Print test summary

.gitignore

@@ -1,3 +1,5 @@
-/.dub/
-/dub.selections.json
 /build/
+.cache/
+CMakeFiles/
+CMakeCache.txt
+dub.selections.json

CMakeLists.txt

@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 3.21)
+project(Elna)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+set(CMAKE_CXX_STANDARD 17)
+
+add_executable(tester tests/runner.cpp include/elna/tester.hpp)
+target_include_directories(tester PRIVATE include)
+
+add_executable(elnsh shell/main.cpp
+	shell/interactive.cpp include/elna/interactive.hpp
+	shell/history.cpp include/elna/history.hpp
+	shell/state.cpp include/elna/state.hpp
+)
+target_include_directories(elnsh PRIVATE include)
+
+add_library(elna
+	source/lexer.cpp include/elna/lexer.hpp
+	source/result.cpp include/elna/result.hpp
+	source/riscv.cpp include/elna/riscv.hpp
+	source/ir.cpp include/elna/ir.hpp
+	include/elna/parser.hpp
+)
+target_include_directories(elna PRIVATE include)

Rakefile

@@ -4,66 +4,16 @@ require 'open3'
 
 DFLAGS = ['--warn-no-deprecated', '-L/usr/lib64/gcc-12']
 BINARY = 'build/bin/elna'
-TESTS = FileList['tests/*.elna']
-  .map { |test| (Pathname.new('build') + test).sub_ext('').to_path }
 SOURCES = FileList['source/**/*.d']
 
-directory 'build'
+directory 'build/riscv'
 
 CLEAN.include 'build'
 CLEAN.include '.dub'
 
-rule(/build\/tests\/.+/ => ->(file) { test_for_out(file) }) do |t|
-  Pathname.new(t.name).dirname.mkpath
-  sh BINARY, t.source
-  sh 'gcc', '-o', t.name, "#{t.name}.o"
-  # Open3.pipeline [BINARY, t.source], ['gcc', '-x', 'assembler', '-o', t.name,  '-']
-end
-
 file BINARY => SOURCES do |t|
-  sh({ 'DFLAGS' => (DFLAGS * ' ') }, 'dub', 'build', '--compiler=gdc-12')
+  sh({ 'DFLAGS' => (DFLAGS * ' ') }, 'dub', 'build', '--compiler=gdc')
-end
-
-file 'build/tests/sample' => BINARY do |t|
-  sh t.source
-  sh 'gcc', '-o', t.name, 'build/tests/sample.o'
 end
 
+task default: 'build/riscv'
 task default: BINARY
-
-desc 'Run all tests and check the results'
-task test: TESTS
-task test: BINARY do
-  TESTS.each do |test|
-    expected = Pathname
-      .new(test)
-      .sub_ext('.txt')
-      .sub(/^build\/tests\//, 'tests/expectations/')
-      .read
-      .to_i
-
-    puts "Running #{test}"
-    system test
-    actual = $?.exitstatus
-
-    fail "#{test}: Expected #{expected}, got #{actual}" unless expected == actual
-  end
-
-  # system './build/tests/sample'
-  # actual = $?.exitstatus
-  # fail "./build/tests/sample: Expected 3, got #{actual}" unless 3 == actual
-end
-
-desc 'Run unittest blocks'
-task unittest: SOURCES do |t|
-  sh('dub', 'test', '--compiler=gdc-12')
-end
-
-def test_for_out(out_file)
-  test_source = Pathname
-    .new(out_file)
-    .sub_ext('.elna')
-    .sub(/^build\//, '')
-    .to_path
-  [test_source, BINARY]
-end

TODO

@@ -0,0 +1,23 @@
+# Completion
+
+- Configure fzf to show only the current directory files
+- Support multiple selections for insertion in fzf.
+- Don't hardcode fzf binary path.
+- Send the word under the cursor to fzf as initial input.
+- Home directory expansion.
+- Show files in the PATH if starting at the beginning of the prompt
+
+# Appearance
+
+- Add a bar with additional information under the prompt (edit_bar), like the hostname.
+- Show current time in the prompt.
+
+# Input
+
+- DEL handling.
+- Starting long running process and killing it with Ctrl-C kills the shell.
+
+# Other
+
+- Persist the history.
+- Replace hard coded ANSI codes with constants or functions.

dub.json

@@ -1,9 +1,11 @@
 {
 	"dependencies": {
-		"tanya": "~>0.18.0"
+		"tanya": "~>0.19.0"
 	},
 	"name": "elna",
 	"targetType": "executable",
 	"targetPath": "build/bin",
-	"mainSourceFile": "source/main.d"
+	"mainSourceFile": "source/main.d",
+	"libs": ["elna", "stdc++"],
+	"lflags": ["-Lbuild"]
 }

include/elna/history.hpp

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <boost/core/noncopyable.hpp>
+#include <string>
+#include <list>
+
+namespace elna
+{
+    struct editor_history : public boost::noncopyable
+    {
+        using const_iterator = std::list<std::string>::const_iterator;
+
+        editor_history();
+
+        void push(const std::string& entry);
+        void clear();
+
+        const_iterator next() noexcept;
+        const_iterator prev() noexcept;
+        const_iterator cbegin() const noexcept;
+        const_iterator cend() const noexcept;
+        const_iterator current() const noexcept;
+
+    private:
+        std::list<std::string> commands;
+        std::list<std::string>::const_iterator current_pointer;
+    };
+}

include/elna/interactive.hpp

@@ -0,0 +1,89 @@
+#pragma once
+
+#include <boost/core/noncopyable.hpp>
+#include <stdexcept>
+#include <string>
+#include <optional>
+
+#include "elna/state.hpp"
+#include "elna/history.hpp"
+
+#define BOOST_PROCESS_USE_STD_FS
+
+namespace elna
+{
+    /**
+     * Runtime exception for non recoverable errors.
+     */
+    struct interactive_exception : public std::runtime_error
+    {
+        /**
+         * Constructor.
+         */
+        interactive_exception();
+    };
+
+    /**
+     * Main loop.
+     */
+    void loop();
+
+    /**
+     * Reads the next line.
+     * Returns no value upon receiving end of file.
+     *
+     * \param history Shell history.
+     * \return The read line.
+     */
+    std::optional<editor_state> read_line(editor_history& history);
+
+    /**
+     * Runs a built-in or a command.
+     *
+     * \param line The command and arguments.
+     * \return Whether the input shoud continued (no exit requested).
+     */
+    bool execute(const std::string& line);
+
+    /**
+     * Runs the binary specified in its argument.
+     *
+     * \param program Program name in PATH.
+     */
+    void launch(const std::string& program);
+
+    /**
+     * Enables the raw mode.
+     *
+     * \return Whether the operation was successful.
+     */
+    bool enable_raw_mode();
+
+    /**
+     * Disables the raw mode.
+     */
+    void disable_raw_mode();
+
+    /**
+     * Reads a key.
+     *
+     * \return Read character.
+     */
+    key read_key();
+
+    /**
+     * Calls autocompletion.
+     *
+     * \param User input.
+     * \param Cursor position in the user input.
+     * \return Selected item.
+     */
+    std::string complete(const std::string& input, const std::size_t position);
+
+    /**
+     * Prints the message from the exception.
+     *
+     * \param exception The exception to print.
+     */
+    void print_exception(const std::exception& exception);
+}

include/elna/ir.hpp

@@ -0,0 +1,95 @@
+#pragma once
+
+#include "elna/parser.hpp"
+#include <cstddef>
+#include <cstdint>
+
+namespace elna::ir
+{
+    class Node;
+    class Definition;
+    class Operand;
+    class BinaryExpression;
+    class Variable;
+    class VariableDeclaration;
+    class Number;
+
+    struct IRVisitor
+    {
+        virtual void visit(Node *) = 0;
+        virtual void visit(Definition *) = 0;
+        virtual void visit(Operand *) = 0;
+        virtual void visit(BinaryExpression *) = 0;
+        virtual void visit(Variable *) = 0;
+        virtual void visit(Number *) = 0;
+    };
+
+    /**
+     * AST node.
+     */
+    class Node
+    {
+    public:
+        virtual void accept(IRVisitor *) = 0;
+    };
+
+    /**
+     * Definition.
+     */
+    class Definition : public Node
+    {
+    public:
+        BinaryExpression **statements;
+        std::size_t statementsLength;
+        Operand *result;
+
+        virtual void accept(IRVisitor *visitor) override;
+    };
+
+    class Statement : public Node
+    {
+    };
+
+    class Operand : public Node
+    {
+    public:
+        virtual void accept(IRVisitor *visitor) override;
+    };
+
+    class Number : public Operand
+    {
+    public:
+        std::int32_t value;
+
+        virtual void accept(IRVisitor *visitor) override;
+    };
+
+    class Variable : public Operand
+    {
+    public:
+        std::size_t counter;
+
+        virtual void accept(IRVisitor *visitor) override;
+    };
+
+    class BinaryExpression : public Statement
+    {
+    public:
+        Operand *lhs, *rhs;
+        BinaryOperator _operator;
+
+        BinaryExpression(Operand *lhs, Operand *rhs, BinaryOperator _operator);
+
+        virtual void accept(IRVisitor *visitor) override;
+    };
+
+    class BangExpression : public Statement
+    {
+        Operand *operand;
+
+    public:
+        BangExpression(Operand *operand);
+
+        virtual void accept(IRVisitor *visitor) override;
+    };
+}

include/elna/lexer.hpp

@@ -0,0 +1,109 @@
+#pragma once
+
+#include <string>
+
+#include "elna/result.hpp"
+
+namespace elna
+{
+    /**
+     * Range over the source text that keeps track of the current position.
+     */
+    struct source
+    {
+        class const_iterator
+        {
+            std::string::const_iterator m_buffer;
+            Position m_position;
+
+            const_iterator(std::string::const_iterator buffer,
+                    const Position position = Position());
+
+        public:
+            using iterator_category = std::forward_iterator_tag;
+            using difference_type = ptrdiff_t;
+            using value_type = char;
+            using pointer = const value_type *;
+            using reference = const value_type&;
+
+            const Position& position() const noexcept;
+
+            reference operator*() const noexcept;
+            pointer operator->() const noexcept;
+            const_iterator& operator++();
+            const_iterator& operator++(int);
+            bool operator==(const const_iterator& that) const noexcept;
+            bool operator!=(const const_iterator& that) const noexcept;
+
+            friend source;
+        };
+
+        source(const std::string& buffer);
+        const_iterator begin() const;
+        const_iterator end() const;
+
+    private:
+        const std::string m_buffer;
+    };
+
+    /**
+     * Union type representing a single token.
+     */
+    struct Token
+    {
+        /**
+         * Token type.
+         */
+        enum Type : std::uint16_t
+        {
+            TOKEN_NUMBER = 0,
+            TOKEN_OPERATOR = 1,
+            TOKEN_LET = 2,
+            TOKEN_IDENTIFIER = 3,
+            TOKEN_EQUALS = 4,
+            TOKEN_VAR = 5,
+            TOKEN_SEMICOLON = 6,
+            TOKEN_LEFT_PAREN = 7,
+            TOKEN_RIGHT_PAREN = 8,
+            TOKEN_BANG = 9,
+            TOKEN_DOT = 10,
+            TOKEN_COMMA = 11,
+        };
+
+        /**
+         * Type of the token value.
+         */
+        union Value
+        {
+            std::int32_t number;
+            const char *identifier;
+        };
+
+        Token(Type of, Position position);
+        Token(Type of, std::int32_t value, Position position);
+        Token(Type of, const char *value, Position position);
+        Token(const Token& that);
+        Token(Token&& that);
+        ~Token();
+
+        Token& operator=(const Token& that);
+        Token& operator=(Token&& that);
+
+        Type of() const noexcept;
+        const char *identifier() const noexcept;
+        std::int32_t number() const noexcept;
+        const Position& position() const noexcept;
+
+    private:
+        Type m_type;
+        Value m_value;
+        Position m_position;
+    };
+
+    /**
+     * Split the source into tokens.
+     *
+     * \return Tokens or error.
+     */
+    Token *lex(const char *buffer, CompileError *compile_error, std::size_t *length);
+}

