Add TOC support

Co-authored-by: Copilot <copilot@github.com>

lib/Md/MdParser.cpp

@@ -17,6 +17,17 @@ static std::string trimLeft(const std::string& s) {
   return s.substr(i);
 }
 
+static bool isWordChar(char c) { return std::isalnum(static_cast<unsigned char>(c)) || c == '_'; }
+
+static bool isUnderscoreEmphasis(const std::string& text, size_t pos, size_t count) {
+  if (pos == 0 || pos + count >= text.size()) {
+    return true;
+  }
+  const char before = text[pos - 1];
+  const char after = text[pos + count];
+  return !(isWordChar(before) && isWordChar(after));
+}
+
 static bool isHorizontalRuleLine(const std::string& line) {
   // Must be at least 3 chars of the same marker (-, *, _) with optional spaces
   if (line.size() < 3) return false;
@@ -65,6 +76,11 @@ std::vector<Span> parseInline(const std::string& text) {
 
     // *** or ___ — toggle both bold and italic
     if ((c == '*' || c == '_') && i + 2 < text.size() && text[i + 1] == c && text[i + 2] == c) {
+      if (c == '_' && !isUnderscoreEmphasis(text, i, 3)) {
+        current.append(3, c);
+        i += 3;
+        continue;
+      }
       emitSpan();
       bold = !bold;
       italic = !italic;
@@ -74,6 +90,11 @@ std::vector<Span> parseInline(const std::string& text) {
 
     // ** or __ — toggle bold
     if ((c == '*' || c == '_') && i + 1 < text.size() && text[i + 1] == c) {
+      if (c == '_' && !isUnderscoreEmphasis(text, i, 2)) {
+        current.append(2, c);
+        i += 2;
+        continue;
+      }
       emitSpan();
       bold = !bold;
       i += 2;
@@ -82,6 +103,11 @@ std::vector<Span> parseInline(const std::string& text) {
 
     // * or _ — toggle italic
     if (c == '*' || c == '_') {
+      if (c == '_' && !isUnderscoreEmphasis(text, i, 1)) {
+        current.push_back(c);
+        i += 1;
+        continue;
+      }
       emitSpan();
       italic = !italic;
       i += 1;

src/activities/reader/MDReaderActivity.h

@@ -8,6 +8,13 @@
 #include "CrossPointSettings.h"
 #include "activities/Activity.h"
 
+struct MdHeading {
+  size_t offset = 0;
+  int level = 1;
+  std::string title;
+  int pageIndex = -1;
+};
+
 class MdReaderActivity final : public Activity {
   std::unique_ptr<Txt> txt;
 
@@ -26,6 +33,11 @@ class MdReaderActivity final : public Activity {
   std::vector<size_t> pageOffsets;
   std::vector<uint8_t> pageCodeBlockState;  // 1 if page starts inside a code block
   std::vector<RenderedLine> currentPageLines;
+  std::vector<uint8_t> pageBuffer;
+
+  std::vector<MdHeading> headings;
+  int currentHeadingIndex = -1;
+
   int linesPerPage = 0;
   int viewportWidth = 0;
   bool initialized = false;
@@ -55,6 +67,13 @@ class MdReaderActivity final : public Activity {
   void savePageIndexCache() const;
   void saveProgress() const;
   void loadProgress();
+  void scanHeadings();
+  void assignHeadingPageNumbers();
+  int getHeadingIndexForOffset(size_t offset) const;
+  void jumpToHeading(bool next);
+  void scanHeadings();
+  int getHeadingIndexForOffset(size_t offset) const;
+  void jumpToHeading(bool next);
 
   // Word-wrap a parsed markdown line into one or more RenderedLines.
   // Returns true if all content was emitted, false if truncated by maxLines.

