2 files changed, 120 insertions, 14 deletions

diff --git a/include/openvic-dataloader/csv/LineObject.hpp b/include/openvic-dataloader/csv/LineObject.hpp
index c6d8e2a..b9ee9a5 100644
--- a/include/openvic-dataloader/csv/LineObject.hpp
+++ b/include/openvic-dataloader/csv/LineObject.hpp
@@ -4,7 +4,6 @@
 #include <cctype>
 #include <cstddef>
 #include <cstdint>
-#include <functional>
 #include <initializer_list>
 #include <optional>
 #include <ostream>
@@ -14,6 +13,7 @@
 #include <utility>
 #include <vector>
 
+#include <openvic-dataloader/csv/ValueNode.hpp>
 #include <openvic-dataloader/detail/VectorConstexpr.hpp>
 
 namespace ovdl::csv {
@@ -28,13 +28,13 @@ namespace ovdl::csv {
 	/// ;a;b;c -> 0,4+ == ""
 	///
 	/// If this is incorrect, please report an issue.
-	class LineObject final : public std::vector<std::pair<std::uint32_t, std::string>> {
+	class LineObject final : public std::vector<ValueNode> {
 	public:
 		// Stored position of value
-		using position_type = std::uint32_t;
+		using position_type = ValueNode::position_type;
 		// Value
-		using inner_value_type = std::string;
-		using container_type = std::vector<std::pair<position_type, inner_value_type>>;
+		using inner_value_type = ValueNode;
+		using container_type = std::vector<ValueNode>;
 
 		OVDL_VECTOR_CONSTEXPR LineObject() = default;
 		OVDL_VECTOR_CONSTEXPR LineObject(LineObject&) = default;
@@ -57,18 +57,42 @@ namespace ovdl::csv {
 
