commit 09e10f6e3bceffd7299254c3076450ef5f218032
Author: Sascha Kühl <s.kuehl@tms-bonn.de>
Date:   Fri Oct 10 12:29:17 2025 +0200

    initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..485dee6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.idea
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..b57d8af
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,8 @@
+cmake_minimum_required(VERSION 3.10)
+project(rsql_parser)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+add_subdirectory(src)
+
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..94baa6b
--- /dev/null
+++ b/README.md
@@ -0,0 +1,21 @@
+# RSQL Parser (C++) with SQL WHERE Generator
+
+This small example demonstrates:
+- A lexer + parser for a subset of RSQL (supports `;` AND, `,` OR, parentheses).
+- `=in=` and `=out=` list operators.
+- An AST implementing `accept()` for the Visitor pattern.
+- A `SQLBuilderVisitor` that generates an SQL `WHERE` clause.
+
+Build:
+```bash
+mkdir build && cd build
+cmake ..
+cmake --build .
+```
+
+Run (example):
+```bash
+./rsql_parser "(status=in=(OPEN,CLOSED);priority==HIGH),category=out=(internal,test)"
+```
+
+The program prints the AST (evaluator) and the generated SQL WHERE clause.
\ No newline at end of file
diff --git a/include/matador/rsql/binary_condition_node.hpp b/include/matador/rsql/binary_condition_node.hpp
new file mode 100644
index 0000000..06a42cc
--- /dev/null
+++ b/include/matador/rsql/binary_condition_node.hpp
@@ -0,0 +1,50 @@
+#ifndef RSQL_PARSER_BINARY_CONDITION_NODE_HPP
+#define RSQL_PARSER_BINARY_CONDITION_NODE_HPP
+
+#include "node.hpp"
+
+#include <map>
+#include <string>
+
+namespace matador::rsql {
+enum class binary_operator {
+    EQUALS,
+    NOT_EQUALS,
+    GREATER_THAN,
+    GREATER_THAN_OR_EQUAL,
+    LESS_THAN,
+    LESS_THAN_OR_EQUAL,
+};
+
+static const std::map<std::string, binary_operator> binary_operators = {
+    { "==", binary_operator::EQUALS },
+    { "!=", binary_operator::NOT_EQUALS },
+    { ">", binary_operator::GREATER_THAN },
+    { "=gt*", binary_operator::GREATER_THAN },
+    { ">=", binary_operator::GREATER_THAN_OR_EQUAL },
+    { "=ge=", binary_operator::GREATER_THAN_OR_EQUAL },
+    { "<", binary_operator::LESS_THAN },
+    { "=lt=", binary_operator::LESS_THAN },
+    { "<=", binary_operator::LESS_THAN_OR_EQUAL },
+    { "=le=", binary_operator::LESS_THAN_OR_EQUAL }
+};
+
+class node_visitor;
+class binary_condition_node final : public node {
+public:
+    binary_condition_node(std::string field, binary_operator op, std::string value);
+
+    void accept(node_visitor& visitor) const override;
+
+    const std::string& field() const;
+    binary_operator operand() const;
+    const std::string& value() const;
+
+private:
+    std::string field_;
+    binary_operator op_;
+    std::string value_;
+};
+
+};
+#endif //RSQL_PARSER_BINARY_CONDITION_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/collection_condition_node.hpp b/include/matador/rsql/collection_condition_node.hpp
new file mode 100644
index 0000000..047c0bb
--- /dev/null
+++ b/include/matador/rsql/collection_condition_node.hpp
@@ -0,0 +1,38 @@
+#ifndef RSQL_PARSER_COLLECTION_CONDITION_NODE_HPP
+#define RSQL_PARSER_COLLECTION_CONDITION_NODE_HPP
+
+#include "node.hpp"
+
+#include <map>
+#include <string>
+#include <vector>
+
+namespace matador::rsql {
+enum class collection_operator {
+    IN,
+    OUT
+};
+
+static const std::map<std::string, collection_operator> collection_operators = {
+    { "=in=", collection_operator::IN },
+    { "=out=", collection_operator::OUT }
+};
+
+
+class collection_condition_node final : public node {
+public:
+    collection_condition_node(std::string field, collection_operator op, std::vector<std::string> value);
+
+    void accept(node_visitor& visitor) const override;
+
+    const std::string& field() const;
+    collection_operator operand() const;
+    const std::vector<std::string>& values() const;
+
+private:
+    std::string field_;
+    collection_operator op_;
+    std::vector<std::string> value_;
+};
+}
+#endif //RSQL_PARSER_COLLECTION_CONDITION_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/lexer.hpp b/include/matador/rsql/lexer.hpp
new file mode 100644
index 0000000..ba3feca
--- /dev/null
+++ b/include/matador/rsql/lexer.hpp
@@ -0,0 +1,13 @@
+#ifndef RSQL_PARSER_LEXER_HPP
+#define RSQL_PARSER_LEXER_HPP
+
+#include "token.hpp"
+
+#include <regex>
+#include <string>
+#include <vector>
+
+namespace matador::rsql::lexer {
+std::vector<token> tokenize(const std::string& input);
+}
+#endif //RSQL_PARSER_LEXER_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/logical_node.hpp b/include/matador/rsql/logical_node.hpp
new file mode 100644
index 0000000..b6dac06
--- /dev/null
+++ b/include/matador/rsql/logical_node.hpp
@@ -0,0 +1,33 @@
+#ifndef RSQL_PARSER_LOGICAL_NODE_HPP
+#define RSQL_PARSER_LOGICAL_NODE_HPP
+
+#include "node.hpp"
+
+#include <string>
+#include <vector>
+#include <memory>
+
+namespace matador::rsql {
+enum class logical_operator {
+    AND,
+    OR,
+};
+
+class node_visitor;
+
+class logical_node final : public node {
+public:
+    explicit logical_node(logical_operator op);
+    void accept(node_visitor& visitor) const override;
+
+    const std::vector<std::shared_ptr<node>>& children() const;
+    logical_operator operand() const;
+
+private:
+    friend class parser;
+    logical_operator op_; // ";" for AND, "," for OR
+    std::vector<std::shared_ptr<node>> children_;
+};
+
+}
+#endif //RSQL_PARSER_LOGICAL_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/node.hpp b/include/matador/rsql/node.hpp
new file mode 100644
index 0000000..b4a215d
--- /dev/null
+++ b/include/matador/rsql/node.hpp
@@ -0,0 +1,12 @@
+#ifndef RSQL_PARSER_NODE_HPP
+#define RSQL_PARSER_NODE_HPP
+
+namespace matador::rsql {
+class node_visitor;
+class node {
+public:
+    virtual ~node() = default;
+    virtual void accept(node_visitor& visitor) const = 0;
+};
+}
+#endif //RSQL_PARSER_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/node_visitor.hpp b/include/matador/rsql/node_visitor.hpp
new file mode 100644
index 0000000..f81227b
--- /dev/null
+++ b/include/matador/rsql/node_visitor.hpp
@@ -0,0 +1,19 @@
+#ifndef RSQL_PARSER_NODE_VISITOR_HPP
+#define RSQL_PARSER_NODE_VISITOR_HPP
+
+namespace matador::rsql {
+
+class binary_condition_node;
+class collection_condition_node;
+class logical_node;
+
+class node_visitor {
+public:
+    virtual ~node_visitor() = default;
+    virtual void visit(const binary_condition_node& node) = 0;
+    virtual void visit(const collection_condition_node& node) = 0;
+    virtual void visit(const logical_node& node) = 0;
+
+};
+}
+#endif //RSQL_PARSER_NODE_VISITOR_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/parser.hpp b/include/matador/rsql/parser.hpp
new file mode 100644
index 0000000..9ecf5ce
--- /dev/null
+++ b/include/matador/rsql/parser.hpp
@@ -0,0 +1,39 @@
+#ifndef RSQL_PARSER_PARSER_HPP
+#define RSQL_PARSER_PARSER_HPP
+
+#include "token.hpp"
+#include "token_type.hpp"
+
+#include <memory>
+#include <vector>
+
+namespace matador::rsql {
+class node;
+
+class parser {
+public:
+    explicit parser(std::vector<token> t);
+
+    std::shared_ptr<node> parse();
+
+private:
+    // OR level
+    std::shared_ptr<node> parse_or_expression();