src/activities/reader/MdReaderActivity.cpp

@@ -7,11 +7,13 @@
 #include <Serialization.h>
 #include <Utf8.h>
 
+#include <algorithm>
 #include <numeric>
 
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
 #include "MappedInputManager.h"
+#include "MdReaderTocSelectionActivity.h"
 #include "ReaderUtils.h"
 #include "RecentBooksStore.h"
 #include "components/UITheme.h"
@@ -19,8 +21,18 @@
 
 namespace {
 constexpr size_t CHUNK_SIZE = 8 * 1024;
+constexpr size_t MAX_LINE_LENGTH = 64 * 1024;
+constexpr unsigned long HEADING_SKIP_MS = 700;
 constexpr uint32_t CACHE_MAGIC = 0x4D4B4449;  // "MKDI"
 constexpr uint8_t CACHE_VERSION = 3;          // Bumped: nested list indent + task checkboxes
+
+static std::string flattenHeadingText(const MdParser::ParsedLine& parsed) {
+  std::string result;
+  for (const auto& span : parsed.spans) {
+    result += span.text;
+  }
+  return result;
+}
 }  // namespace
 
 void MdReaderActivity::onEnter() {
@@ -38,11 +50,163 @@ void MdReaderActivity::onEnter() {
   auto fileName = filePath.substr(filePath.rfind('/') + 1);
   APP_STATE.openEpubPath = filePath;
   APP_STATE.saveToFile();
-  RECENT_BOOKS.addBook(filePath, fileName, "", "");
+  RECENT_BOOKS.addBook(filePath, fileName, "", "", "");
 
