add Markdown (.md) file reader with formatting support #1698 by dcherrera

lib/Md/MdParser.h

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <EpdFontFamily.h>
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace MdParser {
+
+struct Span {
+  std::string text;
+  EpdFontFamily::Style style;
+};
+
+enum class BlockType : uint8_t {
+  Paragraph,
+  Header1,
+  Header2,
+  Header3,
+  UnorderedList,
+  OrderedList,
+  Blockquote,
+  CodeBlock,
+  HorizontalRule,
+  BlankLine
+};
+
+struct ParsedLine {
+  BlockType blockType;
+  std::vector<Span> spans;
+  std::string listPrefix;   // "• " or "1. " etc.
+  uint8_t indentLevel = 0;  // Nesting depth (each 2 spaces = 1 level)
+};
+
+// Parse a single raw line of markdown into block type and styled spans.
+// |inCodeBlock| indicates whether the line is inside a fenced code block.
+ParsedLine parseLine(const std::string& rawLine, bool inCodeBlock);
+
+// Returns true if the line is a code fence (``` with optional language tag).
+bool isCodeFence(const std::string& line);
+
+// Parse inline markdown formatting (bold, italic, code spans, links, images).
+std::vector<Span> parseInline(const std::string& text);
+
+}  // namespace MdParser