feat: implement DOM tree builder to transform HTML tokens into a hierarchical structure

3 files changed, 80 insertions, 1 deletions

diff --git a/include/ricochet/parser/dom_tree.hh b/include/ricochet/parser/dom_tree.hh
new file mode 100644
index 0000000..b1e4812
--- /dev/null
+++ b/include/ricochet/parser/dom_tree.hh
@@ -0,0 +1,35 @@
+/*
+ * Ricochet - A minimalist CLI web browser for fast, distraction-free navigation.
+ * Copyright (C) 2026  Richard Qin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+namespace ricochet::parser {
+
+/**
+ * @brief DOM Node. Pure value semantics, no pointers.
+ */
+struct DomNode {
+    std::string tag_name{};    // If empty, it's a pure text node
+    std::string text_content{}; // Only meaningful when tag_name is empty
+    std::vector<DomNode> children{}; // Recursive child nodes list
+};
+
+} // namespace ricochet::parser
\ No newline at end of file
diff --git a/include/ricochet/parser/html_lexer.hh b/include/ricochet/parser/html_lexer.hh
index f97bcfa..2cfdda9 100644
--- a/include/ricochet/parser/html_lexer.hh
+++ b/include/ricochet/parser/html_lexer.hh
@@ -25,7 +25,7 @@
 
 namespace ricochet::parser {
 
-    struct TextToken {
+struct TextToken {
     std::string content{};
 };
 
diff --git a/include/ricochet/parser/tree_builder.hh b/include/ricochet/parser/tree_builder.hh
new file mode 100644
index 0000000..4adbc4d
--- /dev/null
+++ b/include/ricochet/parser/tree_builder.hh
@@ -0,0 +1,44 @@
+/*
+ * Ricochet - A minimalist CLI web browser for fast, distraction-free navigation.
+ * Copyright (C) 2026  Richard Qin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "ricochet/parser/dom_tree.hh"
+#include "ricochet/parser/html_lexer.hh"
+
+#include <vector>
+
+namespace ricochet::parser {
+
+class TreeBuilder {
+public:
+    TreeBuilder() = default;
+    ~TreeBuilder() = default;
+
+    TreeBuilder(const TreeBuilder&) = delete;
+    TreeBuilder& operator=(const TreeBuilder&) = delete;
+    TreeBuilder(TreeBuilder&&) = delete;
+    TreeBuilder& operator=(TreeBuilder&&) = delete;
+
+    /**
+     * @brief Assemble a one-dimensional token sequence into a multi-dimensional DOM tree
+     */
+    DomNode build(const std::vector<HtmlToken>& tokens) const;
+};
+
+} // namespace ricochet::parser
\ No newline at end of file