Rework Grammar and Parser

Properly construct headless binary with basic validation and print functionality

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

Add proper Grammar value retrieval
Simplify AST node resolution for Grammar

Add AbstractSyntaxTree for v2script data parser:
	Has compile-time embedded type information accessible at compile-time and runtime
	Optionally compiled AST print functionality

Add detail/TypeName.hpp
Add detail/SelfType.hpp
Add detail/DetectUtf8.hpp
Add detail/Errors.hpp
Add detail/Warnings.hpp

Add `OPENVIC_DATALOADER_PRINT_NODES` for headless construction
Fix wrong environment reference for headless construction in SConstruct

11 files changed, 528 insertions, 75 deletions

diff --git a/src/headless/main.cpp b/src/headless/main.cpp
index ffc6dab..afd569f 100644
--- a/src/headless/main.cpp
+++ b/src/headless/main.cpp
@@ -1,3 +1,35 @@
-int main() {
+#include <cstdio>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <openvic-dataloader/v2script/Parser.hpp>
+
+int main(int argc, char** argv) {
+	if (argc < 2) {
+		std::fprintf(stderr, "usage: %s <filename>", argv[0]);
+		return 1;
+	}
+
+	auto parser = ovdl::v2script::Parser::from_file(argv[1]);
+	if (parser.has_error()) {
+		return 1;
+	}
+
+	parser.simple_parse();
+	if (parser.has_error()) {
+		return 2;
+	}
+
+	if (parser.has_warning()) {
+		for (auto& warning : parser.get_warnings()) {
+			std::cerr << "Warning: " << warning.message << std::endl;
+		}
+	}
+
+#ifdef OPENVIC_DATALOADER_PRINT_NODES
+	parser.get_file_node()->print(std::cout);
+#endif
+
 	return 0;
 }
\ 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..b2969ce
--- /dev/null
+++ b/src/openvic-dataloader/detail/DetectUtf8.hpp
@@ -0,0 +1,52 @@
+#pragma once
+
+#include "detail/LexyLitRange.hpp"
+#include <lexy/action/match.hpp>
+#include <lexy/dsl.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..f8ed21b
--- /dev/null
+++ b/src/openvic-dataloader/detail/Errors.hpp
@@ -0,0 +1,19 @@
+#pragma once
+
+#include "openvic-dataloader/v2script/Parser.hpp"
+
+namespace ovdl::v2script::errors {
+	inline const v2script::Parser::Error 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 v2script::Parser::Error { Parser::Error::Type::Fatal, message, 1 };
+	}
+}
+
+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/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/Warnings.hpp b/src/openvic-dataloader/detail/Warnings.hpp
new file mode 100644
index 0000000..f854fa8
--- /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 v2script::Parser::Warning 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 v2script::Parser::Warning { message, 1 };
+	}
+}
+
+namespace ovdl::ovscript::warnings {
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/v2script/DecisionGrammar.hpp b/src/openvic-dataloader/v2script/DecisionGrammar.hpp
new file mode 100644
index 0000000..ebc9ad2
--- /dev/null
+++ b/src/openvic-dataloader/v2script/DecisionGrammar.hpp
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <lexy/callback.hpp>
+#include <lexy/dsl.hpp>
+#include <openvic-dataloader/v2script/AbstractSyntaxTree.hpp>
+
+// Decision Grammar Definitions //
+namespace ovdl::v2script::grammar {
+
