Rework Grammar and Parser

Add proper headless binary construction:
	Includes basic validation

Add Error and Warning structs to Parser
Add FileNode pointer getter to Parser
Change all `char8_t*` and `const char8_t` to `const char*` in Parser
Add Parser move operators and Parser deconstructor
Add BufferHandler PIMPL object to Parser
Add UTF-8 file Warning to v2script
Add proper Grammar value retrieval
Add AbstractSyntaxTree for v2script data parser:
	Has compile-time embedded type information accessible at compile-time and runtime
	Has Tab-based print functionality

Fix wrong environment reference for headless construction in SConstruct
Add error retrieval
Add BasicCallbackOStreamBuffer for callback streaming
Add CallbackStreamBuffer for char
Add CallbackWStreamBuffer for wchar_t
Add BasicCallbackStream
Add CallbackStream for char
Add CallbackWStream for wchar_t
Add grammar for events and decisions
Add event_parse to Parser
Add decision_parse to Parser
Add .clang-format
Ignore dirty lexy module
Add CSV parser and grammar:
	Creates std::vector<csv::LineObject> for a list of lines

Add BasicParser and BasicBufferHandler to reduce code reduplication

9 files changed, 357 insertions, 0 deletions

diff --git a/src/openvic-dataloader/detail/BasicBufferHandler.hpp b/src/openvic-dataloader/detail/BasicBufferHandler.hpp
new file mode 100644
index 0000000..ba2cef9
--- /dev/null
+++ b/src/openvic-dataloader/detail/BasicBufferHandler.hpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <optional>
+
+#include <openvic-dataloader/ParseError.hpp>
+
+#include <lexy/encoding.hpp>
+#include <lexy/input/buffer.hpp>
+#include <lexy/input/file.hpp>
+
+#include "detail/Errors.hpp"
+
+namespace ovdl::detail {
+	template<typename Encoding = lexy::default_encoding, typename MemoryResource = void>
+	class BasicBufferHandler {
+	public:
+		constexpr bool is_valid() const {
+			return _buffer.size() != 0;
+		}
+
+		constexpr std::optional<ovdl::ParseError> load_buffer_size(const char* data, std::size_t size) {
+			_buffer = lexy::buffer<Encoding, MemoryResource>(data, size);
+			return std::nullopt;
+		}
+
+		constexpr std::optional<ovdl::ParseError> load_buffer(const char* start, const char* end) {
+			_buffer = lexy::buffer<Encoding, MemoryResource>(start, end);
+			return std::nullopt;
+		}
+
+		std::optional<ovdl::ParseError> load_file(const char* path) {
+			auto file = lexy::read_file<Encoding, lexy::encoding_endianness::bom, MemoryResource>(path);
+			if (!file) {
+				return ovdl::errors::make_no_file_error(path);
+			}
+
+			_buffer = file.buffer();
+			return std::nullopt;
+		}
+
+	protected:
+		lexy::buffer<Encoding, MemoryResource> _buffer;
+	};
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/BasicParser.cpp b/src/openvic-dataloader/detail/BasicParser.cpp
new file mode 100644
index 0000000..ee1b516
--- /dev/null
+++ b/src/openvic-dataloader/detail/BasicParser.cpp
@@ -0,0 +1,47 @@
+#include <iostream>
+#include <ostream>
+
+#include <openvic-dataloader/detail/BasicParser.hpp>
+
+#include "detail/NullBuff.hpp"
+
+using namespace ovdl;
+using namespace ovdl::detail;
+
+BasicParser::BasicParser() : _error_stream(detail::cnull) {}
+
+void BasicParser::set_error_log_to_null() {
+	set_error_log_to(detail::cnull);
+}
+
+void BasicParser::set_error_log_to_stderr() {
+	set_error_log_to(std::cerr);
+}
+
+void BasicParser::set_error_log_to_stdout() {
+	set_error_log_to(std::cout);
+}
+
+void BasicParser::set_error_log_to(std::basic_ostream<char>& stream) {
+	_error_stream = stream;
+}
+
+bool BasicParser::has_error() const {
+	return !_errors.empty();
+}
+
+bool BasicParser::has_fatal_error() const {
+	return _has_fatal_error;
+}
+
+bool BasicParser::has_warning() const {
+	return !_warnings.empty();
+}
+
+const std::vector<ovdl::ParseError>& BasicParser::get_errors() const {
+	return _errors;
+}
+
+const std::vector<ovdl::ParseWarning>& BasicParser::get_warnings() const {
+	return _warnings;
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/DetectUtf8.hpp b/src/openvic-dataloader/detail/DetectUtf8.hpp
new file mode 100644
index 0000000..2045b3c
--- /dev/null
+++ b/src/openvic-dataloader/detail/DetectUtf8.hpp
@@ -0,0 +1,53 @@
+#pragma once
+
+#include <lexy/action/match.hpp>
+#include <lexy/dsl.hpp>
+
+#include "detail/LexyLitRange.hpp"
+
+namespace ovdl::detail {
+	namespace detect_utf8 {
+
+		template<bool INCLUDE_ASCII>
+		struct DetectUtf8 {
+			struct not_utf8 {
+				static constexpr auto name = "not utf8";
+			};