   requestUpdate();
 }
 
+void MdReaderActivity::assignHeadingPageNumbers() {
+  if (pageOffsets.empty()) {
+    return;
+  }
+  for (auto& heading : headings) {
+    const auto it = std::upper_bound(pageOffsets.begin(), pageOffsets.end(), heading.offset);
+    heading.pageIndex = static_cast<int>((it == pageOffsets.begin()) ? 0 : (it - pageOffsets.begin() - 1));
+  }
+}
+
+int MdReaderActivity::getHeadingIndexForOffset(size_t offset) const {
+  if (headings.empty()) {
+    return -1;
+  }
+  int index = -1;
+  for (int i = 0; i < static_cast<int>(headings.size()); i++) {
+    if (headings[i].offset <= offset) {
+      index = i;
+    } else {
+      break;
+    }
+  }
+  return index;
+}
+
+void MdReaderActivity::jumpToHeading(bool next) {
+  if (headings.empty() || pageOffsets.empty()) {
+    return;
+  }
+
+  const size_t currentOffset = (currentPage >= 0 && currentPage < totalPages) ? pageOffsets[currentPage] : 0;
+  int headingIndex = getHeadingIndexForOffset(currentOffset);
+
+  if (headingIndex < 0) {
+    headingIndex = next ? 0 : static_cast<int>(headings.size()) - 1;
+  } else {
+    headingIndex += next ? 1 : -1;
+  }
+
+  if (headingIndex < 0) {
+    headingIndex = 0;
+  } else if (headingIndex >= static_cast<int>(headings.size())) {
+    headingIndex = static_cast<int>(headings.size()) - 1;
+  }
+
+  const size_t headingOffset = headings[headingIndex].offset;
+  const auto it = std::upper_bound(pageOffsets.begin(), pageOffsets.end(), headingOffset);
+  if (it == pageOffsets.begin()) {
+    currentPage = 0;
+  } else {
+    currentPage = static_cast<int>(it - pageOffsets.begin() - 1);
+  }
+  currentHeadingIndex = headingIndex;
+  requestUpdate();
+}
+
+void MdReaderActivity::scanHeadings() {
+  headings.clear();
+  if (!txt) {
+    return;
+  }
+
+  const size_t fileSize = txt->getFileSize();
+  if (fileSize == 0) {
+    return;
+  }
+
+  std::string pending;
+  size_t pendingOffset = 0;
+  bool hasPending = false;
+  bool inCodeBlock = false;
+
+  pageBuffer.resize(CHUNK_SIZE + 1);
+  size_t offset = 0;
+
+  while (offset < fileSize) {
+    const size_t toRead = std::min(CHUNK_SIZE, fileSize - offset);
+    if (!txt->readContent(pageBuffer.data(), offset, toRead)) {
+      return;
+    }
+    pageBuffer[toRead] = '\0';
+
+    size_t pos = 0;
+    while (pos < toRead) {
+      size_t lineEnd = pos;
+      while (lineEnd < toRead && pageBuffer[lineEnd] != '\n') {
+        lineEnd++;
+      }
+
+      const bool hasNewline = (lineEnd < toRead && pageBuffer[lineEnd] == '\n');
+      const bool fileHasMore = (offset + toRead < fileSize);
+      const size_t rawLen = lineEnd - pos;
+      const bool hasCR = (rawLen > 0 && pageBuffer[pos + rawLen - 1] == '\r');
+      const size_t displayLen = hasCR ? rawLen - 1 : rawLen;
+      const size_t lineStartOffset = hasPending ? pendingOffset : (offset + pos);
+
+      std::string rawLine;
+      if (hasPending) {
+        rawLine = std::move(pending);
+        pending.clear();
+        hasPending = false;
+      }
+      rawLine.append(reinterpret_cast<char*>(pageBuffer.data() + pos), displayLen);
+
+      if (!hasNewline && fileHasMore) {
+        if (!hasPending) {
+          pendingOffset = lineStartOffset;
+        }
+        pending = std::move(rawLine);
+        hasPending = true;
+        break;
+      }
+
+      if (MdParser::isCodeFence(rawLine)) {
+        inCodeBlock = !inCodeBlock;
+      }
+      const MdParser::ParsedLine parsed = MdParser::parseLine(rawLine, inCodeBlock);
+      if (parsed.blockType == MdParser::BlockType::Header1 || parsed.blockType == MdParser::BlockType::Header2 ||
+          parsed.blockType == MdParser::BlockType::Header3) {
+        int level = 1;
+        if (parsed.blockType == MdParser::BlockType::Header2) {
+          level = 2;
+        } else if (parsed.blockType == MdParser::BlockType::Header3) {
+          level = 3;
+        }
+        headings.push_back({lineStartOffset, level, flattenHeadingText(parsed)});
+      }
+
+      pos = hasNewline ? lineEnd + 1 : lineEnd;
+    }
+
+    offset += toRead;
+  }
+
+  if (hasPending) {
+    if (MdParser::isCodeFence(pending)) {
+      inCodeBlock = !inCodeBlock;
+    }
+    const MdParser::ParsedLine parsed = MdParser::parseLine(pending, inCodeBlock);
+    if (parsed.blockType == MdParser::BlockType::Header1 || parsed.blockType == MdParser::BlockType::Header2 ||
+        parsed.blockType == MdParser::BlockType::Header3) {
+      int level = 1;
+      if (parsed.blockType == MdParser::BlockType::Header2) {
+        level = 2;
+      } else if (parsed.blockType == MdParser::BlockType::Header3) {
+        level = 3;
+      }
+      headings.push_back({pendingOffset, level, flattenHeadingText(parsed)});
+    }
+  }
+}
+
 void MdReaderActivity::onExit() {
   Activity::onExit();
 
@@ -68,17 +232,40 @@ void MdReaderActivity::loop() {
     return;
   }
 
+  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm) && !headings.empty()) {
+    currentHeadingIndex = getHeadingIndexForOffset(pageOffsets[currentPage]);
+    ReaderUtils::enforceExitFullRefresh(renderer);
+    startActivityForResult(
+        std::make_unique<MdReaderTocSelectionActivity>(renderer, mappedInput, headings, currentHeadingIndex),
+        [this](const ActivityResult& result) {
+          if (!result.isCancelled) {
+            currentPage = std::get<PageResult>(result.data).page;
+            currentHeadingIndex = getHeadingIndexForOffset(pageOffsets[currentPage]);
+            requestUpdate();
+          }
+        });
+    return;
+  }
+
   auto [prevTriggered, nextTriggered] = ReaderUtils::detectPageTurn(mappedInput);
   if (!prevTriggered && !nextTriggered) {
     return;
   }
 