include/elna/parser.hpp

@@ -0,0 +1,10 @@
+#pragma once
+
+namespace elna
+{
+    enum class BinaryOperator
+    {
+        sum,
+        subtraction
+    };
+}

include/elna/result.hpp

@@ -0,0 +1,62 @@
+#pragma once
+
+#include <cstddef>
+#include <boost/outcome.hpp>
+
+namespace elna
+{
+    /**
+     * Position in the source text.
+     */
+    struct Position
+    {
+        /// Line.
+        std::size_t line = 1;
+
+        /// Column.
+        std::size_t column = 1;
+    };
+
+    /**
+     * A compilation error consists of an error message and position.
+     */
+    struct CompileError
+    {
+    private:
+        char const *message;
+        Position position;
+
+    public:
+        /**
+         * @param message Error text.
+         * @param position Error position in the source text.
+         */
+        CompileError(char const *message, const Position position) noexcept;
+
+        /// Error text.
+        const char *what() const noexcept;
+
+        /// Error line in the source text.
+        std::size_t line() const noexcept;
+
+        /// Error column in the source text.
+        std::size_t column() const noexcept;
+    };
+
+    template<typename T>
+    using result = boost::outcome_v2::result<T, CompileError>;
+
+    enum class Target
+    {
+        text,
+        high20,
+        lower12i
+    };
+
+    struct Reference
+    {
+        const char* name;
+        size_t offset;
+        Target target;
+    };
+}

include/elna/riscv.hpp

@@ -0,0 +1,148 @@
+#pragma once
+
+#include <cstdint>
+#include "elna/ir.hpp"
+#include "elna/result.hpp"
+
+namespace elna
+{
+    enum class XRegister : std::uint8_t
+    {
+        zero = 0,
+        ra = 1,
+        sp = 2,
+        gp = 3,
+        tp = 4,
+        t0 = 5,
+        t1 = 6,
+        t2 = 7,
+        s0 = 8,
+        s1 = 9,
+        a0 = 10,
+        a1 = 11,
+        a2 = 12,
+        a3 = 13,
+        a4 = 14,
+        a5 = 15,
+        a6 = 16,
+        a7 = 17,
+        s2 = 18,
+        s3 = 19,
+        s4 = 20,
+        s5 = 21,
+        s6 = 22,
+        s7 = 23,
+        s8 = 24,
+        s9 = 25,
+        s10 = 26,
+        s11 = 27,
+        t3 = 28,
+        t4 = 29,
+        t5 = 30,
+        t6 = 31,
+    };
+
+    enum class Funct3 : std::uint8_t
+    {
+        addi = 0b000,
+        slti = 0b001,
+        sltiu = 0b011,
+        andi = 0b111,
+        ori = 0b110,
+        xori = 0b100,
+        slli = 0b000,
+        srli = 0b101,
+        srai = 0b101,
+        add = 0b000,
+        slt = 0b010,
+        sltu = 0b011,
+        _and = 0b111,
+        _or = 0b110,
+        _xor = 0b100,
+        sll = 0b001,
+        srl = 0b101,
+        sub = 0b000,
+        sra = 0b101,
+        beq = 0b000,
+        bne = 0b001,
+        blt = 0b100,
+        bltu = 0b110,
+        bge = 0b101,
+        bgeu = 0b111,
+        fence = 0b000,
+        fenceI = 0b001,
+        csrrw = 0b001,
+        csrrs = 0b010,
+        csrrc = 0b011,
+        csrrwi = 0b101,
+        csrrsi = 0b110,
+        csrrci = 0b111,
+        priv = 0b000,
+        sb = 0b000,
+        sh = 0b001,
+        sw = 0b010,
+        lb = 0b000,
+        lh = 0b001,
+        lw = 0b010,
+        lbu = 0b100,
+        lhu = 0b101,
+        jalr = 0b000,
+    };
+
+    enum class Funct12 : std::uint8_t
+    {
+        ecall = 0b000000000000,
+        ebreak = 0b000000000001,
+    };
+
+    enum class Funct7 : std::uint8_t
+    {
+        none = 0,
+        sub = 0b0100000
+    };
+
+    enum class BaseOpcode : std::uint8_t
+    {
+        opImm = 0b0010011,
+        lui = 0b0110111,
+        auipc = 0b0010111,
+        op = 0b0110011,
+        jal = 0b1101111,
+        jalr = 0b1100111,
+        branch = 0b1100011,
+        load = 0b0000011,
+        store = 0b0100011,
+        miscMem = 0b0001111,
+        system = 0b1110011,
+    };
+
+    struct Instruction
+    {
+        Instruction(BaseOpcode opcode);
+
+        Instruction& i(XRegister rd, Funct3 funct3, XRegister rs1, std::uint32_t immediate);
+        Instruction& s(std::uint32_t imm1, Funct3 funct3, XRegister rs1, XRegister rs2);
+        Instruction& r(XRegister rd, Funct3 funct3, XRegister rs1, XRegister rs2, Funct7 funct7 = Funct7::none);
+        Instruction& u(XRegister rd, std::uint32_t imm);
+        std::uint8_t *encode();
+
+    private:
+        std::uint32_t instruction{ 0 };
+    };
+
+    class RiscVVisitor : public ir::IRVisitor
+    {
+        Instruction *instructions;
+        std::size_t instructionsLength;
+        bool registerInUse;
+        std::uint32_t variableCounter = 1;
+        Reference references[3];
+
+        virtual void visit(ir::Node *) override;
+        virtual void visit(ir::Definition *definition) override;
+        virtual void visit(ir::Operand *operand) override;
+        virtual void visit(ir::Variable *variable) override;
+        virtual void visit(ir::Number *number) override;
+        virtual void visit(ir::BinaryExpression *expression) override;
+    };
+}

include/elna/state.hpp

@@ -0,0 +1,170 @@
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <variant>
+
+namespace elna
+{
+    constexpr const char *erase_line = "\x1b[2K";
+    constexpr const char *start_kitty_keybaord = "\x1b[>1u";
+    constexpr const char *end_kitty_keybaord = "\x1b[<u";
+
+    std::string cursor_to_column(const std::uint16_t position = 1);
+
+    enum class special_key
+    {
+        arrow_left,
+        arrow_right,
+        arrow_up,
+        arrow_down,
+        page_up,
+        page_down,
+        home_key,
+        end_key,
+    };
+
+    /**
+     * Key modifiers.
+     */
+    enum class modifier : std::uint8_t
+    {
+        shift = 0b1, ///< 1
+        alt = 0b10, ///< 2
+        ctrl = 0b100, ///< 4
+        super = 0b1000, ///< 8
+        hyper = 0b10000, ///< 16
+        meta = 0b100000, ///< 32
+        caps_lock = 0b1000000, ///< 64
+        num_lock = 0b10000000, ///< 128
+    };
+
+    struct key
+    {
+        using char_t = std::uint32_t;
+
+        key();
+        explicit key(const char_t c, const std::uint8_t modifiers = 0);
+        explicit key(const char_t c, const modifier modifiers);
+        explicit key(const special_key control, const std::uint8_t modifiers = 0);
+        explicit key(const special_key control, const modifier modifiers);
+
+        bool operator==(const char_t c) const;
+        friend bool operator==(const char_t c, const key& that);
+        bool operator==(const special_key control) const;
+        friend bool operator==(const special_key control, const key& that);
+        bool operator==(const key& that) const;
+        bool operator!=(const char_t c) const;
+        friend bool operator!=(const char_t c, const key& that);
+        bool operator!=(const special_key control) const;
+        friend bool operator!=(const special_key control, const key& that);
+        bool operator!=(const key& that) const;
+
+        char_t character() const;
+        special_key control() const;
+        bool modified(const std::uint8_t modifiers) const noexcept;
+        bool modified(const modifier modifiers) const noexcept;
+
+        bool is_character() const noexcept;
+        bool is_control() const noexcept;
+        bool empty() const noexcept;
+
+    private:
+        std::variant<special_key, char_t> store;
+        std::uint8_t modifiers;
+    };
+
+    /**
+     * The action should be performed after updating the editor state.
+     */
+    enum class action
+    {
+        redraw, ///< Redraw everything.
+        write, ///< Write a single character.
+        finalize, ///< Finalize command input.
+        move, ///< Move the cursor.
+        ignore, ///< Do nothing.
+        complete, ///< Complete the input.
+        history, ///< Navigate the history.
+    };
+
+    /**
+     * The line editor with its state.
+     */
+    class editor_state
+    {
+        std::string input;
+        std::string prompt = "> ";
+        std::size_t position{ 1 };
+
+    public:
+        editor_state();
+
+        /**
+         * Returns the current input gathered by the lin editor.
+         *
+         * \return User input.
+         */
+        const std::string& command_line() const noexcept;
+
+        /**
+         * Processes the next keypress by changing the line editor state.
+         *
+         * \param key Pressed key.
+         * \return Action to do after the key was pressed.
+         */
+        action process_keypress(const key& press);
+
+        /**
+         * Clears editors working area and writes drawing sequences into the
+         * buffer.
+         *
+         * \param T Output range for bytes.
+         * \param output Output buffer.
+         */
+        template<typename T>
+        void draw(T output) const
+        {
+            std::string code;
+
+            std::copy(erase_line, erase_line + strlen(erase_line), output);
+
+            code = cursor_to_column();
+            std::copy(std::cbegin(code), std::cend(code), output);
+
+            std::copy(std::cbegin(this->prompt), std::cend(this->prompt), output);
+            std::copy(std::cbegin(this->input), std::cend(this->input), output);
+
+            code = cursor_to_column(absolute_position());
+            std::copy(std::cbegin(code), std::cend(code), output);
+        }
+
+        /**
+         * Computes the position in the terminal line.
+         *
+         * \return Position in the terminal line.
+         */
+        std::size_t absolute_position() const noexcept;
+
+        /**
+         * Cursor position relative to the start of the user input.
+         *
+         * \returns Cursor position.
+         */
+        std::size_t relative_position() const noexcept;
+
+        /**
+         * Inserts text at cursor position.
+         *
+         * \param text Text to insert.
+         */
+        void insert(const std::string& text);
+        void insert(const key::char_t text);
+
+        /**
+         * Replaces the user input with the given string.
+         *
+         * \param text New user input string.
+         */
+        void load(const std::string& text);
+    };
+}

include/elna/tester.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <cstdint>
+
+namespace elna
+{
+    class test_results final
+    {
+        std::uint32_t m_total{ 0 };
+        std::uint32_t m_passed{ 0 };
+
+    public:
+        test_results() = default;
+
+        std::uint32_t total() const noexcept;
+        std::uint32_t passed() const noexcept;
+        std::uint32_t failed() const noexcept;
+
+        int exit_code() const noexcept;
+        void add_exit_code(const int exit_code) noexcept;
+    };
+}

shell/history.cpp

@@ -0,0 +1,54 @@
+#include "elna/history.hpp"
+
+namespace elna
+{
+    editor_history::editor_history()
+        : commands{}, current_pointer(commands.cend())
+    {
+    }
+
+    void editor_history::push(const std::string& entry)
+    {
+        commands.push_back(entry);
+        current_pointer = commands.cend();
+    }
+
+    void editor_history::clear()
+    {
+        commands.clear();
+        current_pointer = commands.cend();
+    }
+
+    editor_history::const_iterator editor_history::prev() noexcept
+    {
+        if (this->current_pointer != cbegin())
+        {
+            this->current_pointer = std::prev(this->current_pointer);
+        }
+        return this->current_pointer;
+    }
+
+    editor_history::const_iterator editor_history::next() noexcept
+    {
+        if (this->current_pointer != cend())
+        {
+            this->current_pointer = std::next(this->current_pointer);
+        }
+        return this->current_pointer;
+    }
+
+    editor_history::const_iterator editor_history::cbegin() const noexcept
+    {
+        return this->commands.cbegin();
+    }
+
+    editor_history::const_iterator editor_history::cend() const noexcept
+    {
+        return this->commands.cend();
+    }
+
+    editor_history::const_iterator editor_history::current() const noexcept
+    {
+        return this->current_pointer;
+    }
+}