+
+			static constexpr auto rule = [] {
+				constexpr auto is_not_ascii_flag = lexy::dsl::context_flag<DetectUtf8>;
+
+				// & 0b10000000 == 0b00000000
+				constexpr auto ascii_values = lexydsl::make_range<0b00000000, 0b01111111>();
+				// & 0b11100000 == 0b11000000
+				constexpr auto two_byte = lexydsl::make_range<0b11000000, 0b11011111>();
+				// & 0b11110000 == 0b11100000
+				constexpr auto three_byte = lexydsl::make_range<0b11100000, 0b11101111>();
+				// & 0b11111000 == 0b11110000
+				constexpr auto four_byte = lexydsl::make_range<0b11110000, 0b11110111>();
+				// & 0b11000000 == 0b10000000
+				constexpr auto check_bytes = lexydsl::make_range<0b10000000, 0b10111111>();
+
+				constexpr auto utf8_check =
+					((four_byte >> lexy::dsl::times<3>(check_bytes)) |
+						(three_byte >> lexy::dsl::times<2>(check_bytes)) |
+						(two_byte >> lexy::dsl::times<1>(check_bytes))) >>
+					is_not_ascii_flag.set();
+
+				return is_not_ascii_flag.template create<INCLUDE_ASCII>() +
+					   lexy::dsl::while_(utf8_check | ascii_values) +
+					   lexy::dsl::must(is_not_ascii_flag.is_set()).template error<not_utf8>;
+			}();
+		};
+	}
+
+	template<typename Input>
+	constexpr bool is_utf8_no_ascii(const Input& input) {
+		return lexy::match<detect_utf8::DetectUtf8<false>>(input);
+	}
+
+	template<typename Input>
+	constexpr bool is_utf8(const Input& input) {
+		return lexy::match<detect_utf8::DetectUtf8<true>>(input);
+	}
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/Errors.hpp b/src/openvic-dataloader/detail/Errors.hpp
new file mode 100644
index 0000000..f53bedc
--- /dev/null
+++ b/src/openvic-dataloader/detail/Errors.hpp
@@ -0,0 +1,23 @@
+#pragma once
+
+#include "openvic-dataloader/v2script/Parser.hpp"
+
+namespace ovdl::errors {
+	inline const ParseError make_no_file_error(const char* file_path) {
+		std::string message;
+		if (!file_path) {
+			message = "File path not specified.";
+		} else {
+			message = "File '" + std::string(file_path) + "' was not found.";
+		}
+
+		return ParseError { ParseError::Type::Fatal, message, 1 };
+	}
+}
+
+namespace ovdl::v2script::errors {
+
+}
+
+namespace ovdl::ovscript::errors {
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/LexyLitRange.hpp b/src/openvic-dataloader/detail/LexyLitRange.hpp
new file mode 100644
index 0000000..a6761a8
--- /dev/null
+++ b/src/openvic-dataloader/detail/LexyLitRange.hpp
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <lexy/dsl/literal.hpp>
+
+namespace ovdl::detail::lexydsl {
+	template<unsigned char LOW, unsigned char HIGH>
+	consteval auto make_range() {
+		if constexpr (LOW == HIGH) {
+			return lexy::dsl::lit_c<LOW>;
+		} else if constexpr (LOW == (HIGH - 1)) {
+			return lexy::dsl::lit_c<LOW> / lexy::dsl::lit_c<HIGH>;
+		} else {
+			return lexy::dsl::lit_c<LOW> / make_range<LOW + 1, HIGH>();
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/LexyReportError.hpp b/src/openvic-dataloader/detail/LexyReportError.hpp
new file mode 100644
index 0000000..684b5db
--- /dev/null
+++ b/src/openvic-dataloader/detail/LexyReportError.hpp
@@ -0,0 +1,102 @@
+#pragma once
+
+#include <cstddef>
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <openvic-dataloader/ParseData.hpp>
+#include <openvic-dataloader/ParseError.hpp>
+
+#include <lexy/input_location.hpp>
+#include <lexy/visualize.hpp>
+
+#include <lexy_ext/report_error.hpp>
+
+namespace ovdl::detail {
+	template<typename OutputIterator>
+	struct _ReportError {
+		OutputIterator _iter;
+		lexy::visualization_options _opts;
+		const char* _path;
+
+		struct _sink {
+			OutputIterator _iter;
+			lexy::visualization_options _opts;
+			const char* _path;
+			std::size_t _count;
+			std::vector<ParseError> _errors;
+
+			using return_type = std::vector<ParseError>;
+
+			template<typename Input, typename Reader, typename Tag>
+			void operator()(const lexy::error_context<Input>& context, const lexy::error<Reader, Tag>& error) {
+				_iter = lexy_ext::_detail::write_error(_iter, context, error, _opts, _path);
+				++_count;
+
+				// Convert the context location and error location into line/column information.
+				auto context_location = lexy::get_input_location(context.input(), context.position());
+				auto location = lexy::get_input_location(context.input(), error.position(), context_location.anchor());
+
+				std::basic_stringstream<typename Reader::encoding::char_type> message;
+
+				// Write the main annotation.
+				if constexpr (std::is_same_v<Tag, lexy::expected_literal>) {
