code">`text`</span>`. Strip inner elements, plain text only.
-2. **Block leaves**:
-   - `pre>code` → `<pre class="code-markdown">```language\ntext\n```</pre>`. Language from `class` attribute. Strip hljs spans. Plain text.
-   - block `emu-eqn` → `<pre class="code-markdown">```\ntext\n```</pre>`. No language tag. Strip inner elements.
-3. **Structural parents** (children already resolved):
-   - `emu-grammar` → `<pre class="code-markdown">```bnf\ntext\n```</pre>`. Extract text from grammar inner tags (emu-nt, emu-t, etc.).
-   - `ol` → `<pre class="list-markdown">1. item\n   1. nested</pre>`. Nested via 2-space indentation.
-   - `ul` → `<pre class="list-markdown">- item\n  - nested</pre>`. Nested via 2-space indentation.
-   - `table`, `emu-table` → `<pre class="table-markdown">...existing markdown...</pre>`. Existing `convertTablesToMarkdown` works unchanged — `.text()` already extracts markdown text from pre-processed spans.
-4. **`addNewlinesAfterBlocks($)`** (existing, unchanged — operates on remaining DOM elements)
 
 ## Implementation Details
 
@@ -95,6 +84,216 @@ Each function receives `cheerio.CheerioAPI` and modifies the DOM in-place.
 