shell/interactive.cpp

@@ -0,0 +1,286 @@
+#include "elna/interactive.hpp"
+
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/process.hpp>
+#include <termios.h>
+#include <filesystem>
+
+namespace elna
+{
+    static termios original_termios;
+
+    interactive_exception::interactive_exception()
+        : runtime_error("read")
+    {
+    }
+
+    template<typename T>
+    static std::pair<T, unsigned char> read_number()
+    {
+        T position{ 0 };
+        unsigned char c{ 0 };
+
+        while (read(STDIN_FILENO, &c, 1) == 1 && std::isdigit(c))
+        {
+            position = position * 10 + (c - '0');
+        }
+        return std::make_pair(position, c);
+    }
+
+    void loop()
+    {
+        editor_history history;
+        do
+        {
+            auto line = read_line(history);
+
+            if (!line.has_value())
+            {
+                write(STDOUT_FILENO, "\r\n", 2);
+                break;
+            }
+            history.push(line.value().command_line());
+
+            if (!execute(line.value().command_line()))
+            {
+                break;
+            }
+        }
+        while (true);
+    }
+
+    std::optional<editor_state> read_line(editor_history& history)
+    {
+        editor_state state;
+        std::string buffer;
+        std::string saved;
+
+        state.draw(std::back_inserter(buffer));
+        write(STDOUT_FILENO, buffer.data(), buffer.size());
+
+        while (true)
+        {
+            buffer.clear();
+            auto pressed_key = read_key();
+
+            if (pressed_key.empty())
+            {
+                continue;
+            }
+            switch (state.process_keypress(pressed_key))
+            {
+                case action::finalize:
+                    if (pressed_key == key('d', modifier::ctrl))
+                    {
+                        return std::optional<editor_state>();
+                    }
+                    else if (pressed_key == '\r')
+                    {
+                        write(STDOUT_FILENO, "\r\n", 2);
+                        return std::make_optional(state);
+                    }
+                    break;
+                case action::complete:
+                    write(STDOUT_FILENO, "\x1b[1E\x1b[2K", 8);
+                    state.insert(complete(state.command_line(), state.relative_position()));
+                    write(STDOUT_FILENO, "\x1b[1A", 4);
+                    state.draw(std::back_inserter(buffer));
+                    write(STDOUT_FILENO, buffer.data(), buffer.size());
+                    break;
+                case action::redraw:
+                    state.draw(std::back_inserter(buffer));
+                    write(STDOUT_FILENO, buffer.data(), buffer.size());
+                    break;
+                case action::write:
+                    write(STDOUT_FILENO, &pressed_key, 1);
+                    break;
+                case action::move:
+                    buffer = cursor_to_column(state.absolute_position());
+                    write(STDOUT_FILENO, buffer.data(), buffer.size());
+                    break;
+                case action::ignore:
+                    break;
+                case action::history:
+                    editor_history::const_iterator history_iterator = history.cend();
+
+                    if (pressed_key == key(special_key::arrow_up, modifier::ctrl))
+                    {
+                        if (history.current() == history.cend())
+                        {
+                            saved = state.command_line();
+                        }
+                        history_iterator = history.prev();
+                    }
+                    else if (pressed_key == key(special_key::arrow_down, modifier::ctrl))
+                    {
+                        history_iterator = history.next();
+                        if (history_iterator == history.cend())
+                        {
+                            state.load(saved);
+                        }
+                    }
+                    if (history_iterator != history.cend())
+                    {
+                        state.load(*history_iterator);
+                    }
+                    state.draw(std::back_inserter(buffer));
+                    write(STDOUT_FILENO, buffer.data(), buffer.size());
+                    break;
+            }
+        }
+    }
+
+    key read_key()
+    {
+        char c{ 0 };
+
+        if (read(STDIN_FILENO, &c, 1) == -1 && errno != EAGAIN)
+        {
+            throw interactive_exception();
+        }
+        if (c != '\x1b')
+        {
+            return key(c);
+        }
+        if (read(STDIN_FILENO, &c, 1) != 1 || c != '[')
+        {
+            return key();
+        }
+        auto [number, last_char] = read_number<key::char_t>();
+        std::uint8_t modifiers{ 0 };
+
+        if (last_char == ';')
+        {
+            auto modifier_response = read_number<std::uint8_t>();
+            modifiers = modifier_response.first;
+            last_char = modifier_response.second;
+        }
+        if (number == 0 || number == 1)
+        {
+            switch (last_char)
+            {
+                case 'A':
+                    return key(special_key::arrow_up, modifiers);
+                case 'B':
+                    return key(special_key::arrow_down, modifiers);
+                case 'C':
+                    return key(special_key::arrow_right, modifiers);
+                case 'D':
+                    return key(special_key::arrow_left, modifiers);
+                case 'H':
+                    return key(special_key::home_key, modifiers);
+                case 'F':
+                    return key(special_key::end_key, modifiers);
+            }
+        }
+        else if (last_char == '~')
+        {
+            switch (number)
+            {
+                case 5:
+                    return key(special_key::page_up, modifiers);
+                case 6:
+                    return key(special_key::page_up, modifiers);
+                case 7:
+                    return key(special_key::home_key, modifiers);
+                case 8:
+                    return key(special_key::end_key, modifiers);
+            }
+        }
+        else if (last_char == 'u')
+        {
+            return key(number, modifiers);
+        }
+        return key();
+    }
+
+    void print_exception(const std::exception& exception)
+    {
+        std::string message{ exception.what()  };
+        message += "\r\n";
+        write(STDERR_FILENO, message.data(), message.size());
+    }
+
+    bool execute(const std::string& line)
+    {
+        if (line.empty())
+        {
+            return true;
+        }
+        if (line == "exit")
+        {
+            return false;
+        }
+        else if (boost::starts_with(line, "cd "))
+        {
+            try
+            {
+                std::filesystem::current_path(line.substr(strlen("cd ")));
+            }
+            catch (const std::filesystem::filesystem_error& exception)
+            {
+                print_exception(exception);
+            }
+
+            return true;
+        }
+        launch(line);
+        return true;
+    }
+
+    void launch(const std::string& program)
+    {
+        try
+        {
+            boost::process::system(program);
+        }
+        catch (const boost::process::process_error& exception)
+        {
+            print_exception(exception);
+        }
+        enable_raw_mode();
+    }
+
+    bool enable_raw_mode()
+    {
+        if (tcgetattr(STDIN_FILENO, &original_termios) == -1)
+        {
+            return false;
+        }
+        termios raw = original_termios;
+
+        raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+        raw.c_oflag &= ~(OPOST);
+        raw.c_cflag |= CS8;
+        raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+
+        write(STDOUT_FILENO, start_kitty_keybaord, strlen(start_kitty_keybaord));
+
+        return tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) != -1;
+    }
+
+    void disable_raw_mode()
+    {
+        write(STDOUT_FILENO, end_kitty_keybaord, strlen(end_kitty_keybaord));
+        tcsetattr(STDIN_FILENO, TCSAFLUSH, &original_termios);
+    }
+
+    std::string complete(const std::string& input, const std::size_t position)
+    {
+        std::filesystem::path program = boost::process::search_path("fzf");
+
+        if (program.empty())
+        {
+            return "";
+        }
+        boost::process::ipstream output;
+        boost::process::system(program,
+                "--height=10", "--layout=reverse", "-1", "--no-multi",
+                boost::process::std_out > output);
+
+        std::string selections;
+        std::getline(output, selections, '\n');
+
+        return selections;
+    }
+}

shell/main.cpp

@@ -0,0 +1,16 @@
+#include <cstdlib>
+#include <unistd.h>
+#include "elna/interactive.hpp"
+
+int main()
+{
+    if (!elna::enable_raw_mode())
+    {
+        std::perror("tcsetattr");
+        return EXIT_FAILURE;
+    }
+    std::atexit(elna::disable_raw_mode);
+    elna::loop();
+
+    return EXIT_SUCCESS;
+}

shell/state.cpp

@@ -0,0 +1,254 @@
+#include <algorithm>
+#include <boost/endian.hpp>
+
+#include "elna/state.hpp"
+
+namespace elna
+{
+    std::string cursor_to_column(const std::uint16_t position)
+    {
+        std::string code = std::to_string(position);
+        code.insert(0, "\x1b[");
+        code.push_back('G');
+
+        return code;
+    }
+
+    key::key()
+        : store(0x1bu)
+    {
+    }
+
+    key::key(const char_t c, const std::uint8_t modifiers)
+        : store(c), modifiers(modifiers == 0 ? 0 : modifiers - 1)
+    {
+    }
+
+    key::key(const char_t c, const modifier modifiers)
+        : store(c), modifiers(static_cast<uint8_t>(modifiers))
+    {
+    }
+
+    key::key(const special_key control, const std::uint8_t modifiers)
+        : store(control), modifiers(modifiers == 0 ? 0 : modifiers - 1)
+    {
+    }
+
+    key::key(const special_key control, const modifier modifiers)
+        : store(control), modifiers(static_cast<uint8_t>(modifiers))
+    {
+    }
+
+    key::char_t key::character() const
+    {
+        return std::get<char_t>(this->store);
+    }
+
+    special_key key::control() const
+    {
+        return std::get<special_key>(this->store);
+    }
+
+    bool key::modified(const std::uint8_t modifiers) const noexcept
+    {
+        return this->modifiers == modifiers;
+    }
+
+    bool key::modified(const modifier modifiers) const noexcept
+    {
+        return this->modifiers == static_cast<std::uint8_t>(modifiers);
+    }
+
+    bool key::operator==(const char_t c) const
+    {
+        return std::holds_alternative<char_t>(this->store)
+            && std::get<char_t>(this->store) == c;
+    }
+
+    bool key::operator==(const special_key control) const
+    {
+        return std::holds_alternative<special_key>(this->store)
+            && std::get<special_key>(this->store) == control;
+    }
+
+    bool key::operator==(const key& that) const
+    {
+        return this->store == that.store;
+    }
+
+    bool key::operator!=(const char_t c) const
+    {
+        return !(*this == c);
+    }
+
+    bool key::operator!=(const special_key control) const
+    {
+        return !(*this == control);
+    }
+
+    bool key::operator!=(const key& that) const
+    {
+        return !(*this == that);
+    }
+
+    bool key::is_character() const noexcept
+    {
+        return std::holds_alternative<char_t>(this->store);
+    }
+
+    bool key::is_control() const noexcept
+    {
+        return std::holds_alternative<special_key>(this->store);
+    }
+
+    bool key::empty() const noexcept
+    {
+        return *this == '\x1b';
+    }
+
+    bool operator==(const special_key control, const key& that)
+    {
+        return that == control;
+    }
+
+    bool operator==(const char c, const key& that)
+    {
+        return that == c;
+    }
+
+    bool operator!=(const special_key control, const key& that)
+    {
+        return that != control;
+    }
+
+    bool operator!=(const char c, const key& that)
+    {
+        return that != c;
+    }
+
+    editor_state::editor_state()
+    {
+        this->input.reserve(1024);
+    }
+
+    void editor_state::load(const std::string& text)
+    {
+        this->input = text;
+        this->position = this->input.size() + 1;
+    }
+
+    const std::string& editor_state::command_line() const noexcept
+    {
+        return this->input;
+    }
+
+    std::size_t editor_state::absolute_position() const noexcept
+    {
+        return this->prompt.size() + this->position;
+    }
+
+    std::size_t editor_state::relative_position() const noexcept
+    {
+        return this->position;
+    }
+
+    void editor_state::insert(const std::string& text)
+    {
+        this->input.insert(this->position - 1, text);
+        this->position += text.size();
+    }
+
+    void editor_state::insert(const key::char_t text)
+    {
+        if (text == 0u)
+        {
+            this->input.insert(this->position - 1, '\0', 1);
+            ++this->position;
+            return;
+        }
+        key::char_t buffer = boost::endian::native_to_big<key::char_t>(text);
+
+        const char *begin = reinterpret_cast<char *>(&buffer);
+        const char *end = begin + sizeof(key::char_t);
+        const char *significant = std::find_if(begin, end,
+                [](const char byte) {
+                    return byte != 0;
+                });
+
+        this->input.insert(this->position - 1, significant, end - significant);
+        this->position += end - significant;
+    }
+
+    action editor_state::process_keypress(const key& press)
+    {
+        if (press.is_control())
+        {
+            switch (press.control())
+            {
+                case special_key::arrow_left:
+                    if (this->position > 1)
+                    {
+                        --this->position;
+                    }
+                    return action::move;
+                case special_key::arrow_right:
+                    if (this->position + 1 < this->input.size() + this->prompt.size())
+                    {
+                        ++this->position;
+                    }
+                    return action::move;
+                case special_key::arrow_up:
+                case special_key::arrow_down:
+                    return action::history;
+                case special_key::home_key:
+                    this->position = 1;
+                    return action::move;
+                case special_key::end_key:
+                    this->position = this->input.size() + 1;
+                    return action::move;
+                default:
+                    return action::ignore;
+            }
+        }
+        else if (press.modified(modifier::ctrl))
+        {
+            switch (press.character())
+            {
+                case 'd':
+                    return action::finalize;
+                case 't':
+                    return action::complete;
+                default:
+                    return action::ignore;
+            }
+        }
+        else
+        {
+            switch (press.character())
+            {
+                case 127: // Backspace.
+                    if (this->position <= this->input.size() + 1 && this->position > 1)
+                    {
+                        --this->position;
+                        this->input.erase(this->position - 1, 1);
+                    }
+                    return action::redraw;
+                case 9: // Tab.
+                    return action::complete;
+                case '\r':
+                    return action::finalize;
+                default:
+                    if (this->position - 1 < input.size())
+                    {
+                        insert(press.character());
+                        return action::redraw;
+                    }
+                    else
+                    {
+                        insert(press.character());
+                        return action::write;
+                    }
+            }
+        }
+    }
+}