+					auto string = lexy::_detail::make_literal_lexeme<typename Reader::encoding>(error.string(), error.length());
+
+					message << "expected '" << string.data() << '\'';
+				} else if constexpr (std::is_same_v<Tag, lexy::expected_keyword>) {
+					auto string = lexy::_detail::make_literal_lexeme<typename Reader::encoding>(error.string(), error.length());
+
+					message << "expected keyword '" << string.data() << '\'';
+				} else if constexpr (std::is_same_v<Tag, lexy::expected_char_class>) {
+					message << "expected " << error.name();
+				} else {
+					message << error.message();
+				}
+
+				_errors.push_back(
+					ParseError {
+						ParseError::Type::Fatal, // TODO: distinguish recoverable errors from fatal errors
+						std::move(message.str()),
+						0, // TODO: implement proper error codes
+						ParseData {
+							context.production(),
+							context_location.line_nr(),
+							context_location.column_nr(),
+						},
+						location.line_nr(),
+						location.column_nr(),
+					});
+			}
+
+			return_type finish() && {
+				if (_count != 0)
+					*_iter++ = '\n';
+				return _errors;
+			}
+		};
+		constexpr auto sink() const {
+			return _sink { _iter, _opts, _path, 0 };
+		}
+
+		/// Specifies a path that will be printed alongside the diagnostic.
+		constexpr _ReportError path(const char* path) const {
+			return { _iter, _opts, path };
+		}
+
+		/// Specifies an output iterator where the errors are written to.
+		template<typename OI>
+		constexpr _ReportError<OI> to(OI out) const {
+			return { out, _opts, _path };
+		}
+
+		/// Overrides visualization options.
+		constexpr _ReportError opts(lexy::visualization_options opts) const {
+			return { _iter, opts, _path };
+		}
+	};
+
+	constexpr auto ReporError = _ReportError<lexy::stderr_output_iterator> {};
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/NullBuff.hpp b/src/openvic-dataloader/detail/NullBuff.hpp
new file mode 100644
index 0000000..baf9e1b
--- /dev/null
+++ b/src/openvic-dataloader/detail/NullBuff.hpp
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <ostream>
+
+namespace ovdl::detail {
+	template<class cT, class traits = std::char_traits<cT>>
+	class basic_nullbuf : public std::basic_streambuf<cT, traits> {
+		typename traits::int_type overflow(typename traits::int_type c) {
+			return traits::not_eof(c); // indicate success
+		}
+	};
+
+	template<class cT, class traits = std::char_traits<cT>>
+	class basic_onullstream : public std::basic_ostream<cT, traits> {
+	public:
+		basic_onullstream() : std::basic_ios<cT, traits>(&m_sbuf),
+							  std::basic_ostream<cT, traits>(&m_sbuf) {
+			std::basic_ios<cT, traits>::init(&m_sbuf);
+		}
+
+	private:
+		basic_nullbuf<cT, traits> m_sbuf;
+	};
+
+	typedef basic_onullstream<char> onullstream;
+	typedef basic_onullstream<wchar_t> wonullstream;
+
+	inline onullstream cnull;
+	inline onullstream wcnull;
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/OStreamOutputIterator.hpp b/src/openvic-dataloader/detail/OStreamOutputIterator.hpp
new file mode 100644
index 0000000..81f6c89
--- /dev/null
+++ b/src/openvic-dataloader/detail/OStreamOutputIterator.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <ostream>
+
+namespace ovdl::detail {
+	struct OStreamOutputIterator {
+		std::reference_wrapper<std::ostream> _stream;
+
+		auto operator*() const noexcept {
+			return *this;
+		}
+		auto operator++(int) const noexcept {
+			return *this;
+		}
+
+		OStreamOutputIterator& operator=(char c) {
+			_stream.get().put(c);
+			return *this;
+		}
+	};
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/detail/Warnings.hpp b/src/openvic-dataloader/detail/Warnings.hpp
new file mode 100644
index 0000000..fc0fbed
--- /dev/null
+++ b/src/openvic-dataloader/detail/Warnings.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include "openvic-dataloader/v2script/Parser.hpp"
+
+namespace ovdl::v2script::warnings {
+	inline const ParseWarning make_utf8_warning(const char* file_path) {
+		constexpr std::string_view message_suffix = "This may cause problems. Prefer Windows-1252 encoding.";
+
+		std::string message;
+		if (!file_path) {
+			message = "Buffer is a UTF-8 encoded string. " + std::string(message_suffix);
+		} else {
+			message = "File '" + std::string(file_path) + "' is a UTF-8 encoded file. " + std::string(message_suffix);
+		}
+
+		return ParseWarning { message, 1 };
+	}
+}
+
+namespace ovdl::ovscript::warnings {
+}
\ No newline at end of file