+
+    // AND level
+    std::shared_ptr<node> parse_and_expression();
+
+    // Primary: parenthesis or condition
+    std::shared_ptr<node> parse_primary();
+    std::shared_ptr<node> parse_condition();
+
+    bool match(const std::vector<token_type>& types);
+
+    const token& previous() const;
+
+private:
+    std::vector<token> tokens_;
+    size_t current_size_ = 0;
+};
+}
+#endif //RSQL_PARSER_PARSER_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/token.hpp b/include/matador/rsql/token.hpp
new file mode 100644
index 0000000..ce283d5
--- /dev/null
+++ b/include/matador/rsql/token.hpp
@@ -0,0 +1,14 @@
+#ifndef RSQL_PARSER_TOKEN_HPP
+#define RSQL_PARSER_TOKEN_HPP
+
+#include "token_type.hpp"
+
+#include <string>
+
+namespace matador::rsql {
+struct token {
+    token_type type;
+    std::string value;
+};
+}
+#endif //RSQL_PARSER_TOKEN_HPP
\ No newline at end of file
diff --git a/include/matador/rsql/token_type.hpp b/include/matador/rsql/token_type.hpp
new file mode 100644
index 0000000..16d7f63
--- /dev/null
+++ b/include/matador/rsql/token_type.hpp
@@ -0,0 +1,17 @@
+#ifndef RSQL_PARSER_TOKEN_TYPE_HPP
+#define RSQL_PARSER_TOKEN_TYPE_HPP
+
+namespace matador::rsql {
+enum class token_type {
+    IDENTIFIER,
+    OPERATOR,
+    VALUE,
+    LOGICAL_AND,
+    LOGICAL_OR,
+    OPEN_PAREN,
+    CLOSE_PAREN,
+    UNKNOWN
+};
+}
+
+#endif //RSQL_PARSER_TOKEN_TYPE_HPP
\ No newline at end of file
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
new file mode 100644
index 0000000..5eb34e5
--- /dev/null
+++ b/src/CMakeLists.txt
@@ -0,0 +1,25 @@
+SET(SOURCE
+        ../include/matador/rsql/binary_condition_node.hpp
+        ../include/matador/rsql/collection_condition_node.hpp
+        ../include/matador/rsql/lexer.hpp
+        ../include/matador/rsql/logical_node.hpp
+        ../include/matador/rsql/node.hpp
+        ../include/matador/rsql/node_visitor.hpp
+        ../include/matador/rsql/parser.hpp
+        ../include/matador/rsql/token.hpp
+        ../include/matador/rsql/token_type.hpp
+        rsql/binary_condition_node.cpp
+        rsql/collection_condition_node.cpp
+        rsql/lexer.cpp
+        rsql/logical_node.cpp
+        rsql/parser.cpp
+)
+
+add_library(matador-rsql STATIC ${SOURCE})
+
+target_include_directories(matador-rsql PUBLIC ../include)
+
+add_executable(rsql_parser main.cpp)
+target_include_directories(rsql_parser PUBLIC ../include)
+target_link_libraries(rsql_parser matador-rsql)
+
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..34f7bf4
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,198 @@
+#include "matador/rsql/binary_condition_node.hpp"
+#include "matador/rsql/collection_condition_node.hpp"
+#include "matador/rsql/lexer.hpp"
+#include "matador/rsql/logical_node.hpp"
+#include "matador/rsql/node_visitor.hpp"
+#include "matador/rsql/parser.hpp"
+
+#include <iostream>
+
+// ---------------- Evaluator Visitor (prints AST) ----------------
+class Evaluator final : public matador::rsql::node_visitor {
+public:
+    void visit(const matador::rsql::binary_condition_node& node) override {
+        std::cout << "Condition: " << node.field() << " " << to_string(node.operand()) << " " << node.value() << "\n";
+    }
+
+    void visit( const matador::rsql::collection_condition_node& node ) override {
+        std::cout << "Condition: " << node.field() << " " << to_string(node.operand()) << " ";
+        std::cout << "(";
+        for (size_t i = 0; i < node.values().size(); ++i) {
+            std::cout << node.values()[i];
+            if (i + 1 < node.values().size()) std::cout << ",";
+        }
+        std::cout << ")\n";
+    }