source/elna/arguments.d

@@ -0,0 +1,154 @@
+/**
+ * Argument parsing.
+ */
+module elna.arguments;
+
+import std.algorithm;
+import std.range;
+import std.sumtype;
+
+struct ArgumentError
+{
+    enum Type
+    {
+        expectedOutputFile,
+        noInput,
+        superfluousArguments,
+    }
+
+    private Type type_;
+    private string argument_;
+
+    @property Type type() const @nogc nothrow pure @safe
+    {
+        return this.type_;
+    }
+
+    @property string argument() const @nogc nothrow pure @safe
+    {
+        return this.argument_;
+    }
+
+    void toString(OR)(OR range)
+    if (isOutputRage!OR)
+    {
+        final switch (Type)
+        {
+            case Type.expectedOutputFile:
+                put(range, "Expected an output filename after -o");
+                break;
+            case Type.noInput:
+                put(range, "No input files specified");
+                break;
+        }
+    }
+}
+
+/**
+ * Supported compiler arguments.
+ */
+struct Arguments
+{
+    private bool assembler_;
+    private string output_;
+    private string inFile_;
+
+    @property string inFile() @nogc nothrow pure @safe
+    {
+        return this.inFile_;
+    }
+
+    /**
+     * Returns: Whether to generate assembly instead of an object file.
+     */
+    @property bool assembler() const @nogc nothrow pure @safe
+    {
+        return this.assembler_;
+    }
+
+    /**
+     * Returns: Output file.
+     */
+    @property string output() const @nogc nothrow pure @safe
+    {
+        return this.output_;
+    }
+
+    /**
+     * Parse command line arguments.
+     *
+     * The first argument is expected to be the program name (and it is
+     * ignored).
+     *
+     * Params:
+     *   arguments = Command line arguments.
+     *
+     * Returns: Parsed arguments or an error.
+     */
+    static SumType!(ArgumentError, Arguments) parse(string[] arguments)
+    @nogc nothrow pure @safe
+    {
+        if (!arguments.empty)
+        {
+            arguments.popFront;
+        }
+        alias ReturnType = typeof(return);
+
+        return parseArguments(arguments).match!(
+            (Arguments parsed) {
+                if (parsed.inFile is null)
+                {
+                    return ReturnType(ArgumentError(ArgumentError.Type.noInput));
+                }
+                else if (!arguments.empty)
+                {
+                    return ReturnType(ArgumentError(
+                        ArgumentError.Type.superfluousArguments,
+                        arguments.front
+                    ));
+                }
+                return ReturnType(parsed);
+            },
+            (ArgumentError argumentError) => ReturnType(argumentError)
+        );
+    }
+
+    private static SumType!(ArgumentError, Arguments) parseArguments(ref string[] arguments)
+    @nogc nothrow pure @safe
+    {
+        Arguments parsed;
+
+        while (!arguments.empty)
+        {
+            if (arguments.front == "-s")
+            {
+                parsed.assembler_ = true;
+            }
+            else if (arguments.front == "-o")
+            {
+                if (arguments.empty)
+                {
+                    return typeof(return)(ArgumentError(
+                        ArgumentError.Type.expectedOutputFile,
+                        arguments.front
+                    ));
+                }
+                arguments.popFront;
+                parsed.output_ = arguments.front;
+            }
+            else if (arguments.front == "--")
+            {
+                arguments.popFront;
+                parsed.inFile_ = arguments.front;
+                arguments.popFront;
+                break;
+            }
+            else if (!arguments.front.startsWith("-"))
+            {
+                parsed.inFile_ = arguments.front;
+            }
+            arguments.popFront;
+        }
+        return typeof(return)(parsed);
+    }
+}

source/elna/backend.d

@@ -0,0 +1,114 @@
+module elna.backend;
+
+import core.stdc.stdio;
+import core.stdc.stdlib;
+import core.stdc.string;
+import elna.elf;
+import elna.ir;
+import elna.extended;
+import elna.riscv;
+import elna.lexer;
+import elna.parser;
+import elna.result;
+import std.algorithm;
+import std.sumtype;
+import std.typecons;
+import tanya.os.error;
+import tanya.container.array;
+import tanya.container.string;
+import tanya.memory.allocator;
+
+private char* readSource(string source) @nogc
+{
+    enum size_t bufferSize = 255;
+    auto sourceFilename = String(source);
+
+    return readFile(sourceFilename).match!(
+        (ErrorCode errorCode) {
+            perror(sourceFilename.toStringz);
+            return null;
+        },
+        (Array!ubyte contents) {
+            char* cString = cast(char*) malloc(contents.length + 1);
+            memcpy(cString, contents.get.ptr, contents.length);
+            cString[contents.length] = '\0';
+
+            return cString;
+        }
+    );
+}
+
+int generate(string inFile, ref String outputFilename) @nogc
+{
+    auto sourceText = readSource(inFile);
+    if (sourceText is null)
+    {
+        return 3;
+    }
+    CompileError compileError = void;
+    size_t tokensCount;
+    auto tokens = lex(sourceText, &compileError, &tokensCount);
+    free(sourceText);
+    if (tokens is null)
+    {
+        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.what);
+        return 1;
+    }
+    auto ast = parse(tokens[0 .. tokensCount]);
+    if (!ast.valid)
+    {
+        compileError = ast.error.get;
+        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.what);
+        return 2;
+    }
+    auto transformVisitor = cast(TransformVisitor) malloc(__traits(classInstanceSize, TransformVisitor));
+    (cast(void*) transformVisitor)[0 .. __traits(classInstanceSize, TransformVisitor)] = __traits(initSymbol, TransformVisitor)[];
+
+    auto ir = transformVisitor.visit(ast.result);
+
+    transformVisitor.__xdtor();
+    free(cast(void*) transformVisitor);
+
+    auto handle = File.open(outputFilename.toStringz, BitFlags!(File.Mode)(File.Mode.truncate));
+    if (!handle.valid)
+    {
+        return 1;
+    }
+    auto program = writeNext(ir);
+    auto elf = Elf!ELFCLASS32(move(handle));
+    auto readOnlyData = Array!ubyte(cast(const(ubyte)[]) "%d\n".ptr[0 .. 4]); // With \0.
+
+    elf.addReadOnlyData(String(".CL0"), readOnlyData);
+    elf.addCode(program.name, program.text);
+
+    elf.addExternSymbol(String("printf"));
+    foreach (ref reference; program.symbols)
+    {
+        elf.Rela relocationEntry = {
+            r_offset: cast(elf.Addr) reference.offset
+        };
+        elf.Rela relocationSub = {
+            r_offset: cast(elf.Addr) reference.offset,
+            r_info: R_RISCV_RELAX
+        };
+
+        final switch (reference.target)
+        {
+            case Target.text:
+                relocationEntry.r_info = R_RISCV_CALL;
+                break;
+            case Target.high20:
+                relocationEntry.r_info = R_RISCV_HI20;
+                break;
+            case Target.lower12i:
+                relocationEntry.r_info = R_RISCV_LO12_I;
+                break;
+        }
+
+        elf.relocate(String(reference.name[0 .. strlen(reference.name)]), relocationEntry, relocationSub);
+    }
+
+    elf.finish();
+
+    return 0;
+}

source/elna/extended.d

@@ -3,7 +3,333 @@
  */
 module elna.extended;
 