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/v2script/EventGrammar.hpp b/src/openvic-dataloader/v2script/EventGrammar.hpp
new file mode 100644
index 0000000..7ab40d4
--- /dev/null
+++ b/src/openvic-dataloader/v2script/EventGrammar.hpp
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <lexy/callback.hpp>
+#include <lexy/dsl.hpp>
+#include <openvic-dataloader/v2script/AbstractSyntaxTree.hpp>
+
+// Event Grammar Definitions //
+namespace ovdl::v2script::grammar {
+
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/v2script/Grammar.cpp b/src/openvic-dataloader/v2script/Grammar.cpp
deleted file mode 100644
index ec9fac2..0000000
--- a/src/openvic-dataloader/v2script/Grammar.cpp
+++ /dev/null
@@ -1,74 +0,0 @@
-#include <lexy/dsl.hpp>
-#include <openvic-dataloader/v2script/Parser.hpp>
-
-using namespace ovdl::v2script;
-
-// Node Definitions //
-namespace dsl = lexy::dsl;
-
-namespace ovdl::v2script::nodes {
-	struct StatementListBlock;
-
-	static constexpr auto whitespace_specifier = dsl::code_point.range<0x09, 0x0A>() / dsl::lit_cp<0x0D> / dsl::lit_cp<0x20>;
-	static constexpr auto comment_specifier = LEXY_LIT("#") >> dsl::until(dsl::newline).or_eof();
-
-	static constexpr auto data_specifier =
-		dsl::ascii::alpha_digit_underscore /
-		dsl::code_point.range<0x25, 0x27>() / dsl::lit_cp<0x2B> / dsl::code_point.range<0x2D, 0x2E>() /
-		dsl::lit_cp<0x3A> /
-		dsl::lit_cp<0x8A> / dsl::lit_cp<0x8C> / dsl::lit_cp<0x8E> /
-		dsl::lit_cp<0x92> / dsl::lit_cp<0x9A> / dsl::lit_cp<0x9C> / dsl::code_point.range<0x9E, 0x9F>() /
-		dsl::code_point.range<0xC0, 0xD6>() / dsl::code_point.range<0xD8, 0xF6>() / dsl::code_point.range<0xF8, 0xFF>();
-
-	static constexpr auto data_char_class = LEXY_CHAR_CLASS("DataSpecifier", data_specifier);
-
-	struct Identifier {
-		static constexpr auto rule = dsl::identifier(data_char_class);
-	};
-
-	struct StringExpression {
-		static constexpr auto escaped_symbols = lexy::symbol_table<char> //
-													.map<'"'>('"')
-													.map<'\''>('\'')
-													.map<'\\'>('\\')
-													.map<'/'>('/')
-													.map<'b'>('\b')
-													.map<'f'>('\f')
-													.map<'n'>('\n')
-													.map<'r'>('\r')
-													.map<'t'>('\t');
-		static constexpr auto rule = [] {
-			// Arbitrary code points that aren't control characters.
-			auto c = -dsl::unicode::control;
-
-			// Escape sequences start with a backlash.
-			// They either map one of the symbols,
-			// or a Unicode code point of the form uXXXX.
-			auto escape = dsl::backslash_escape //
-							  .symbol<escaped_symbols>()
-							  .rule(dsl::lit_c<'u'> >> dsl::code_point_id<4>);
-			return dsl::quoted(c, escape);
-		}();
-	};
-
-	struct AssignmentStatement {
-		static constexpr auto rule = dsl::p<Identifier> >>
-									 (dsl::equal_sign >>
-											 (dsl::p<Identifier> | dsl::p<StringExpression> | dsl::recurse_branch<StatementListBlock>) |
-										 dsl::else_ >> dsl::return_);
-	};
-
-	struct StatementListBlock {
-		static constexpr auto rule =
-			dsl::curly_bracketed.open() >>
-			dsl::opt(dsl::list(dsl::p<AssignmentStatement>)) + dsl::opt(dsl::semicolon) +
-				dsl::curly_bracketed.close();
-	};
-
-	struct File {
-		// Allow arbitrary spaces between individual tokens.