+
+    void visit(const matador::rsql::logical_node& node) override {
+        std::cout << "Logical (" << (node.operand() == matador::rsql::logical_operator::AND ? "AND" : "OR") << ")\n";
+        for (const auto& child : node.children()) {
+            child->accept(*this);
+        }
+    }
+
+private:
+    static std::string to_string(const matador::rsql::binary_operator op) {
+        static std::map<matador::rsql::binary_operator, std::string> bin_to_string {
+            { matador::rsql::binary_operator::EQUALS, "==" },
+            { matador::rsql::binary_operator::NOT_EQUALS, "!=" },
+            { matador::rsql::binary_operator::GREATER_THAN, ">" },
+            { matador::rsql::binary_operator::GREATER_THAN_OR_EQUAL, ">=" },
+            { matador::rsql::binary_operator::LESS_THAN, "<" },
+            { matador::rsql::binary_operator::LESS_THAN_OR_EQUAL, "<=" },
+        };
+
+        return bin_to_string.at(op);
+    }
+
+    static std::string to_string(const matador::rsql::collection_operator op) {
+        static std::map<matador::rsql::collection_operator, std::string> col_to_string {
+            { matador::rsql::collection_operator::IN, "=IN=" },
+            { matador::rsql::collection_operator::OUT, "=OUT=" }
+        };
+
+        return col_to_string.at(op);
+    }
+};
+
+// ---------------- SQLBuilderVisitor ----------------
+class SQLBuilderVisitor final : public matador::rsql::node_visitor {
+public:
+    std::string result;
+
+    void visit(const matador::rsql::binary_condition_node& node) override {
+        result += "(" + field(node.field()) + " " + binary_op_string(node.operand(), node.value()) + ")";
+    }
+
+    void visit( const matador::rsql::collection_condition_node& node ) override {
+        result += "(" + field(node.field()) + " " + collection_op_string(node.operand(), node.values()) + ")";
+    }
+
+    void visit(const matador::rsql::logical_node& node) override {
+        // Build children SQL and join
+        std::vector<std::string> parts;
+        for (const auto& child : node.children()) {
+            SQLBuilderVisitor sub;
+            child->accept(sub);
+            parts.push_back(sub.result);
+        }
+        const std::string operand = (node.operand() == matador::rsql::logical_operator::AND ? " AND " : " OR ");
+        result += "(";
+        for (size_t i = 0; i < parts.size(); ++i) {
+            result += parts[i];
+            if (i + 1 < parts.size()) {
+                result += operand;
+            }
+        }
+        result += ")";
+    }
+
+private:
+    static std::string escape_sql(const std::string& s) {
+        std::string out;
+        out.reserve(s.size() + 2);
+        for (const char c : s) {
+            if (c == '\'') out.push_back('\''); // double single-quote
+            out.push_back(c);
+        }
+        return out;
+    }
+
+    static bool is_number(const std::string& s) {
+        if (s.empty()) {
+            return false;
+        }
+        // allow optional leading '-' and digits, optional decimal point
+        size_t i = 0;
+        if (s[0] == '-') i = 1;
+        bool seenDigit = false;
+        bool seenDot = false;
+        for (; i < s.size(); ++i) {
+            if (std::isdigit(static_cast<unsigned char>(s[i]))) seenDigit = true;
+            else if (s[i] == '.' && !seenDot) seenDot = true;
+            else return false;
+        }
+        return seenDigit;
+    }
+
+    static std::string quote(const std::string& str) {
+        if (is_number(str)) {
+            return str;
+        }
+        return std::string("'") + escape_sql(str) + std::string("'");
+    }
+