+  const bool headingSkip = SETTINGS.longPressChapterSkip && mappedInput.getHeldTime() > HEADING_SKIP_MS;
+  if (headingSkip && !headings.empty()) {
+    jumpToHeading(nextTriggered);
+    return;
+  }
+
   if (prevTriggered && currentPage > 0) {
     currentPage--;
+    currentHeadingIndex = getHeadingIndexForOffset(pageOffsets[currentPage]);
     requestUpdate();
   } else if (nextTriggered) {
     if (currentPage < totalPages - 1) {
       currentPage++;
+      currentHeadingIndex = getHeadingIndexForOffset(pageOffsets[currentPage]);
       requestUpdate();
     } else {
       onGoHome();
@@ -107,6 +294,9 @@ void MdReaderActivity::initializeReader() {
   const int viewportHeight = renderer.getScreenHeight() - cachedOrientedMarginTop - cachedOrientedMarginBottom;
   const int lineHeight = renderer.getLineHeight(cachedFontId);
 
+  pageBuffer.reserve(CHUNK_SIZE + 1);
+  scanHeadings();
+
   linesPerPage = viewportHeight / lineHeight;
   if (linesPerPage < 1) linesPerPage = 1;
 
@@ -116,6 +306,7 @@ void MdReaderActivity::initializeReader() {
     buildPageIndex();
     savePageIndexCache();
   }
+  assignHeadingPageNumbers();
 
   loadProgress();
 
@@ -259,42 +450,57 @@ bool MdReaderActivity::loadPageAtOffset(size_t offset, bool startInCodeBlock, st
     return false;
   }
 
-  size_t chunkSize = std::min(CHUNK_SIZE, fileSize - offset);
-  auto* buffer = static_cast<uint8_t*>(malloc(chunkSize + 1));
-  if (!buffer) {
-    LOG_ERR("MDR", "Failed to allocate %zu bytes", chunkSize);
+  size_t bufferSize = std::min(CHUNK_SIZE, fileSize - offset);
+  pageBuffer.resize(bufferSize + 1);
+  if (!txt->readContent(pageBuffer.data(), offset, bufferSize)) {
     return false;
   }
-
-  if (!txt->readContent(buffer, offset, chunkSize)) {
-    free(buffer);
-    return false;
-  }
-  buffer[chunkSize] = '\0';
+  pageBuffer[bufferSize] = '\0';
 
   bool inCodeBlock = startInCodeBlock;
   size_t pos = 0;
 
-  while (pos < chunkSize && static_cast<int>(outLines.size()) < linesPerPage) {
-    // Find end of line
+  while (pos < bufferSize && static_cast<int>(outLines.size()) < linesPerPage) {
+    // Find end of line and extend the read buffer if we are at chunk boundary.
     size_t lineEnd = pos;
-    while (lineEnd < chunkSize && buffer[lineEnd] != '\n') {
+    while (lineEnd < bufferSize && pageBuffer[lineEnd] != '\n') {
       lineEnd++;
     }
 
-    // Check if we have a complete line
-    bool lineComplete = (lineEnd < chunkSize) || (offset + lineEnd >= fileSize);
+    while (lineEnd == bufferSize && offset + bufferSize < fileSize && bufferSize < MAX_LINE_LENGTH) {
+      size_t extra = std::min(CHUNK_SIZE, fileSize - offset - bufferSize);
+      if (bufferSize + extra > MAX_LINE_LENGTH) {
+        extra = MAX_LINE_LENGTH - bufferSize;
+      }
+      if (extra == 0) {
+        break;
+      }
 