 6. **`formatForIngestion($, config?)`** — orchestrator, calls all in order
 
+## Critical Implementation Code
+
+### Config interface
+
+```typescript
+export interface FormatConfig {
+  codeBlocks: {
+    block: string[];
+    inline: string[];
+    grammar: string[];
+  };
+  links: string[];
+  lists: {
+    ordered: string[];
+    unordered: string[];
+  };
+  tables: string[];
+}
+
+export const DEFAULT_CONFIG: FormatConfig = {
+  codeBlocks: {
+    block: ["pre>code", "emu-eqn:not([class*='inline'])"],
+    inline: ["var", "emu-val", "emu-const", "emu-eqn.inline"],
+    grammar: ["emu-grammar"],
+  },
+  links: ["emu-xref a"],
+  lists: {
+    ordered: ["ol"],
+    unordered: ["ul"],
+  },
+  tables: ["table", "emu-table"],
+};
+```
+
+### `convertLinksToMarkdown` — filename stripping
+
+```typescript
+export function convertLinksToMarkdown(
+  $: cheerio.CheerioAPI,
+  selector: string = "emu-xref a[href]",
+): void {
+  $(selector).each((_, elem) => {
+    const $a = $(elem);
+    const href = $a.attr("href") ?? "";
+
+    // Skip external links
+    if (href.startsWith("http")) return;
+
+    // Strip filename prefix: "abstract-operations.html#sec-tonumber" → "#sec-tonumber"
+    const hash = href.includes("#") ? `#${href.split("#")[1]}` : href;
+    const text = $a.text().trim();
+
+    if (!text || !hash) return;
+
+    $a.replaceWith(`<span class="link-markdown">[${text}](${hash})</span>`);
+  });
+}
+```
+
+### `convertInlineCodeToMarkdown` — backtick wrapping
+
+```typescript
+export function convertInlineCodeToMarkdown(
+  $: cheerio.CheerioAPI,
+  tags: string[],
+): void {
+  for (const tag of tags) {
+    $(tag).each((_, elem) => {
+      // Skip <code> inside <pre> (handled by block converter)
+      if (elem.name === "code" && $(elem).parent("pre").length > 0) return;
+
+      const text = $(elem).text().trim();
+      if (!text) return;
+      $(elem).replaceWith(`<span class="inline-code">\`${text}\`</span>`);
+    });
+  }
+}
+```
+
+### `convertBlockCodeToMarkdown` — fenced code blocks
+
+```typescript
+function extractLanguage(codeClass: string | undefined): string {
+  // "javascript hljs" → "javascript", "python hljs" → "python"
+  if (!codeClass) return "";
+  const match = codeClass.match(/^(\w+)/);
+  return match?.[1] ?? "";
+}
+
+export function convertBlockCodeToMarkdown(
+  $: cheerio.CheerioAPI,
+  tags: string[],
+): void {
+  // Handle pre>code (JS code examples)
+  $("pre > code").each((_, code) => {
+    const lang = extractLanguage($(code).attr("class"));
+    const text = $(code).text().trim();
+    const pre = $(code).parent("pre");
+    pre.replaceWith(
+      $(`<pre class="code-markdown">\`\`\`${lang}\n${text}\n\`\`\`</pre>`),
+    );
+  });
+
+  // Handle standalone emu-eqn (block-level equations)
+  $("emu-eqn:not([class*='inline'])").each((_, eqn) => {
+    const text = $(eqn).text().trim();
+    $(eqn).replaceWith(
+      $(`<pre class="code-markdown">\`\`\`\n${text}\n\`\`\`</pre>`),
+    );
+  });
+}
+```
+
+### `convertListsToMarkdown` — recursive list processing
+
+```typescript
+function listToMarkdown(
+  $: cheerio.CheerioAPI,
+  elem: cheerio.Element,
+  depth: number = 0,
+): string {
+  const $elem = $(elem);
+  const isOrdered = elem.name === "ol";
+  const indent = "  ".repeat(depth);
+  const lines: string[] = [];
+
+  $elem.children("li").each((i, li) => {
+    const prefix = isOrdered ? `${i + 1}. ` : "- ";
+    const $li = $(li);
+
+    // Recurse into nested lists first (depth-first)
+    $li.children("ol, ul").each((_, nested) => {
+      const nestedMarkdown = listToMarkdown($, nested, depth + 1);
+      $(nested).replaceWith($(`<pre class="list-processed">${nestedMarkdown}</pre>`));
+    });
+
+    // Now get full text (nested lists are replaced with <pre> containing markdown)
+    const itemText = $li.text().trim().replace(/\s+/g, " ");
+    lines.push(`${indent}${prefix}${itemText}`);
+  });
+
+  return lines.join("\n");
+}
+
+export function convertListsToMarkdown(
+  $: cheerio.CheerioAPI,
+  ordered: string[] = ["ol"],
+  unordered: string[] = ["ul"],
+): void {
+  const selectors = [...ordered, ...unordered].join(", ");
+  // Process from outermost — recursion handles depth-first nesting
+  $(selectors).each((_, elem) => {
+    // Skip if already processed (parent already handled this)
+    if ($(elem).hasClass("list-markdown")) return;
+    const markdown = listToMarkdown($, elem, 0);
+    $(elem).replaceWith($(`<pre class="list-markdown">${markdown}</pre>`));
+  });
+}
+```
+
+Key insight: recursion goes depth-first. When processing an `li`, nested `ol`/`ul` children are first replaced with `<pre class="list-processed">` containing their markdown. Then `$li.text()` includes that markdown. Outer `$(selectors).each(...)` skips already-processed elements.
+
+### `convertGrammarToMarkdown` — grammar production text
+
+`addNewlinesAfterBlocks` runs first globally, injecting `\n` after `emu-production` and `emu-rhs` (added to `BLOCK_ELEMENTS`). Then `.text()` on `emu-grammar` naturally preserves production/alternative boundaries.
+
+```typescript
+export function convertGrammarToMarkdown(
+  $: cheerio.CheerioAPI,
+  selector: string = "emu-grammar",
+): void {
+  $(selector).each((_, grammar) => {
+    const text = $(grammar).text().trim();
+    $(grammar).replaceWith(
+      $(`<pre class="code-markdown">\`\`\`bnf\n${text}\n\`\`\`</pre>`),
+    );
+  });
+}
+```
+
+Add `"emu-production"` and `"emu-rhs"` to `BLOCK_ELEMENTS` array.
+
+### `formatForIngestion` — orchestrator
+
+```typescript
+export function formatForIngestion(
+  $: cheerio.CheerioAPI,
+  config: Partial<FormatConfig> = {},
+): void {
+  const cfg = { ...DEFAULT_CONFIG, ...config };
+
+  // 1. Inject newlines globally (affects li, p, pre, emu-production, emu-rhs, etc.)
+  addNewlinesAfterBlocks($);
+
+  // 2. Inline leaves (links first — must be before lists/code destroy DOM)
+  convertLinksToMarkdown($, cfg.links.join(", "));
+
+  // 3. Inline code
+  convertInlineCodeToMarkdown($, cfg.codeBlocks.inline);
+
+  // 4. Block leaves (fenced code)
+  convertBlockCodeToMarkdown($, cfg.codeBlocks.block);
+
+  // 5. Structural parents (grammar, lists, tables)
+  convertGrammarToMarkdown($, cfg.codeBlocks.grammar.join(", "));
+  convertListsToMarkdown($, cfg.lists.ordered, cfg.lists.unordered);
+  convertTablesToMarkdown($);
+}
+```
+
 ### Modify existing functions
 
 - **`convertTablesToMarkdown($)`**: No changes needed. `.text()` already extracts markdown text from pre-processed `<span>` elements.