-		static constexpr auto whitespace = whitespace_specifier | comment_specifier;
-
-		static constexpr auto rule = dsl::terminator(dsl::eof).list(dsl::p<AssignmentStatement>);
-	};
-}
diff --git a/src/openvic-dataloader/v2script/Parser.cpp b/src/openvic-dataloader/v2script/Parser.cpp
new file mode 100644
index 0000000..c0b6bd8
--- /dev/null
+++ b/src/openvic-dataloader/v2script/Parser.cpp
@@ -0,0 +1,224 @@
+#include "openvic-dataloader/v2script/Parser.hpp"
+
+#include <iostream>
+#include <memory>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include "SimpleGrammar.hpp"
+#include "detail/DetectUtf8.hpp"
+#include "detail/Errors.hpp"
+#include "detail/NullBuff.hpp"
+#include "detail/Warnings.hpp"
+#include <lexy/action/parse.hpp>
+#include <lexy/encoding.hpp>
+#include <lexy/input/buffer.hpp>
+#include <lexy/input/file.hpp>
+#include <lexy/lexeme.hpp>
+#include <lexy/visualize.hpp>
+#include <lexy_ext/report_error.hpp>
+#include <openvic-dataloader/v2script/AbstractSyntaxTree.hpp>
+
+using namespace ovdl::v2script;
+
+///	BufferHandler ///
+
+class Parser::BufferHandler {
+public:
+	bool is_valid() const {
+		return _buffer.size() != 0;
+	}
+
+	std::optional<Error> load_buffer(const char* data, std::size_t size) {
+		_buffer = lexy::buffer(data, size);
+		return std::nullopt;
+	}
+
+	std::optional<Error> load_buffer(const char* start, const char* end) {
+		_buffer = lexy::buffer(start, end);
+		return std::nullopt;
+	}
+
+	std::optional<Error> load_file(const char* path) {
+		auto file = lexy::read_file(path);
+		if (!file) {
+			return errors::make_no_file_error(path);
+		}
+
+		_buffer = file.buffer();
+		return std::nullopt;
+	}
+
+	constexpr bool is_exclusive_utf8() const {
+		return detail::is_utf8_no_ascii(_buffer);
+	}
+
+	template<typename Node, typename ErrorCallback>
+	std::optional<std::vector<Error>> parse(const ErrorCallback& callback) {
+		auto result = lexy::parse<Node>(_buffer, callback);
+		if (!result) {
+			std::vector<Error> errors;
+			return errors;
+		}
+		// This is mighty frustrating
+		_root = std::unique_ptr<ast::Node>(result.value());
+		return std::nullopt;
+	}
+
+	std::unique_ptr<ast::Node>& get_root() {
+		return _root;
+	}
+
+private:
+	lexy::buffer<lexy::default_encoding> _buffer;
+	std::unique_ptr<ast::Node> _root;
+};
+
+/// BufferHandler ///
+
+Parser::Parser()
+	: _buffer_handler(std::make_unique<BufferHandler>()),
+	  _error_stream(detail::cnull) {
+	set_error_log_to_stderr();
+}
+
+Parser::Parser(Parser&&) = default;
+Parser& Parser::operator=(Parser&& value) = default;
+Parser::~Parser() = default;
+
+Parser Parser::from_buffer(const char* data, std::size_t size) {
+	Parser result;
+	return std::move(result.load_from_buffer(data, size));
+}
+
+Parser Parser::from_buffer(const char* start, const char* end) {
+	Parser result;
+	return std::move(result.load_from_buffer(start, end));
+}
+
+Parser Parser::from_file(const char* path) {
+	Parser result;
+	return std::move(result.load_from_file(path));
+}
+
+///
+/// @brief Executes a function on _buffer_handler that is expected to load a buffer
+///
+/// Expected Use:
+/// @code {.cpp}
+///	_run_load_func(&BufferHandler::<load_function>, <arguments>);
+/// @endcode
+///
+/// @tparam Args
+/// @param func
+/// @param args
+///
+template<typename... Args>
+inline void Parser::_run_load_func(std::optional<Error> (BufferHandler::*func)(Args...), Args... args) {
+	_warnings.clear();
+	_errors.clear();
+	_has_fatal_error = false;