 		/// Special Functionality
 		/// Retrieves value, produces "" for empty values
-		constexpr std::string_view get_value_for(std::size_t position) const {
+		constexpr std::string get_value_for(std::size_t position) const {
 			if (position < _prefix_end || position >= _suffix_end) return "";
-			for (const auto& [pos, val] : *this) {
-				if (pos == position) return val;
+			for (const auto& object : *this) {
+				if (object.get_position() == position) return object.make();
 			}
 			return "";
 		}
-		/// Tries to retrieve reference, produces nullopt for empty values
-		constexpr std::optional<const std::reference_wrapper<const std::string>> try_get_string_at(std::size_t position) const {
+		/// Tries to retrieve string, produces nullopt for empty values
+		constexpr std::optional<const std::string> try_get_string_at(std::size_t position) const {
 			if (position < _prefix_end || position >= _suffix_end) return std::nullopt;
-			for (const auto& [pos, val] : *this) {
-				if (pos == position) return std::cref(val);
+			for (const auto& object : *this) {
+				if (object.get_position() == position) return object.make();
+			}
+			return std::nullopt;
+		}
+		constexpr std::optional<const std::reference_wrapper<const ValueNode>> try_get_object_at(std::size_t position) const {
+			if (position < _prefix_end || position >= _suffix_end) return std::nullopt;
+			for (const auto& object : *this) {
+				if (object.get_position() == position) return object;
+			}
+			return std::nullopt;
+		}
+
+		/// Retrieves value, produces "" for empty values
+		constexpr std::string_view get_value_for(std::size_t position, const IsMap<std::string> auto& map) const {
+			if (position < _prefix_end || position >= _suffix_end) return "";
+			for (const auto& object : *this) {
+				if (object.get_position() == position) return object.make_from_map(map);
+			}
+			return "";
+		}
+		/// Tries to retrieve string, produces nullopt for empty values
+		constexpr std::optional<const std::string> try_get_string_at(std::size_t position, const IsMap<std::string> auto& map) const {
+			if (position < _prefix_end || position >= _suffix_end) return std::nullopt;
+			for (const auto& object : *this) {
+				if (object.get_position() == position) return object.make_from_map(map);
 			}
 			return std::nullopt;
 		}
@@ -91,8 +115,9 @@ namespace ovdl::csv {
 	inline std::ostream& operator<<(std::ostream& stream, const LineObject& line) {
 		static const char SEP = ';';
 		LineObject::position_type sep_index = 0;
-		for (const auto& [pos, val] : line) {
-			while (sep_index < pos) {
+		for (const auto& object : line) {
+			const std::string& val = object.make();
+			while (sep_index < object.get_position()) {
 				stream << SEP;
 				sep_index++;
 			}
diff --git a/include/openvic-dataloader/csv/ValueNode.hpp b/include/openvic-dataloader/csv/ValueNode.hpp
new file mode 100644
index 0000000..e66dac0
--- /dev/null
+++ b/include/openvic-dataloader/csv/ValueNode.hpp
@@ -0,0 +1,81 @@
+#pragma once
+
+#include <concepts>
+#include <cstdint>
+#include <initializer_list>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <type_traits>
+#include <variant>
+#include <vector>
+
+#include <fmt/compile.h>
+#include <fmt/core.h>
+#include <fmt/format.h>
+
+namespace ovdl::csv {
+	template<typename T, typename Value>
+	concept IsMap =
+		requires(T t) {
+			{ t.begin() } -> std::same_as<typename T::const_iterator>;
+			{ t.end() } -> std::same_as<typename T::const_iterator>;
+			{ t.empty() } -> std::same_as<bool>;
+			{ t.size() } -> std::same_as<typename T::size_type>;
+			{ t.at("") } -> std::same_as<const Value&>;
+			{ t.find("") } -> std::same_as<typename T::const_iterator>;
+			{ t[""] } -> std::same_as<const Value&>;
+		};
+
+	class ValueNode {
+	public:
+		struct Placeholder {
+			static constexpr char ESCAPE_CHAR = '$';
+			static constexpr std::string_view ESCAPE_STR = std::string_view { &ESCAPE_CHAR, 1 };
+
+			std::string value;
+			inline std::string as_string(std::string_view prefix = ESCAPE_STR, std::optional<std::string_view> suffix = std::nullopt) const {
+				return fmt::format(FMT_COMPILE("{}{}{}"), prefix, value, suffix.value_or(prefix));
+			}
+		};
+
+		using internal_value_type = std::variant<std::string, Placeholder>;
+		using position_type = std::uint32_t;
+
+		ValueNode();
+		ValueNode(std::string_view string, position_type position = 0);
+		ValueNode(std::vector<internal_value_type> value_list, position_type position = 0);
+		ValueNode(std::initializer_list<internal_value_type> value_list, position_type position = 0);
+
+		void set_position(position_type position);
+		position_type get_position() const;
+
+		void set_as_list(internal_value_type value);
+		void add_to_list(internal_value_type value);
+		bool list_is_empty() const;
+
+		inline std::string make_from_map(const IsMap<std::string> auto& map) const {
+			std::vector<std::string_view> pre_joined(_value_list.size());
+
+			for (auto&& value : _value_list) {
+				pre_joined.push_back(std::visit([&](auto&& arg) -> std::string_view {
+					using T = std::decay_t<decltype(arg)>;
+					if constexpr (std::is_same_v<T, std::string>) {
+						return arg;
+					} else if constexpr (std::is_same_v<T, Placeholder>) {
+						return map[arg.value];
+					}
+				},
+					value));
+			}
+
+			return fmt::format(FMT_COMPILE("{}"), fmt::join(pre_joined, ""));
+		}
+
+		std::string make(std::string_view prefix = Placeholder::ESCAPE_STR, std::optional<std::string_view> suffix = std::nullopt) const;
+
+	private:
+		position_type _position;
+		std::vector<internal_value_type> _value_list;
+	};
+}
\ No newline at end of file