+    static std::string field(const std::string& f) {
+        // Todo: add quoting rules
+        return f;
+    }
+
+    static std::string binary_op_string(const matador::rsql::binary_operator op, const std::string& val) {
+        using namespace matador::rsql;
+        switch (op) {
+            case binary_operator::EQUALS:
+                return "= " + quote(val);
+            case binary_operator::NOT_EQUALS:
+                return "<> " + quote(val);
+            case binary_operator::GREATER_THAN:
+                return "> " + quote(val);
+            case binary_operator::GREATER_THAN_OR_EQUAL:
+                return ">= " + quote(val);
+            case binary_operator::LESS_THAN:
+                return "< " + quote(val);
+            case binary_operator::LESS_THAN_OR_EQUAL:
+                return "<= " + quote(val);
+            default:
+                return "??";
+        }
+    }
+
+    static std::string collection_op_string(const matador::rsql::collection_operator op, const std::vector<std::string>& list) {
+        if (list.empty()) {
+            return (op == matador::rsql::collection_operator::OUT ? "NOT IN (NULL)" : "IN (NULL)");
+        }
+        std::string joined;
+        joined += "(";
+        for (size_t i = 0; i < list.size(); ++i) {
+            joined += quote(list[i]);
+            if (i + 1 < list.size()) joined += ", ";
+        }
+        joined += ")";
+        if (op == matador::rsql::collection_operator::OUT) {
+            return "IN " + joined;
+        }
+        return "NOT IN " + joined;
+    }
+};
+
+// ---------------- Main / usage ----------------
+int main(const int argc, char** argv) {
+    using namespace matador::rsql;
+    std::string input;
+    if (argc >= 2) {
+        input = argv[1];
+    } else {
+        // example default
+        input = "(status=in=(OPEN,CLOSED);priority==HIGH),category=out=(internal,test)";
+        std::cout << "No query provided, using default example:\n" << input << "\n\n";
+    }
+
+    try {
+        const auto tokens = lexer::tokenize(input);
+        parser p(tokens);
+        const auto ast = p.parse();
+
+        std::cout << "=== AST (Evaluator) ===\n";
+        Evaluator ev;
+        ast->accept(ev);
+
+        std::cout << "\n=== SQL WHERE clause ===\n";
+        SQLBuilderVisitor sql;
+        ast->accept(sql);
+        std::cout << sql.result << "\n";
+    } catch (const std::exception& ex) {
+        std::cerr << "Error: " << ex.what() << "\n";
+        return 2;
+    }
+    return 0;
+}
diff --git a/src/rsql/binary_condition_node.cpp b/src/rsql/binary_condition_node.cpp
new file mode 100644
index 0000000..949f188
--- /dev/null
+++ b/src/rsql/binary_condition_node.cpp
@@ -0,0 +1,26 @@
+#include "matador/rsql/binary_condition_node.hpp"
+#include "matador/rsql/node_visitor.hpp"
+
+namespace matador::rsql {
+binary_condition_node::binary_condition_node(std::string field, const binary_operator op, std::string value)
+: field_(std::move(field))
+, op_(op)
+, value_(std::move(value))
+{}
+
+inline void binary_condition_node::accept( node_visitor& visitor ) const {
+    visitor.visit(*this);
+}
+
+const std::string& binary_condition_node::field() const {
+    return field_;
+}
+
+binary_operator binary_condition_node::operand() const {
+    return op_;
+}
+
+const std::string& binary_condition_node::value() const {
+    return value_;
+}
+}
\ No newline at end of file
diff --git a/src/rsql/collection_condition_node.cpp b/src/rsql/collection_condition_node.cpp
new file mode 100644
index 0000000..780b59b
--- /dev/null
+++ b/src/rsql/collection_condition_node.cpp
@@ -0,0 +1,27 @@