+import core.stdc.errno;
+import core.stdc.stdio;
+import std.sumtype;
+import std.typecons;
+import tanya.os.error;
+import tanya.container.array;
+import tanya.container.string;
+
+/**
+ * File handle abstraction.
+ */
 struct File
 {
-    @disable this(this);
+    /// Plattform dependent file type.
+    alias Handle = FILE*;
+
+    /// Uninitialized file handle value.
+    enum Handle invalid = null;
+
+    /**
+     * Relative position.
+     */
+    enum Whence
+    {
+        /// Relative to the start of the file.
+        set = SEEK_SET,
+        /// Relative to the current cursor position.
+        currentt = SEEK_CUR,
+        /// Relative from the end of the file.
+        end = SEEK_END,
+    }
+
+    /**
+     * File open modes.
+     */
+    enum Mode
+    {
+        /// Open the file for reading.
+        read = 1 << 0,
+        /// Open the file for writing. The stream is positioned at the beginning
+        /// of the file.
+        write = 1 << 1,
+        /// Open the file for writing and remove its contents.
+        truncate = 1 << 2,
+        /// Open the file for writing. The stream is positioned at the end of
+        /// the file.
+        append = 1 << 3,
+    }
+
+    private enum Status
+    {
+        invalid,
+        owned,
+        borrowed,
+    }
+
+    private union Storage
+    {
+        Handle handle;
+        ErrorCode errorCode;
+    }
+    private Storage storage;
+    private Status status = Status.invalid;
+
+    @disable this(scope return ref File f);
+    @disable this();
+
+    /**
+     * Closes the file.
+     */
+    ~this() @nogc nothrow
+    {
+        if (this.status == Status.owned)
+        {
+            fclose(this.storage.handle);
+        }
+        this.storage.handle = invalid;
+        this.status = Status.invalid;
+    }
+
+    /**
+     * Construct the object with the given system handle. The won't be claused
+     * in the descructor if this constructor is used.
+     *
+     * Params:
+     *   handle = File handle to be wrapped by this structure.
+     */
+    this(Handle handle) @nogc nothrow pure @safe
+    {
+        this.storage.handle = handle;
+        this.status = Status.borrowed;
+    }
+
+    /**
+     * Returns: Plattform dependent file handle.
+     */
+    @property Handle handle() @nogc nothrow pure @trusted
+    {
+        return valid ? this.storage.handle : invalid;
+    }
+
+    /**
+     * Returns: An error code if an error has occurred.
+     */
+    @property ErrorCode errorCode() @nogc nothrow pure @safe
+    {
+        return valid ? ErrorCode() : this.storage.errorCode;
+    }
+
+    /**
+     * Returns: Whether a valid, opened file is represented.
+     */
+    @property bool valid() @nogc nothrow pure @safe
+    {
+        return this.status != Status.invalid;
+    }
+
+    /**
+     * Transfers the file into invalid state.
+     *
+     * Returns: The old file handle.
+     */
+    Handle reset() @nogc nothrow pure @safe
+    {
+        if (!valid)
+        {
+            return invalid;
+        }
+        auto oldHandle = handle;
+
+        this.status = Status.invalid;
+        this.storage.errorCode = ErrorCode();
+
+        return oldHandle;
+    }
+
+    /**
+     * Sets stream position in the file.
+     *
+     * Params:
+     *   offset = File offset.
+     *   whence = File position to add the offset to.
+     *
+     * Returns: Error code if any.
+     */
+    ErrorCode seek(size_t offset, Whence whence) @nogc nothrow
+    {
+        if (!valid)
+        {
+            return ErrorCode(ErrorCode.ErrorNo.badDescriptor);
+        }
+        if (fseek(this.storage.handle, offset, whence))
+        {
+            return ErrorCode(cast(ErrorCode.ErrorNo) errno);
+        }
+        return ErrorCode();
+    }
+
+    /**
+     * Returns: Current offset or an error.
+     */
+    SumType!(ErrorCode, size_t) tell() @nogc nothrow
+    {
+        if (!valid)
+        {
+            return typeof(return)(ErrorCode(ErrorCode.ErrorNo.badDescriptor));
+        }
+        auto result = ftell(this.storage.handle);
+
+        if (result < 0)
+        {
+            return typeof(return)(ErrorCode(cast(ErrorCode.ErrorNo) errno));
+        }
+        return typeof(return)(cast(size_t) result);
+    }
+
+    /**
+     * Params:
+     *   buffer = Destination buffer.
+     *
+     * Returns: Bytes read. $(D_PSYMBOL ErrorCode.ErrorNo.success) means that
+     *          while reading the file an unknown error has occurred.
+     */
+    SumType!(ErrorCode, size_t) read(ubyte[] buffer) @nogc nothrow
+    {
+        if (!valid)
+        {
+            return typeof(return)(ErrorCode(ErrorCode.ErrorNo.badDescriptor));
+        }
+        const bytesRead = fread(buffer.ptr, 1, buffer.length, this.storage.handle);
+        if (bytesRead == buffer.length || eof())
+        {
+            return typeof(return)(bytesRead);
+        }
+        return typeof(return)(ErrorCode());
+    }
+
+    /**
+     * Params:
+     *   buffer = Source buffer.
+     *
+     * Returns: Bytes written. $(D_PSYMBOL ErrorCode.ErrorNo.success) means that
+     *          while reading the file an unknown error has occurred.
+     */
+    SumType!(ErrorCode, size_t) write(const(ubyte)[] buffer) @nogc nothrow
+    {
+        if (!valid)
+        {
+            return typeof(return)(ErrorCode(ErrorCode.ErrorNo.badDescriptor));
+        }
+        const bytesWritten = fwrite(buffer.ptr, 1, buffer.length, this.storage.handle);
+        if (bytesWritten == buffer.length)
+        {
+            return typeof(return)(buffer.length);
+        }
+        return typeof(return)(ErrorCode());
+    }
+
+    /**
+     * Returns: EOF status of the file.
+     */
+    bool eof() @nogc nothrow
+    {
+        return valid && feof(this.storage.handle) != 0;
+    }
+
+    /**
+     * Constructs a file object that will be closed in the destructor.
+     *
+     * Params:
+     *   filename = The file to open.
+     *
+     * Returns: Opened file or an error.
+     */
+    static File open(const(char)* filename, BitFlags!Mode mode) @nogc nothrow
+    {
+        char[3] modeBuffer = "\0\0\0";
+
+        if (mode.truncate)
+        {
+            modeBuffer[0] = 'w';
+            if (mode.read)
+            {
+                modeBuffer[1] = '+';
+            }
+        }
+        else if (mode.append)
+        {
+            modeBuffer[0] = 'a';
+            if (mode.read)
+            {
+                modeBuffer[1] = '+';
+            }
+        }
+        else if (mode.read)
+        {
+            modeBuffer[0] = 'r';
+            if (mode.write)
+            {
+                modeBuffer[1] = '+';
+            }
+        }
+
+        auto newHandle = fopen(filename, modeBuffer.ptr);
+        auto newFile = File(newHandle);
+
+        if (newHandle is null)
+        {
+            newFile.status = Status.invalid;
+            newFile.storage.errorCode = ErrorCode(cast(ErrorCode.ErrorNo) errno);
+        }
+        else
+        {
+            if (mode == BitFlags!Mode(Mode.write))
+            {
+                rewind(newHandle);
+            }
+            newFile.status = Status.owned;
+        }
+
+        return newFile;
+    }
+}
+
+/**
+ * Reads the whole file and returns its contents.
+ *
+ * Params:
+ *   sourceFilename = Source filename.
+ *
+ * Returns: File contents or an error.
+ *
+ * See_Also: $(D_PSYMBOL File.read)
+ */
+SumType!(ErrorCode, Array!ubyte) readFile(String sourceFilename) @nogc
+{
+    enum size_t bufferSize = 255;
+    auto sourceFile = File.open(sourceFilename.toStringz, BitFlags!(File.Mode)(File.Mode.read));
+
+    if (!sourceFile.valid)
+    {
+        return typeof(return)(sourceFile.errorCode);
+    }
+    Array!ubyte sourceText;
+    size_t totalRead;
+    size_t bytesRead;
+    do
+    {
+        sourceText.length = sourceText.length + bufferSize;
+        const readStatus = sourceFile
+            .read(sourceText[totalRead .. $].get)
+            .match!(
+                (ErrorCode errorCode) => nullable(errorCode),
+                (size_t bytesRead_) {
+                    bytesRead = bytesRead_;
+                    return Nullable!ErrorCode();
+                }
+            );
+        if (!readStatus.isNull)
+        {
+            return typeof(return)(readStatus.get);
+        }
+        totalRead += bytesRead;
+    }
+    while (bytesRead == bufferSize);
+
+    sourceText.length = totalRead;
+
+    return typeof(return)(sourceText);
 }