+      pageBuffer.resize(bufferSize + extra + 1);
+      if (!txt->readContent(pageBuffer.data() + bufferSize, offset + bufferSize, extra)) {
+        return false;
+      }
+      bufferSize += extra;
+      pageBuffer[bufferSize] = '\0';
+
+      while (lineEnd < bufferSize && pageBuffer[lineEnd] != '\n') {
+        lineEnd++;
+      }
+    }
+
+    const bool isAtBufferEnd = (lineEnd == bufferSize);
+    const bool isEOF = (offset + bufferSize >= fileSize);
+    const bool lineComplete = (lineEnd < bufferSize) || isEOF || (isAtBufferEnd && bufferSize >= MAX_LINE_LENGTH);
     if (!lineComplete && !outLines.empty()) {
       // Incomplete line at chunk boundary and we already have content — stop here
       break;
     }
 
     size_t lineContentLen = lineEnd - pos;
-    bool hasCR = (lineContentLen > 0 && buffer[pos + lineContentLen - 1] == '\r');
+    bool hasCR = (lineContentLen > 0 && pageBuffer[pos + lineContentLen - 1] == '\r');
     size_t displayLen = hasCR ? lineContentLen - 1 : lineContentLen;
 
-    std::string rawLine(reinterpret_cast<char*>(buffer + pos), displayLen);
+    std::string rawLine(reinterpret_cast<char*>(pageBuffer.data() + pos), displayLen);
 
     // Check for code fence toggle
     bool wasFence = false;
@@ -363,8 +569,6 @@ bool MdReaderActivity::loadPageAtOffset(size_t offset, bool startInCodeBlock, st
   }
 