+#include "matador/rsql/collection_condition_node.hpp"
+
+#include "matador/rsql/node_visitor.hpp"
+
+namespace matador::rsql {
+collection_condition_node::collection_condition_node(std::string field, const collection_operator op, std::vector<std::string> value)
+: field_(std::move(field))
+, op_(op)
+, value_(std::move(value))
+{}
+
+void collection_condition_node::accept(node_visitor& visitor) const {
+    visitor.visit(*this);
+}
+
+const std::string& collection_condition_node::field() const {
+    return field_;
+}
+
+collection_operator collection_condition_node::operand() const {
+    return op_;
+}
+
+const std::vector<std::string>& collection_condition_node::values() const {
+    return value_;
+}
+}
\ No newline at end of file
diff --git a/src/rsql/lexer.cpp b/src/rsql/lexer.cpp
new file mode 100644
index 0000000..4221a8c
--- /dev/null
+++ b/src/rsql/lexer.cpp
@@ -0,0 +1,38 @@
+#include "matador/rsql/lexer.hpp"
+#include "matador/rsql/token_type.hpp"
+
+namespace matador::rsql::lexer {
+std::vector<token> tokenize( const std::string& input ) {
+    std::vector<token> tokens;
+
+    // Pattern catches: =in=, =out=, operators, quoted strings, identifiers, parentheses, commas/semicolons
+    std::regex tokenRegex(R"((=in=|=out=|[=!><~]+)|('[^']*'|"[^"]*")|(\()|(\))|(;|,)|([A-Za-z_]\w*)|([^ \t\n\r]+))");
+    auto begin = std::sregex_iterator(input.begin(), input.end(), tokenRegex);
+    auto end = std::sregex_iterator();
+
+    for (auto it = begin; it != end; ++it) {
+        const std::smatch& m = *it;
+
+        if (std::string match = m.str(); match == ";") {
+            tokens.push_back({token_type::LOGICAL_AND, match});
+        } else if (match == ",") {
+            tokens.push_back({token_type::LOGICAL_OR, match});
+        } else if (match == "(") {
+            tokens.push_back({token_type::OPEN_PAREN, match});
+        } else if (match == ")") {
+            tokens.push_back({token_type::CLOSE_PAREN, match});
+        } else if (std::regex_match(match, std::regex(R"(=in=|=out=|[=!><~]+)"))) {
+            tokens.push_back({token_type::OPERATOR, match});
+        } else if ((match.size() >= 2 && ((match.front() == '\'' && match.back() == '\'') ||
+                                          (match.front() == '"' && match.back() == '"')))) {
+            tokens.push_back({token_type::VALUE, match.substr(1, match.size() - 2)});
+        } else if (std::regex_match(match, std::regex(R"([A-Za-z_]\w*)"))) {
+            tokens.push_back({token_type::IDENTIFIER, match});
+        } else {
+            tokens.push_back({token_type::VALUE, match});
+        }
+    }
+
+    return tokens;
+}
+}
\ No newline at end of file
diff --git a/src/rsql/logical_node.cpp b/src/rsql/logical_node.cpp
new file mode 100644
index 0000000..6b00a6c
--- /dev/null
+++ b/src/rsql/logical_node.cpp
@@ -0,0 +1,21 @@
+#include "matador/rsql/logical_node.hpp"
+#include "matador/rsql/node_visitor.hpp"
+
+namespace matador::rsql {
+
+logical_node::logical_node(const logical_operator op)
+: op_(op) {}
+
+void logical_node::accept( node_visitor& visitor ) const {
+    visitor.visit(*this);
+}
+
+logical_operator logical_node::operand() const {
+    return op_;
+}
+
+const std::vector<std::shared_ptr<node>>& logical_node::children() const {
+    return children_;
+}
+
+}
\ No newline at end of file
diff --git a/src/rsql/parser.cpp b/src/rsql/parser.cpp
new file mode 100644
index 0000000..8cda9d0
--- /dev/null
+++ b/src/rsql/parser.cpp
@@ -0,0 +1,111 @@
+#include "matador/rsql/parser.hpp"
+
+#include "matador/rsql/binary_condition_node.hpp"
+#include "matador/rsql/collection_condition_node.hpp"