source/elna/generator.d

@@ -1,660 +0,0 @@
-module elna.generator;
-
-import core.stdc.stdio;
-import core.stdc.stdlib;
-import core.stdc.string;
-import elna.ir;
-import tanya.container.array;
-import tanya.container.string;
-import tanya.memory.mmappool;
-import tanya.format;
-
-/// Unsigned program address.
-alias Elf64_Addr = void*;
-/// Unsigned file offset.
-alias Elf64_Off = ulong;
-/// Unsigned medium integer.
-alias Elf64_Half = ushort;
-/// Unsigned integer.
-alias Elf64_Word = uint;
-/// Signed integer.
-alias Elf64_Sword = int;
-/// Unsigned long integer.
-alias Elf64_Xword = ulong;
-/// Signed long integer.
-alias Elf64_Sxword = long;
-
-enum size_t EI_INDENT = 16;
-
-/**
- * File header.
- */
-struct Elf64_Ehdr
-{
-    /// ELF identification.
-    ubyte[EI_INDENT] e_ident;
-    /// Object file type.
-    Elf64_Half e_type;
-    /// Machine type.
-    Elf64_Half e_machine;
-    /// Object file version
-    Elf64_Word e_version;
-    /// Entry point address.
-    Elf64_Addr e_entry;
-    /// Program header offset.
-    Elf64_Off e_phoff;
-    /// Section header offset.
-    Elf64_Off e_shoff;
-    /// Processor-specific flags.
-    Elf64_Word e_flags;
-    /// ELF header size.
-    Elf64_Half e_ehsize;
-    /// Size of program header entry.
-    Elf64_Half e_phentsize;
-    /// Number of program header entries.
-    Elf64_Half e_phnum;
-    /// Size of section header entry.
-    Elf64_Half e_shentsize;
-    /// Number of section header entries.
-    Elf64_Half e_shnum;
-    /// Section name string table index.
-    Elf64_Half e_shstrndx;
-}
-
-/**
- * Section header.
- */
-struct Elf64_Shdr
-{
-    /// Section name.
-    Elf64_Word sh_name;
-    /// Section type.
-    Elf64_Word sh_type;
-    /// Section attributes.
-    Elf64_Xword sh_flags;
-    /// Virtual address in memory.
-    Elf64_Addr sh_addr;
-    /// Offset in file.
-    Elf64_Off sh_offset;
-    /// Size of section.
-    Elf64_Xword sh_size;
-    /// Link to other section.
-    Elf64_Word sh_link;
-    /// Miscellaneous information.
-    Elf64_Word sh_info;
-    /// Address alignment boundary.
-    Elf64_Xword sh_addralign;
-    /// Size of entries, if section has table.
-    Elf64_Xword sh_entsize;
-}
-
-struct Elf64_Sym
-{
-    /// Symbol name.
-    Elf64_Word st_name;
-    /// Type and Binding attributes.
-    ubyte st_info;
-    /// Reserved.
-    ubyte st_other;
-    /// Section table index.
-    Elf64_Half st_shndx;
-    /// Symbol value.
-    Elf64_Addr st_value;
-    /// Size of object (e.g., common).
-    Elf64_Xword st_size;
-}
-
-/// Section Types, sh_type.
-enum : Elf64_Word
-{
-    /// Marks an unused section header.
-    SHT_NULL = 0,
-    ///  Contains information defined by the program.
-    SHT_PROGBITS = 1,
-    /// Contains a linker symbol table.
-    SHT_SYMTAB = 2,
-    /// Contains a string table.
-    SHT_STRTAB = 3,
-    /// Contains “Rela” type relocation entries.
-    SHT_RELA = 4,
-    /// Contains a symbol hash table
-    SHT_HASH = 5,
-    /// Contains dynamic linking tables
-    SHT_DYNAMIC = 6,
-    /// Contains note information
-    SHT_NOTE = 7,
-    /// Contains uninitialized space; does not occupy any space in the file.
-    SHT_NOBITS = 8,
-    /// Contains "Rel" type relocation entries.
-    SHT_REL = 9,
-    /// Reserved.
-    SHT_SHLIB = 10,
-    /// Contains a dynamic loader symbol table.
-    SHT_DYNSYM = 11,
-    /// Environment-specific use.
-    SHT_LOOS = 0x60000000,
-    SHT_HIOS = 0x6FFFFFFF,
-    /// Processor-specific use.
-    SHT_LOPROC = 0x70000000,
-    SHT_HIPROC = 0x7FFFFFFF,
-}
-
-/**
- * Section Attributes, sh_flags.
- */
-enum : Elf64_Xword
-{
-    /// Section contains writable data.
-    SHF_WRITE = 0x1,
-    /// Section is allocated in memory image of program.
-    SHF_ALLOC = 0x2,
-    /// Section contains executable instructions.
-    SHF_EXECINSTR = 0x4,
-    /// Environment-specific use.
-    SHF_MASKOS = 0x0F000000,
-    /// Processor-specific use.
-    SHF_MASKPROC = 0xF0000000,
-}
-
-enum : Elf64_Word
-{
-    /// Not visible outside the object file.
-    STB_LOCAL = 0,
-    /// Global symbol, visible to all object files.
-    STB_GLOBAL = 1,
-    /// Global scope, but with lower precedence than global symbols.
-    STB_WEAK = 2,
-    /// Environment-specific use.
-    STB_LOOS = 10,
-    STB_HIOS = 12,
-    /// Processor-specific use.
-    STB_LOPROC = 13,
-    STB_HIPROC = 15,
-}
-
-enum : Elf64_Word
-{
-    /// No type specified (e.g., an absolute symbol).
-    STT_NOTYPE = 0,
-    /// Data object.
-    STT_OBJECT = 1,
-    /// Function entry point.
-    STT_FUNC = 2,
-    /// Symbol is associated with a section.
-    STT_SECTION = 3,
-    /// Source file associated with the object file.
-    STT_FILE = 4,
-    /// Environment-specific use.
-    STT_LOOS = 10,
-    STT_HIOS = 12,
-    /// Processor-specific use.
-    STT_LOPROC = 13,
-    STT_HIPROC = 15,
-}
-
-Elf64_Ehdr makeFileHeader(Elf64_Off sectionHeaderOffset,
-        Elf64_Half sectionHeaderCount,
-        Elf64_Half stringIndex) @nogc
-{
-    Elf64_Ehdr header;
-
-    // Magic number.
-    header.e_ident[0] = '\x7f';
-    header.e_ident[1] = 'E';
-    header.e_ident[2] = 'L';
-    header.e_ident[3] = 'F';
-
-    // File class.
-    header.e_ident[4] = EI_CLASS.ELFCLASS64;
-
-    // Data encoding.
-    header.e_ident[5] = EI_DATA.ELFDATA2LSB;
-
-    // Version.
-    header.e_ident[6] = EV_CURRENT;
-
-    // OS/ABI identification.
-    header.e_ident[7] = EI_OSABI.ELFOSABI_SYSV;
-
-    // ABI version.
-    header.e_ident[8] = 0;
-
-    // Size of e_ident[].
-    header.e_ident[15] = 0;
-
-    header.e_type = ET_REL;
-    header.e_machine = 0x3e; // EM_X86_64: AMD x86-64 architecture
-    header.e_version = EV_CURRENT;
-    header.e_entry = null;
-    header.e_phoff = 0;
-    header.e_shoff = sectionHeaderOffset;
-    header.e_flags = 0;
-    header.e_ehsize = Elf64_Ehdr.sizeof;
-    header.e_phentsize = 0;
-    header.e_phnum = 0;
-    header.e_shentsize = Elf64_Shdr.sizeof;
-    header.e_shnum = sectionHeaderCount;
-    header.e_shstrndx = stringIndex;
-
-    return header;
-}
-
-enum char[33] sectionStringTable = "\0.symtab\0.strtab\0.shstrtab\0.text\0";
-
-Elf64_Shdr makeTextHeader(Elf64_Off offset, Elf64_Xword size) @nogc
-{
-    Elf64_Shdr table;
-
-    table.sh_name = 0x1b;
-    table.sh_type = SHT_PROGBITS;
-    table.sh_flags = SHF_EXECINSTR | SHF_ALLOC;
-    table.sh_addr = null;
-    table.sh_offset = offset;
-    table.sh_size = size;
-    table.sh_link = SHN_UNDEF;
-    table.sh_info = 0;
-    table.sh_addralign = 1;
-    table.sh_entsize = 0;
-
-    return table;
-}
-
-Elf64_Shdr makeDataHeader(Elf64_Off offset, Elf64_Xword size) @nogc
-{
-    Elf64_Shdr table;
-
-    table.sh_name = 0x21;
-    table.sh_type = SHT_PROGBITS;
-    table.sh_flags = SHF_WRITE | SHF_ALLOC;
-    table.sh_addr = null;
-    table.sh_offset = offset;
-    table.sh_size = size;
-    table.sh_link = SHN_UNDEF;
-    table.sh_info = 0;
-    table.sh_addralign = 1;
-    table.sh_entsize = 0;
-
-    return table;
-}
-
-Elf64_Shdr makeSymtableHeader(Elf64_Off offset, Elf64_Xword size, Elf64_Word entriesCount) @nogc
-{
-    Elf64_Shdr table;
-
-    table.sh_name = 0x01;
-    table.sh_type = SHT_SYMTAB;
-    table.sh_flags = 0;
-    table.sh_addr = null;
-    table.sh_offset = offset;
-    table.sh_size = size;
-    table.sh_link = 0x03; // String table used by entries in this section.
-    table.sh_info = entriesCount;
-    table.sh_addralign = 8;
-    table.sh_entsize = Elf64_Sym.sizeof;
-
-    return table;
-}
-
-Elf64_Shdr makeStringHeader(Elf64_Word stringIndex, Elf64_Off offset, Elf64_Xword size) @nogc
-{
-    Elf64_Shdr table;
-
-    table.sh_name = stringIndex;
-    table.sh_type = SHT_STRTAB;
-    table.sh_flags = 0;
-    table.sh_addr = null;
-    table.sh_offset = offset;
-    table.sh_size = size;
-    table.sh_link = SHN_UNDEF;
-    table.sh_info = 0;
-    table.sh_addralign = 1;
-    table.sh_entsize = 0;
-
-    return table;
-}
-
-Elf64_Shdr makeInitialHeader() @nogc
-{
-    Elf64_Shdr table;
-
-    table.sh_name = 0;
-    table.sh_type = SHT_NULL;
-    table.sh_flags = 0;
-    table.sh_addr = null;
-    table.sh_offset = 0;
-    table.sh_size = 0;
-    table.sh_link = SHN_UNDEF;
-    table.sh_info = 0;
-    table.sh_addralign = 0;
-    table.sh_entsize = 0;
-
-    return table;
-}
-
-Elf64_Sym makeInitialSymTable() @nogc
-{
-    Elf64_Sym table;
-
-    table.st_name = 0;
-    table.st_info = 0;
-    table.st_other = 0;
-    table.st_shndx = 0;
-    table.st_value = null;
-    table.st_size = 0;
-
-    return table;
-}
-
-Elf64_Sym makeMainSymTable(Elf64_Half textIndex) @nogc
-{
-    Elf64_Sym table;
-
-    table.st_name = 0x01;
-    table.st_info = ELF32_ST_INFO(STB_GLOBAL, STT_FUNC);
-    table.st_other = 0;
-    table.st_shndx = textIndex;
-    table.st_value = null;
-    table.st_size = 0;
-
-    return table;
-}
-
-ubyte ELF32_ST_BIND(ubyte i) @nogc nothrow pure @safe
-{
-    return i >> 4;
-}
-
-ubyte ELF32_ST_TYPE(ubyte i) @nogc nothrow pure @safe
-{
-    return i & 0xf;
-}
-
-ubyte ELF32_ST_INFO(ubyte b, ubyte t) @nogc nothrow pure @safe
-{
-    return cast(ubyte) ((b << 4) + (t & 0xf));
-}
-
-/// Special Section Indices.
-enum : Elf64_Half
-{
-    /// Used to mark an undefined or meaningless section reference.
-    SHN_UNDEF = 0,
-    /// Processor-specific use.
-    SHN_LOPROC = 0xFF00,
-    SHN_HIPROC = 0xFF1F,
-    /// Environment-specific use.
-    SHN_LOOS = 0xFF20,
-    SHN_HIOS = 0xFF3F,
-    /// Indicates that the corresponding reference is an absolute value.
-    SHN_ABS = 0xFFF1,
-    /**
-     * Indicates a symbol that has been declared as a common block (Fortran
-     * COMMON or C tentative declaration).
-     */
-    SHN_COMMON = 0xFFF2,
-}
-
-/**
- * Object File Classes, e_ident[EI_CLASS].
- */
-enum EI_CLASS : ubyte
-{
-    /// 32-bit objects.
-    ELFCLASS32 = 1,
-    /// 64-bit objects.
-    ELFCLASS64 = 2,
-}
-
-enum ubyte EV_CURRENT = 1;
-
-/**
- * Data Encodings, e_ident[EI_DATA].
- */
-enum EI_DATA : ubyte
-{
-    /// Object file data structures are little-endian.
-    ELFDATA2LSB = 1,
-    /// Object file data structures are big-endian.
-    ELFDATA2MSB = 2,
-}
-
-/**
- * Operating System and ABI Identifiers, e_ident[EI_OSABI].
- */
-enum EI_OSABI : ubyte
-{
-    /// System V ABI.
-    ELFOSABI_SYSV = 0,
-    /// HP-UX operating system.
-    ELFOSABI_HPUX = 1,
-    /// Standalone (embedded) application.
-    ELFOSABI_STANDALONE = 255,
-}
-
-enum : Elf64_Half
-{
-    ET_NONE = 0, /// No file type.
-    ET_REL = 1, /// Relocatable object file.
-    ET_EXEC = 2, /// Executable file.
-    ET_DYN = 3, /// Shared object file.
-    ET_CORE = 4, /// Core file.
-    ET_LOOS = 0xFE00, /// Environment-specific use.
-    ET_HIOS = 0xFEFF,
-    ET_LOPROC = 0xFF00, /// Processor-specific use.
-    ET_HIPROC = 0xFFFF,
-}
-
-private size_t pad(size_t value) @nogc
-{
-    return (value / 8 + 1) * 8;
-}
-
-struct Symbol
-{
-    String name;
-    Array!ubyte instructions;
-}
-
-/*
-.text
-    .globl main
-    .type main, @function
-main:
-    movl $3, %eax
-    ret
-*/
-immutable ubyte[] instructions = [
-    // Opcode of pushq is “0x50 + r”, where “r” is the register opcode.
-    // Register opcode of %rbq is 5.
-    0x50 + 5, // push% %rbp
-    0x48, 0x89, 0xe5, // movq %rsp, %rbp
-
-    0xb8, 0x03, 0x00, 0x00, 0x00, // movl $3, %eax
-
-    // Epilogue.
-    0x48, 0x89, 0xec, // movq %rbp, %rsp
-    0x58 + 5, // popq %rbp
-    0xc3, // ret
-];
-
-void writeObject(Definition ast, String outputFilename) @nogc
-{
-    auto handle = fopen(outputFilename.toStringz, "wb");
-
-    if (handle is null)
-    {
-        perror("writing sample");
-        return;
-    }
-    scope (exit)
-    {
-        fclose(handle);
-    }
-
-    size_t currentOffset = Elf64_Ehdr.sizeof;
-    Array!Elf64_Shdr sectionHeaders;
-    Array!Elf64_Sym symbolEntries;
-
-    // Prologue
-    Array!ubyte asmTemplate = Array!ubyte(cast(ubyte[]) [
-        // Opcode of pushq is “0x50 + r”, where “r” is the register opcode.
-        // Register opcode of %rbq is 5.
-        0x50 + 5, // pushq %rbp
-        0x48, 0x89, 0xe5, // movq %rsp, %rbp
-    ]);
-    int i = 1;
-    foreach (statement; ast.statements[])
-    {
-        if ((cast(Number) statement.subroutine.lhs) !is null)
-        {
-            // Opcode of mov is “0xb8 + r”, where “r” is the register opcode.
-            // Register opcode of %eax is 0.
-            asmTemplate.insertBack(cast(ubyte) 0xb8); // movl $x, %eax; where $x is a number.
-            asmTemplate.insertBack((cast(ubyte*) &(cast(Number) statement.subroutine.lhs).value)[0 .. int.sizeof]);
-        }
-        else if ((cast(Variable) statement.subroutine.lhs) !is null)
-        {
-            // movl -x(%rbp), %ebx; where x is a number.
-            asmTemplate.insertBack(cast(ubyte[]) [0x8b, 0x45]);
-            const disposition = (cast(Variable) statement.subroutine.lhs).counter * (-4);
-            asmTemplate.insertBack((cast(ubyte*) &disposition)[0 .. 1]);
-        }
-        if ((cast(Number) statement.subroutine.rhs) !is null)
-        {
-            // Opcode of mov is “0xb8 + r”, where “r” is the register opcode.
-            // Register opcode of %ebx is 3.
-            asmTemplate.insertBack(cast(ubyte) 0xbb); // movl $x, %ebx; where $x is a number.
-            asmTemplate.insertBack((cast(ubyte*) &(cast(Number) statement.subroutine.rhs).value)[0 .. int.sizeof]);
-        }
-        else if ((cast(Variable) statement.subroutine.rhs) !is null)
-        {
-            // movl -x(%rbp), %ebx; where x is a number.
-            asmTemplate.insertBack(cast(ubyte[]) [0x8b, 0x5d]);
-            const disposition = (cast(Variable) statement.subroutine.rhs).counter * (-4);
-            asmTemplate.insertBack((cast(ubyte*) &disposition)[0 .. 1]);
-        }
-        // Calculate the result and assign it to a variable on the stack.
-        asmTemplate.insertBack(cast(ubyte[]) [0x01, 0xd8]); // add %ebx, %eax
-
-        asmTemplate.insertBack(cast(ubyte[]) [0x89, 0x45]); // movl %eax, -x(%rbp); where x is a number.
-        const disposition = i * (-4);
-        asmTemplate.insertBack((cast(ubyte*) &disposition)[0 .. 1]);
-        ++i;
-    }
-    // Epilogue.
-    asmTemplate.insertBack(cast(ubyte[]) [
-        0x48, 0x89, 0xec, // movq %rbp, %rsp
-        0x58 + 5, // popq %rbp
-        0xc3, // ret
-    ]);
-
-    Symbol[1] symbols = [Symbol(String("main"), asmTemplate)];
-
-    sectionHeaders.insertBack(makeInitialHeader());
-    symbolEntries.insertBack(makeInitialSymTable());
-
-    String stringTable = String("\0");
-    foreach (symbol; symbols[])
-    {
-        stringTable.insertBack(symbol.name[]);
-        stringTable.insertBack('\0');
-
-        sectionHeaders.insertBack(makeTextHeader(currentOffset, symbol.instructions.length));
-        currentOffset = pad(currentOffset + symbol.instructions.length);
-
-        symbolEntries.insertBack(makeMainSymTable(cast(Elf64_Half) (sectionHeaders.length - 1)));
-    }
-
-    const symbolTableSize = (symbols.length + 1) * Elf64_Sym.sizeof;
-    sectionHeaders.insertBack(makeSymtableHeader(currentOffset, symbolTableSize, symbols.length));
-    currentOffset += symbolTableSize;
-
-    sectionHeaders.insertBack(makeStringHeader(0x09, currentOffset, stringTable.length));
-    currentOffset += stringTable.length;
-
-    sectionHeaders.insertBack(makeStringHeader(0x11, currentOffset, sectionStringTable.length));
-    currentOffset = pad(currentOffset + sectionStringTable.length);
-
-    auto fileHeader = makeFileHeader(currentOffset, 5, 4);
-
-    version (none)
-    {
-        printf("%.2x\n", cast(uint) currentOffset);
-    }
-    ubyte[8] padding = 0;
-    size_t codeLength = stringTable.length + sectionStringTable.length;
-
-    fwrite(&fileHeader, 8, Elf64_Ehdr.sizeof / 8, handle);
-    foreach (symbol; symbols[])
-    {
-        immutable size_t instructionsLength = pad(symbol.instructions.length);
-        fwrite(symbol.instructions.get.ptr, 1, symbol.instructions.length, handle);
-        fwrite(padding.ptr, 1, instructionsLength - symbol.instructions.length, handle);
-        codeLength += instructionsLength;
-    }
-    fwrite(symbolEntries.get.ptr, Elf64_Sym.sizeof, symbolEntries.length, handle);
-    fwrite(stringTable.get.ptr, 1, stringTable.length, handle);
-    fwrite(sectionStringTable.ptr, 1, sectionStringTable.length, handle);
-    fwrite(padding.ptr, pad(codeLength) - codeLength, 1, handle);
-    fwrite(sectionHeaders.get.ptr, Elf64_Shdr.sizeof, sectionHeaders.length, handle);
-}
-
-String generate(Definition ast) @nogc
-{
-    // Prologue
-    String asmTemplate = ".text
-    .globl main
-    .type main, @function
-main:
-    pushq %rbp
-    movq %rsp, %rbp
-";
-
-    /* Allocate space on the stack for local variables.
-    asmTemplate.insertBack("    sub $");
-    asmTemplate.insertBack(format!"{}"(ast.statements.length)[]);
-    asmTemplate.insertBack(", $esp\n"); */
-
-    int i = 1;
-    foreach (statement; ast.statements[])
-    {
-        if ((cast(Number) statement.subroutine.lhs) !is null)
-        {
-            asmTemplate.insertBack("    movl $");
-            asmTemplate.insertBack(format!"{}"((cast(Number) statement.subroutine.lhs).value)[]);
-            asmTemplate.insertBack(", %eax\n");
-        }
-        else if ((cast(Variable) statement.subroutine.lhs) !is null)
-        {
-            asmTemplate.insertBack("    movl -");
-            asmTemplate.insertBack(format!"{}"((cast(Variable) statement.subroutine.lhs).counter * 4)[]);
-            asmTemplate.insertBack("(%rbp), %eax\n");
-        }
-        if ((cast(Number) statement.subroutine.rhs) !is null)
-        {
-            asmTemplate.insertBack("    movl $");
-            asmTemplate.insertBack(format!"{}"((cast(Number) statement.subroutine.rhs).value)[]);
-            asmTemplate.insertBack(", %ebx\n");
-        }
-        else if ((cast(Variable) statement.subroutine.rhs) !is null)
-        {
-            asmTemplate.insertBack("    movl -");
-            asmTemplate.insertBack(format!"{}"((cast(Variable) statement.subroutine.rhs).counter * 4)[]);
-            asmTemplate.insertBack("(%rbp), %ebx\n");
-        }
-        // Calculate the result and assign it to a variable on the stack.
-        asmTemplate.insertBack("    add %ebx, %eax\n");
-        asmTemplate.insertBack("    movl %eax, -");
-        asmTemplate.insertBack(format!"{}"(i * 4)[]);
-        asmTemplate.insertBack("(%rbp)\n");
-        ++i;
-    }
-
-    // Epilogue.
-    asmTemplate.insertBack("    movq %rbp, %rsp
-    popq %rbp
-    ret
-");
-
-    return asmTemplate;
-}