   endInCodeBlock = inCodeBlock;
-  free(buffer);
-
   return !outLines.empty();
 }
 

src/activities/reader/MdReaderTocSelectionActivity.cpp

@@ -0,0 +1,110 @@
+#include "MdReaderTocSelectionActivity.h"
+
+#include <algorithm>
+
+#include <GfxRenderer.h>
+#include <I18n.h>
+
+#include "components/UITheme.h"
+#include "fontIds.h"
+
+int MdReaderTocSelectionActivity::getTotalItems() const { return static_cast<int>(headings.size()); }
+
+int MdReaderTocSelectionActivity::getPageItems() const {
+  constexpr int lineHeight = 30;
+  const Rect contentRect = UITheme::getContentRect(renderer, true, false);
+  const int startY = 60 + contentRect.y;
+  const int availableHeight = contentRect.y + contentRect.height - startY - lineHeight;
+  return std::max(1, availableHeight / lineHeight);
+}
+
+void MdReaderTocSelectionActivity::onEnter() {
+  Activity::onEnter();
+
+  if (selectorIndex < 0 || selectorIndex >= getTotalItems()) {
+    selectorIndex = 0;
+  }
+
+  requestUpdate();
+}
+
+void MdReaderTocSelectionActivity::onExit() { Activity::onExit(); }
+
+void MdReaderTocSelectionActivity::loop() {
+  const int pageItems = getPageItems();
+  const int totalItems = getTotalItems();
+
+  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
+    if (selectorIndex >= 0 && selectorIndex < totalItems) {
+      setResult(PageResult{static_cast<uint32_t>(headings[selectorIndex].pageIndex)});
+    } else {
+      ActivityResult result;
+      result.isCancelled = true;
+      setResult(std::move(result));
+    }
+    finish();
+    return;
+  }
+
+  if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
+    ActivityResult result;
+    result.isCancelled = true;
+    setResult(std::move(result));
+    finish();
+    return;
+  }
+
+  buttonNavigator.onNextRelease([this, totalItems] {
+    selectorIndex = ButtonNavigator::nextIndex(selectorIndex, totalItems);
+    requestUpdate();
+  });
+
+  buttonNavigator.onPreviousRelease([this, totalItems] {
+    selectorIndex = ButtonNavigator::previousIndex(selectorIndex, totalItems);
+    requestUpdate();
+  });
+
+  buttonNavigator.onNextContinuous([this, totalItems, pageItems] {
+    selectorIndex = ButtonNavigator::nextPageIndex(selectorIndex, totalItems, pageItems);
+    requestUpdate();
+  });
+
+  buttonNavigator.onPreviousContinuous([this, totalItems, pageItems] {
+    selectorIndex = ButtonNavigator::previousPageIndex(selectorIndex, totalItems, pageItems);
+    requestUpdate();
+  });
+}
+
+void MdReaderTocSelectionActivity::render(RenderLock&&) {
+  renderer.clearScreen();
+
+  const Rect contentRect = UITheme::getContentRect(renderer, true, false);
+  const int pageItems = getPageItems();
+  const int totalItems = getTotalItems();
+
+  const int titleX =
+      contentRect.x +
+      (contentRect.width - renderer.getTextWidth(UI_12_FONT_ID, tr(STR_SELECT_CHAPTER), EpdFontFamily::BOLD)) / 2;
+  renderer.drawText(UI_12_FONT_ID, titleX, 15 + contentRect.y, tr(STR_SELECT_CHAPTER), true, EpdFontFamily::BOLD);
+
+  const int pageStartIndex = selectorIndex / pageItems * pageItems;
+  renderer.fillRect(contentRect.x, 60 + contentRect.y + (selectorIndex % pageItems) * 30 - 2, contentRect.width - 1,
+                    30);
+
+  for (int i = 0; i < pageItems; i++) {
+    int itemIndex = pageStartIndex + i;
+    if (itemIndex >= totalItems) break;
+    const int displayY = 60 + contentRect.y + i * 30;
+    const bool isSelected = (itemIndex == selectorIndex);
+
+    const auto& heading = headings[itemIndex];
+    const int indentSize = contentRect.x + 20 + (heading.level - 1) * 10;
+    const std::string title = renderer.truncatedText(UI_10_FONT_ID, heading.title.c_str(), contentRect.width - 40 - indentSize);
+    renderer.drawText(UI_10_FONT_ID, indentSize, displayY, title.c_str(), !isSelected);
+  }
+
+  const auto labels = mappedInput.mapLabels(tr(STR_BACK), tr(STR_SELECT), tr(STR_DIR_UP), tr(STR_DIR_DOWN));
+  GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+
+  renderer.displayBuffer();
+}

src/activities/reader/MdReaderTocSelectionActivity.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <vector>
+
+#include "MdReaderActivity.h"
+#include "../Activity.h"
+#include "util/ButtonNavigator.h"
+
+class MdReaderTocSelectionActivity final : public Activity {
+  std::vector<MdHeading> headings;
+  ButtonNavigator buttonNavigator;
+  int selectorIndex = 0;
+
+  int getPageItems() const;
+  int getTotalItems() const;
+
+ public:
+  explicit MdReaderTocSelectionActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
+                                       std::vector<MdHeading> headings, int currentHeadingIndex)
+      : Activity("MdReaderTocSelection", renderer, mappedInput), headings(std::move(headings)), selectorIndex(0) {
+    if (currentHeadingIndex >= 0 && currentHeadingIndex < static_cast<int>(headings.size())) {
+      selectorIndex = currentHeadingIndex;
+    }
+  }
+
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+  void render(RenderLock&&) override;
+};

src/activities/reader/ReaderActivity.cpp

@@ -167,7 +167,7 @@ void ReaderActivity::onEnter() {
       return;
     }
     onGoToXtcReader(std::move(xtc));
-  } else if (isMdFile(initialBookPath)) {
+  } else if (isMDFile(initialBookPath)) {
     auto txt = loadTxt(initialBookPath);
     if (!txt) {
       onGoBack();