+	if (auto error = (_buffer_handler.get()->*func)(args...); error) {
+		_has_fatal_error = error.value().type == Error::Type::Fatal;
+		_errors.push_back(error.value());
+		_error_stream.get() << "Error: " << _errors.back().message << '\n';
+	}
+}
+
+Parser& Parser::load_from_buffer(const char* data, std::size_t size) {
+	_run_load_func(&BufferHandler::load_buffer, data, size);
+	return *this;
+}
+
+Parser& Parser::load_from_buffer(const char* start, const char* end) {
+	_run_load_func(&BufferHandler::load_buffer, start, end);
+	return *this;
+}
+
+Parser& Parser::load_from_file(const char* path) {
+	_file_path = path;
+	_run_load_func(&BufferHandler::load_file, path);
+	return *this;
+}
+
+void Parser::set_error_log_to_null() {
+	set_error_log_to(detail::cnull);
+}
+
+void Parser::set_error_log_to_stderr() {
+	set_error_log_to(std::cerr);
+}
+
+void Parser::set_error_log_to_stdout() {
+	set_error_log_to(std::cout);
+}
+
+void Parser::set_error_log_to(std::basic_ostream<char>& stream) {
+	_error_stream = stream;
+}
+
+bool Parser::simple_parse() {
+	if (!_buffer_handler->is_valid()) {
+		return false;
+	}
+
+	struct ostream_output_iterator {
+		std::reference_wrapper<std::ostream> _stream;
+
+		auto operator*() const noexcept {
+			return *this;
+		}
+		auto operator++(int) const noexcept {
+			return *this;
+		}
+
+		ostream_output_iterator& operator=(char c) {
+			_stream.get().put(c);
+			return *this;
+		}
+	};
+
+	if (_buffer_handler->is_exclusive_utf8()) {
+		_warnings.push_back(warnings::make_utf8_warning(_file_path));
+	}
+
+	auto errors = _buffer_handler->parse<grammar::File>(lexy_ext::report_error.path(_file_path).to(ostream_output_iterator { _error_stream }));
+	if (errors) {
+		_errors.reserve(errors->size());
+		for (auto& err : errors.value()) {
+			_has_fatal_error |= err.type == Error::Type::Fatal;
+			_errors.push_back(err);
+			_error_stream.get() << "Error: " << err.message << '\n';
+		}
+		return false;
+	}
+	_file_node.reset(static_cast<ast::FileNode*>(_buffer_handler->get_root().release()));
+	return true;
+}
+
+bool Parser::has_error() const {
+	return !_errors.empty();
+}
+
+bool Parser::has_fatal_error() const {
+	return _has_fatal_error;
+}
+
+bool Parser::has_warning() const {
+	return !_warnings.empty();
+}
+
+const std::vector<Parser::Error>& Parser::get_errors() const {
+	return _errors;
+}
+
+const std::vector<Parser::Warning>& Parser::get_warnings() const {
+	return _warnings;
+}
+
+const FileNode* Parser::get_file_node() const {
+	return _file_node.get();
+}
\ No newline at end of file
diff --git a/src/openvic-dataloader/v2script/SimpleGrammar.hpp b/src/openvic-dataloader/v2script/SimpleGrammar.hpp
new file mode 100644
index 0000000..48a80ce
--- /dev/null
+++ b/src/openvic-dataloader/v2script/SimpleGrammar.hpp
@@ -0,0 +1,105 @@
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "detail/LexyLitRange.hpp"
+#include <lexy/callback.hpp>
+#include <lexy/dsl.hpp>
+#include <openvic-dataloader/v2script/AbstractSyntaxTree.hpp>
+
+// Grammar Definitions //
+namespace ovdl::v2script::grammar {
+	struct StatementListBlock;
+
+	static constexpr auto whitespace_specifier = lexy::dsl::ascii::blank / lexy::dsl::ascii::newline;
+	static constexpr auto comment_specifier = LEXY_LIT("#") >> lexy::dsl::until(lexy::dsl::newline).or_eof();
+
+	static constexpr auto data_specifier =
+		lexy::dsl::ascii::alpha_digit_underscore /
+		LEXY_ASCII_ONE_OF("%&'") / lexy::dsl::lit_c<0x2B> / LEXY_ASCII_ONE_OF("-.") /