source/elna/ir.d

@@ -1,112 +1,213 @@
 module elna.ir;
 
+import core.stdc.stdlib;
 import parser = elna.parser;
 import tanya.container.array;
 import tanya.container.hashtable;
 import tanya.container.string;
 import tanya.memory.allocator;
-import tanya.memory.mmappool;
+public import elna.parser : BinaryOperator;
+
+/**
+ * Mapping between the parser and IR AST.
+ */
+struct ASTMapping
+{
+    alias Node = .Node;
+    alias Definition = .Definition;
+    alias Statement = .Operand;
+    alias BangStatement = .Operand;
+    alias Block = .Definition;
+    alias Expression = .Operand;
+    alias Number = .Number;
+    alias Variable = .Number;
+    alias BinaryExpression = .Variable;
+
+}
+
+/**
+ * IR visitor.
+*/
+extern(C++, "elna", "ir")
+abstract class IRVisitor
+{
+    abstract void visit(Node) @nogc;
+    abstract void visit(Definition) @nogc;
+    abstract void visit(Operand) @nogc;
+    abstract void visit(BinaryExpression) @nogc;
+    abstract void visit(Variable) @nogc;
+    abstract void visit(Number) @nogc;
+}
+
+/**
+ * AST node.
+ */
+extern(C++, "elna", "ir")
+abstract class Node
+{
+    abstract void accept(IRVisitor) @nogc;
+}
 
 /**
  * Definition.
  */
-class Definition
+extern(C++, "elna", "ir")
+class Definition : Node
 {
-    char[] identifier;
+    BinaryExpression* statements;
-    Array!Statement statements;
+    size_t statementsLength;
-    Array!VariableDeclaration variableDeclarations;
+    Operand result;
+
+    override void accept(IRVisitor visitor) @nogc;
 }
 
-class Statement
+extern(C++, "elna", "ir")
-{
+abstract class Statement : Node
-    Subroutine subroutine;
-}
-
-abstract class Expression
 {
 }
 
-class Number : Expression
+extern(C++, "elna", "ir")
+abstract class Operand : Node
+{
+    override void accept(IRVisitor visitor) @nogc;
+}
+
+extern(C++, "elna", "ir")
+class Number : Operand
 {
     int value;
+
+    override void accept(IRVisitor visitor) @nogc;
 }
 
-class Variable : Expression
+extern(C++, "elna", "ir")
+class Variable : Operand
 {
     size_t counter;
+
+    override void accept(IRVisitor visitor) @nogc;
 }
 
-class VariableDeclaration
+extern(C++, "elna", "ir")
+class BinaryExpression : Statement
 {
-    String identifier;
+    Operand lhs, rhs;
+    BinaryOperator operator;
+
+    this(Operand lhs, Operand rhs, BinaryOperator operator) @nogc;
+
+    override void accept(IRVisitor visitor) @nogc;
 }
 
-class Subroutine
+extern(C++, "elna", "ir")
+class BangExpression : Statement
 {
-    Expression lhs, rhs;
+    Operand operand;
+
+    this(Operand operand);
+
+    override void accept(IRVisitor visitor) @nogc;
 }
 
-private Number transformNumber(parser.Number number) @nogc
+final class TransformVisitor : parser.ParserVisitor!ASTMapping
 {
-    return MmapPool.instance.make!Number(number.value);
+    private HashTable!(String, int) constants;
-}
+    private BinaryExpression* statements;
+    private size_t statementsLength;
 
-private Variable transformSubroutine(parser.Subroutine subroutine,
+    ASTMapping.Node visit(parser.Node node) @nogc
-        ref Array!Statement statements,
+    {
-        ref HashTable!(String, int) constants) @nogc
+        assert(false, "Not implemented");
-{
+    }
-    auto target = MmapPool.instance.make!Subroutine;
-    target.lhs = transformExpression(subroutine.lhs, statements, constants);
-    target.rhs = transformExpression(subroutine.rhs, statements, constants);
 
-    auto newStatement = MmapPool.instance.make!Statement;
+    ASTMapping.Definition visit(parser.Definition definition) @nogc
-    newStatement.subroutine = target;
+    {
-    statements.insertBack(newStatement);
+        assert(false, "Not implemented");
+    }
 
-    auto newVariable = MmapPool.instance.make!Variable;
+    ASTMapping.BangStatement visit(parser.BangStatement statement) @nogc
-    newVariable.counter = statements.length;
+    {
+        return statement.expression.accept(this);
+    }
 
-    return newVariable;
+    ASTMapping.Block visit(parser.Block block) @nogc
-}
+    {
+        auto target = defaultAllocator.make!Definition;
+        this.constants = transformConstants(block.definitions);
 
-private Expression transformExpression(parser.Expression expression,
+        target.result = block.statement.accept(this);
-        ref Array!Statement statements,
+        target.statements = this.statements;
-        ref HashTable!(String, int) constants) @nogc
+        target.statementsLength = this.statementsLength;
-{
+
+        return target;
+    }
+
+    ASTMapping.Expression visit(parser.Expression expression) @nogc
+    {
         if ((cast(parser.Number) expression) !is null)
         {
-        auto numberExpression = MmapPool.instance.make!Number;
+            return (cast(parser.Number) expression).accept(this);
-        numberExpression.value = (cast(parser.Number) expression).value;
-
-        return numberExpression;
         }
         if ((cast(parser.Variable) expression) !is null)
         {
-        auto numberExpression = MmapPool.instance.make!Number;
+            return (cast(parser.Variable) expression).accept(this);
-        numberExpression.value = constants[(cast(parser.Variable) expression).identifier];
+        }
+        else if ((cast(parser.BinaryExpression) expression) !is null)
+        {
+            return (cast(parser.BinaryExpression) expression).accept(this);
+        }
+        assert(false, "Invalid expression type");
+    }
+
+    ASTMapping.Number visit(parser.Number number) @nogc
+    {
+        auto numberExpression = defaultAllocator.make!Number;
+        numberExpression.value = number.value;
 
         return numberExpression;
     }
-    else if ((cast(parser.Subroutine) expression) !is null)
-    {
-        return transformSubroutine(cast(parser.Subroutine) expression, statements, constants);
-    }
-    return null;
-}
 
-Expression transformStatement(parser.Statement statement,
+    ASTMapping.Variable visit(parser.Variable variable) @nogc
-        ref Array!Statement statements,
+    {
-        ref HashTable!(String, int) constants) @nogc
+        auto numberExpression = defaultAllocator.make!Number;
-{
+        numberExpression.value = this.constants[variable.identifier];
+
+        return numberExpression;
+    }
+
+    ASTMapping.BinaryExpression visit(parser.BinaryExpression binaryExpression) @nogc
+    {
+        auto target = defaultAllocator.make!BinaryExpression(
+            binaryExpression.lhs.accept(this),
+            binaryExpression.rhs.accept(this),
+            binaryExpression.operator
+        );
+        this.statements = cast(BinaryExpression*)
+            realloc(this.statements, (this.statementsLength + 1) * BinaryExpression.sizeof);
+        this.statements[this.statementsLength++] = target;
+
+        auto newVariable = defaultAllocator.make!Variable;
+        newVariable.counter = this.statementsLength;
+
+        return newVariable;
+    }
+
+    private Number transformNumber(parser.Number number) @nogc
+    {
+        return defaultAllocator.make!Number(number.value);
+    }
+
+    override Operand visit(parser.Statement statement) @nogc
+    {
         if ((cast(parser.BangStatement) statement) !is null)
         {
-        return transformExpression((cast(parser.BangStatement) statement).expression, statements, constants);
+            return (cast(parser.BangStatement) statement).accept(this);
+        }
+        assert(false, "Invalid statement type");
     }
-    return null;
-}
 