test/md_parser/MdParserTest.cpp

@@ -0,0 +1,92 @@
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#include "../../lib/Md/MdParser.h"
+
+static int testsPassed = 0;
+static int testsFailed = 0;
+
+#define ASSERT_EQ(a, b)                                                         \
+  do {                                                                          \
+    if ((a) != (b)) {                                                           \
+      fprintf(stderr, "  FAIL: %s:%d: %s != %s\n", __FILE__, __LINE__, #a, #b); \
+      testsFailed++;                                                            \
+      return;                                                                   \
+    }                                                                           \
+  } while (0)
+
+#define PASS() testsPassed++
+
+static std::string flattenText(const std::vector<MdParser::Span>& spans) {
+  std::string result;
+  for (const auto& span : spans) {
+    result += span.text;
+  }
+  return result;
+}
+
+static bool allRegular(const std::vector<MdParser::Span>& spans) {
+  for (const auto& span : spans) {
+    if (span.style != EpdFontFamily::REGULAR) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void testSnakeCaseUnderscoresRemainLiteral() {
+  printf("testSnakeCaseUnderscoresRemainLiteral...\n");
+  auto spans = MdParser::parseInline("foo_bar_baz");
+  ASSERT_EQ(flattenText(spans), "foo_bar_baz");
+  ASSERT_EQ(allRegular(spans), true);
+  PASS();
+}
+
+void testUnderscoreWithinExpressionRemainsLiteral() {
+  printf("testUnderscoreWithinExpressionRemainsLiteral...\n");
+  auto spans = MdParser::parseInline("a_b + c_d");
+  ASSERT_EQ(flattenText(spans), "a_b + c_d");
+  ASSERT_EQ(allRegular(spans), true);
+  PASS();
+}
+
+void testUnderscoreEmphasisStillWorks() {
+  printf("testUnderscoreEmphasisStillWorks...\n");
+  auto spans = MdParser::parseInline("foo _bar_ baz");
+  ASSERT_EQ(flattenText(spans), "foo bar baz");
+  ASSERT_EQ(spans.size(), 3);
+  ASSERT_EQ(spans[1].style == EpdFontFamily::ITALIC || spans[1].style == EpdFontFamily::BOLD_ITALIC, true);
+  PASS();
+}
+
+void testAsteriskEmphasisStillWorks() {
+  printf("testAsteriskEmphasisStillWorks...\n");
+  auto spans = MdParser::parseInline("foo *bar* baz");
+  ASSERT_EQ(flattenText(spans), "foo bar baz");
+  ASSERT_EQ(spans.size(), 3);
+  ASSERT_EQ(spans[1].style == EpdFontFamily::ITALIC || spans[1].style == EpdFontFamily::BOLD_ITALIC, true);
+  PASS();
+}
+
+void testUnderscoreBoldWorks() {
+  printf("testUnderscoreBoldWorks...\n");
+  auto spans = MdParser::parseInline("foo __bar__ baz");
+  ASSERT_EQ(flattenText(spans), "foo bar baz");
+  ASSERT_EQ(spans.size(), 3);
+  ASSERT_EQ(spans[1].style == EpdFontFamily::BOLD || spans[1].style == EpdFontFamily::BOLD_ITALIC, true);
+  PASS();
+}
+
+int main() {
+  printf("=== Markdown Parser Tests ===\n\n");
+
+  testSnakeCaseUnderscoresRemainLiteral();
+  testUnderscoreWithinExpressionRemainsLiteral();
+  testUnderscoreEmphasisStillWorks();
+  testAsteriskEmphasisStillWorks();
+  testUnderscoreBoldWorks();
+
+  printf("\n=== Results: %d passed, %d failed ===\n", testsPassed, testsFailed);
+  return testsFailed > 0 ? 1 : 0;
+}