+#include "matador/rsql/logical_node.hpp"
+
+#include <map>
+#include <stdexcept>
+
+namespace matador::rsql {
+parser::parser( std::vector<token> t )
+: tokens_(std::move(t)) {}
+
+std::shared_ptr<node> parser::parse() {
+    if (tokens_.empty()) {
+        throw std::runtime_error("Empty input");
+    }
+    auto res = parse_or_expression();
+    if (current_size_ != tokens_.size()) {
+        throw std::runtime_error("Unexpected token after end: " + tokens_[current_size_].value);
+    }
+    return res;
+}
+
+std::shared_ptr<node> parser::parse_or_expression() {
+    auto node = parse_and_expression();
+    while (match({token_type::LOGICAL_OR})) {
+        std::string op = previous().value;
+        const auto logical = std::make_shared<logical_node>(logical_operator::OR);
+        logical->children_.push_back(node);
+        logical->children_.push_back(parse_and_expression());
+        node = logical;
+    }
+    return node;
+}
+
+std::shared_ptr<node> parser::parse_and_expression() {
+    auto node = parse_primary();
+    while (match({token_type::LOGICAL_AND})) {
+        std::string op = previous().value;
+        const auto logical = std::make_shared<logical_node>(logical_operator::AND);
+        logical->children_.push_back(node);
+        logical->children_.push_back(parse_primary());
+        node = logical;
+    }
+    return node;
+}
+
+std::shared_ptr<node> parser::parse_primary() {
+    if (match({token_type::OPEN_PAREN})) {
+        auto node = parse_or_expression();
+        if (!match({token_type::CLOSE_PAREN})) {
+            throw std::runtime_error("Missing closing parenthesis");
+        }
+        return node;
+    }
+    return parse_condition();
+}
+
+std::shared_ptr<node> parser::parse_condition() {
+    if (!match({token_type::IDENTIFIER})) {
+        throw std::runtime_error("Expected field name");
+    }
+    std::string field = previous().value;
+
+    if (!match({token_type::OPERATOR})) {
+        throw std::runtime_error("Expected operator after field");
+    }
+
+    const std::string op = previous().value;
+    if (op == "=in=" || op == "=out=") {
+        if (!match({token_type::OPEN_PAREN})) {
+            throw std::runtime_error("Expected '(' after " + op);
+        }
+        std::vector<std::string> values;
+        bool first = true;
+        while (!match({token_type::CLOSE_PAREN})) {
+            if (!first) {
+                // accept comma as separator: tokens use LOGICAL_OR for comma in lexer
+                if (!match({token_type::LOGICAL_OR})) {
+                    throw std::runtime_error("Expected ',' between list values");
+                }
+            }
+            if (!match({token_type::VALUE, token_type::IDENTIFIER})) {
+                throw std::runtime_error("Expected value in list");
+            }
+            values.push_back(previous().value);
+            first = false;
+        }
+        return std::make_shared<collection_condition_node>(field, collection_operators.at(op), values);
+    }
+
+    if (!match({token_type::VALUE, token_type::IDENTIFIER})) {
+        throw std::runtime_error("Expected value after operator");
+    }
+    return std::make_shared<binary_condition_node>(field, binary_operators.at(op), previous().value);
+}
+
+bool parser::match( const std::vector<token_type>& types ) {
+    if (current_size_ < tokens_.size() &&
+        std::find(types.begin(), types.end(), tokens_[current_size_].type) != types.end()) {
+        ++current_size_;
+        return true;
+    }
+    return false;
+}
+
+const token& parser::previous() const {
+    return tokens_[current_size_ - 1];
+}
+}
\ No newline at end of file