+		lexy::dsl::ascii::digit / lexy::dsl::lit_c<0x3A> /
+		lexy::dsl::lit_c<0x40> / lexy::dsl::ascii::upper / lexy::dsl::lit_c<0x5F> /
+		lexy::dsl::ascii::lower / lexy::dsl::lit_b<0x8A> / lexy::dsl::lit_b<0x8C> / lexy::dsl::lit_b<0x8E> /
+		lexy::dsl::lit_b<0x92> / lexy::dsl::lit_b<0x97> / lexy::dsl::lit_b<0x9A> / lexy::dsl::lit_b<0x9C> / lexy::dsl::lit_b<0x9E> / lexy::dsl::lit_b<0x9F> /
+		lexy::dsl::lit_b<0xC0> /
+		ovdl::detail::lexydsl::make_range<0xC0, 0xD6>() / ovdl::detail::lexydsl::make_range<0xD8, 0xF6>() / ovdl::detail::lexydsl::make_range<0xF8, 0xFF>();
+
+	static constexpr auto data_char_class = LEXY_CHAR_CLASS("DataSpecifier", data_specifier);
+
+	struct Identifier {
+		static constexpr auto rule = lexy::dsl::identifier(data_char_class);
+		static constexpr auto value = lexy::as_string<std::string> | lexy::new_<ast::IdentifierNode, ast::NodePtr>;
+	};
+
+	struct StringExpression {
+		static constexpr auto escaped_symbols = lexy::symbol_table<char> //
+													.map<'"'>('"')
+													.map<'\''>('\'')
+													.map<'\\'>('\\')
+													.map<'/'>('/')
+													.map<'b'>('\b')
+													.map<'f'>('\f')
+													.map<'n'>('\n')
+													.map<'r'>('\r')
+													.map<'t'>('\t');
+		static constexpr auto rule = [] {
+			// Arbitrary code points that aren't control characters.
+			auto c = ovdl::detail::lexydsl::make_range<0x20, 0xFF>() - lexy::dsl::ascii::control;
+
+			// Escape sequences start with a backlash.
+			// They either map one of the symbols,
+			// or a Unicode code point of the form uXXXX.
+			auto escape = lexy::dsl::backslash_escape //
+							  .symbol<escaped_symbols>();
+			return lexy::dsl::quoted(c, escape);
+		}();
+
+		static constexpr auto value = lexy::as_string<std::string> >> lexy::new_<ast::StringNode, ast::NodePtr>;
+	};
+
+	struct AssignmentStatement {
+		static constexpr auto rule =
+			lexy::dsl::p<Identifier> >>
+				(lexy::dsl::equal_sign >>
+						(lexy::dsl::p<Identifier> | lexy::dsl::p<StringExpression> | lexy::dsl::recurse_branch<StatementListBlock>) |
+					lexy::dsl::else_ >> lexy::dsl::return_) |
+			lexy::dsl::p<StringExpression>;
+
+		static constexpr auto value = lexy::callback<ast::NodePtr>(
+			[](auto name, lexy::nullopt = {}) {
+				return LEXY_MOV(name);
+			},
+			[](auto name, auto&& initalizer) {
+				return make_node_ptr<ast::AssignNode>(LEXY_MOV(name), LEXY_MOV(initalizer));
+			});
+	};
+
+	struct StatementListBlock {
+		static constexpr auto rule =
+			lexy::dsl::curly_bracketed.open() >>
+			lexy::dsl::opt(lexy::dsl::list(lexy::dsl::p<AssignmentStatement>)) + lexy::dsl::opt(lexy::dsl::semicolon) +
+				lexy::dsl::curly_bracketed.close();
+
+		static constexpr auto value =
+			lexy::as_list<std::vector<ast::NodePtr>> >>
+			lexy::callback<ast::NodePtr>(
+				[](lexy::nullopt = {}, lexy::nullopt = {}) {
+					return ast::make_node_ptr<ast::ListNode>();
+				},
+				[](auto&& list, lexy::nullopt = {}) {
+					return make_node_ptr<ast::ListNode>(LEXY_MOV(list));
+				},
+				[](auto& list) {
+					return make_node_ptr<ast::ListNode>(list);
+				});
+	};
+
+	struct File {
+		// Allow arbitrary spaces between individual tokens.
+		static constexpr auto whitespace = whitespace_specifier | comment_specifier;
+
+		static constexpr auto rule = lexy::dsl::terminator(lexy::dsl::eof).list(lexy::dsl::p<AssignmentStatement>);
+
+		static constexpr auto value = lexy::as_list<std::vector<ast::NodePtr>> >> lexy::new_<ast::FileNode, ast::NodePtr>;
+	};
+}