-HashTable!(String, int) transformConstants(ref Array!(parser.Definition) definitions) @nogc
+    private HashTable!(String, int) transformConstants(ref Array!(parser.Definition) definitions) @nogc
-{
+    {
         typeof(return) constants;
 
         foreach (definition; definitions[])
@@ -115,30 +216,5 @@ HashTable!(String, int) transformConstants(ref Array!(parser.Definition) definit
         }
 
         return constants;
-}
-
-Array!VariableDeclaration transformVariableDeclarations(ref Array!(parser.VariableDeclaration) variableDeclarations)
-@nogc
-{
-    typeof(return) variables;
-
-    foreach (ref variableDeclaration; variableDeclarations)
-    {
-        auto newDeclaration = MmapPool.instance.make!VariableDeclaration;
-        newDeclaration.identifier = variableDeclaration.identifier;
-        variables.insertBack(newDeclaration);
     }
-
-    return variables;
-}
-
-Definition transform(parser.Block block) @nogc
-{
-    auto target = MmapPool.instance.make!Definition;
-    auto constants = transformConstants(block.definitions);
-
-    transformStatement(block.statement, target.statements, constants);
-    target.variableDeclarations = transformVariableDeclarations(block.variableDeclarations);
-
-    return target;
 }

source/elna/lexer.d

@@ -7,30 +7,30 @@ import elna.result;
 import std.range;
 import tanya.container.array;
 import tanya.container.string;
-import tanya.memory.mmappool;
 
+extern(C++, "elna")
 struct Token
 {
-    enum Type
+    enum Type : ushort
     {
-        number,
+        number = 0,
-        subroutine, // Operator.
+        operator = 1,
-        let,
+        let = 2,
-        identifier,
+        identifier = 3,
-        equals,
+        equals = 4,
-        var,
+        var = 5,
-        semicolon,
+        semicolon = 6,
-        leftParen,
+        leftParen = 7,
-        rightParen,
+        rightParen = 8,
-        bang,
+        bang = 9,
-        dot,
+        dot = 10,
-        comma,
+        comma = 11,
     }
 
     union Value
     {
         int number;
-        String identifier;
+        const(char)* identifier;
     }
 
     private Type type;
@@ -39,62 +39,21 @@ struct Token
 
     @disable this();
 
-    this(Type type, Position position) @nogc nothrow pure @safe
+    this(Type type, Position position) @nogc nothrow pure @safe;
-    {
+    this(Type type, int value, Position position) @nogc nothrow pure @trusted;
-        this.type = type;
+    this(Type type, const(char)* value, Position position) @nogc nothrow;
-        this.position_ = position;
-    }
-
-    this(Type type, int value, Position position) @nogc nothrow pure @trusted
-    in (type == Type.number)
-    {
-        this(type, position);
-        this.value_.number = value;
-    }
-
-    this()(Type type, auto ref String value, Position position)
-    @nogc nothrow pure @trusted
-    in (type == Type.identifier)
-    {
-        this(type, position);
-        this.value_.identifier = value;
-    }
 
     /**
-     * Params:
+     * Returns: Expected token type.
-     *   type = Expected type.
-     *
-     * Returns: Whether this token is of the expected type.
      */
-    bool ofType(Type type) const @nogc nothrow pure @safe
+    Type of() const @nogc nothrow pure @safe;
-    {
+    const(char)* identifier() const @nogc nothrow pure;
-        return this.type == type;
+    int number() const @nogc nothrow pure;
-    }
-
-    @property auto value(Type type)() @nogc nothrow pure @trusted
-    in (ofType(type))
-    {
-        static if (type == Type.number)
-        {
-            return this.value_.number;
-        }
-        else static if (type == Type.identifier)
-        {
-            return this.value_.identifier;
-        }
-        else
-        {
-            static assert(false, "This type doesn't have a value");
-        }
-    }
 
     /**
      * Returns: The token position in the source text.
      */
-    @property const(Position) position() const @nogc nothrow pure @safe
+    @property const(Position) position() const @nogc nothrow pure @safe;
-    {
-        return this.position_;
-    }
 }
 
 /**
@@ -102,10 +61,10 @@ struct Token
  */
 struct Source
 {
-    char[] buffer;
+    const(char)* buffer;
     Position position;
 
-    this(char[] buffer) @nogc nothrow pure @safe
+    this(const(char)* buffer) @nogc nothrow pure @safe
     {
         this.buffer = buffer;
     }
@@ -114,7 +73,7 @@ struct Source
 
     bool empty() @nogc nothrow pure @safe
     {
-        return this.length == 0;
+        return this.buffer is null || this.buffer[0] == '\0';
     }
 
     char front() @nogc nothrow pure @safe
@@ -123,130 +82,36 @@ struct Source
         return this.buffer[0];
     }
 
-    void popFront() @nogc nothrow pure @safe
+    void popFront() @nogc nothrow pure
     in (!empty)
     {
-        this.buffer = buffer[1 .. $];
+        ++this.buffer;
         ++this.position.column;
     }
 
-    void breakLine() @nogc nothrow pure @safe
+    void breakLine() @nogc nothrow pure
     in (!empty)
     {
-        this.buffer = buffer[1 .. $];
+        ++this.buffer;
         ++this.position.line;
         this.position.column = 1;
     }
 
-    @property size_t length() const @nogc nothrow pure @safe
+    @property size_t length() const @nogc nothrow pure
     {
-        return this.buffer.length;
+        return strlen(this.buffer);
     }
 
-    char opIndex(size_t index) @nogc nothrow pure @safe
+    char opIndex(size_t index) @nogc nothrow pure
-    in (index < length)
     {
         return this.buffer[index];
     }
 
-    char[] opSlice(size_t i, size_t j) @nogc nothrow pure @safe
+    const(char)[] opSlice(size_t i, size_t j) @nogc nothrow pure
-    in
-    {
-        assert(i <= j);
-        assert(j <= length);
-    }
-    do
     {
         return this.buffer[i .. j];
     }
 }
 
-Array!Token lex(char[] buffer) @nogc
+extern(C++, "elna")
-{
+Token* lex(const(char)* buffer, CompileError* compileError, size_t* length) @nogc;
-    Array!Token tokens;
-    auto source = Source(buffer);
-
-    while (!source.empty)
-    {
-        if (source.front == ' ')
-        {
-            source.popFront;
-        }
-        else if (source.front >= '0' && source.front <= '9') // Multi-digit.
-        {
-            tokens.insertBack(Token(Token.Type.number, source.front - '0', source.position));
-            source.popFront;
-        }
-        else if (source.front == '=')
-        {
-            tokens.insertBack(Token(Token.Type.equals, source.position));
-            source.popFront;
-        }
-        else if (source.front == '(')
-        {
-            tokens.insertBack(Token(Token.Type.leftParen, source.position));
-            source.popFront;
-        }
-        else if (source.front == ')')
-        {
-            tokens.insertBack(Token(Token.Type.rightParen, source.position));
-            source.popFront;
-        }
-        else if (source.front == ';')
-        {
-            tokens.insertBack(Token(Token.Type.semicolon, source.position));
-            source.popFront;
-        }
-        else if (source.front == ',')
-        {
-            tokens.insertBack(Token(Token.Type.comma, source.position));
-            source.popFront;
-        }
-        else if (source.front == '!')
-        {
-            tokens.insertBack(Token(Token.Type.bang, source.position));
-            source.popFront;
-        }
-        else if (source.front == '.')
-        {
-            tokens.insertBack(Token(Token.Type.dot, source.position));
-            source.popFront;
-        }
-        else if (isalpha(source.front))
-        {
-            size_t i = 1;
-            while (i < source.length && isalpha(source[i]))
-            {
-                ++i;
-            }
-            if (source[0 .. i] == "const")
-            {
-                tokens.insertBack(Token(Token.Type.let, source.position));
-            }
-            else if (source[0 .. i] == "var")
-            {
-                tokens.insertBack(Token(Token.Type.var, source.position));
-            }
-            else
-            {
-                auto identifier = String(source[0 .. i]);
-                tokens.insertBack(Token(Token.Type.identifier, identifier, source.position));
-            }
-            source.popFrontN(i);
-        }
-        else if (source.front == '+') // Multi-character, random special characters.
-        {
-            tokens.insertBack(Token(Token.Type.subroutine, source.position));
-            source.popFront;
-        }
-        else if (source.front == '\n')
-        {
-            source.breakLine;
-        }
-        else
-        {
-            return typeof(tokens)(); // Error.
-        }
-    }
-    return tokens;
-}

source/elna/parser.d

@@ -1,106 +1,165 @@
 module elna.parser;
 
+import core.stdc.string;
 import elna.lexer;
 import elna.result;
 import tanya.container.array;
 import tanya.container.string;
 import tanya.memory.allocator;
-import tanya.memory.mmappool;
+import std.array;
+
+/**
+ * Parser visitor.
+ */
+interface ParserVisitor(Mapping)
+{
+    Mapping.Node visit(Node) @nogc;
+    Mapping.Definition visit(Definition) @nogc;
+    Mapping.Statement visit(Statement) @nogc;
+    Mapping.BangStatement visit(BangStatement) @nogc;
+    Mapping.Block visit(Block) @nogc;
+    Mapping.Expression visit(Expression) @nogc;
+    Mapping.Number visit(Number) @nogc;
+    Mapping.Variable visit(Variable) @nogc;
+    Mapping.BinaryExpression visit(BinaryExpression) @nogc;
+}
+
+/**
+ * AST node.
+ */
+abstract class Node
+{
+    Mapping.Node accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
+}
 
 /**
  * Constant definition.
  */
-class Definition
+class Definition : Node
 {
     Number number;
     String identifier;
+
+    Mapping.Definition accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
-/**
+abstract class Statement : Node
- * Variable declaration.
- */
-class VariableDeclaration
-{
-    String identifier;
-}
-
-abstract class Statement
 {
+    Mapping.Statement accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
 class BangStatement : Statement
 {
     Expression expression;
+
+    Mapping.BangStatement accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
-class Block
+class Block : Node
 {
     Array!Definition definitions;
-    Array!VariableDeclaration variableDeclarations;
     Statement statement;
+
+    Mapping.Block accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
-abstract class Expression
+abstract class Expression : Node
 {
+    Mapping.Expression accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
 class Number : Expression
 {
     int value;
+
+    Mapping.Number accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
 class Variable : Expression
 {
     String identifier;
+
+    Mapping.Variable accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
-class Subroutine : Expression
+extern(C++, "elna")
+enum BinaryOperator
+{
+    sum,
+    subtraction
+}
+
+class BinaryExpression : Expression
 {
     Expression lhs, rhs;
+    BinaryOperator operator;
+
+    this(Expression lhs, Expression rhs, String operator) @nogc
+    {
+        this.lhs = lhs;
+        this.rhs = rhs;
+        if (operator == "+")
+        {
+            this.operator = BinaryOperator.sum;
+        }
+        else if (operator == "-")
+        {
+            this.operator = BinaryOperator.subtraction;
+        }
+        else
+        {
+            assert(false, "Invalid binary operator");
+        }
+    }
+
+    Mapping.BinaryExpression accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
+    {
+        return visitor.visit(this);
+    }
 }
 
-private Result!Expression parseExpression(ref Array!(Token).Range tokens) @nogc
+private Result!Expression parseFactor(ref Token[] tokens) @nogc
-in (!tokens.empty, "Expected expression, got end of stream")
+in (!tokens.empty, "Expected factor, got end of stream")
 {
-    if (tokens.front.ofType(Token.Type.number))
+    if (tokens.front.of() == Token.Type.identifier)
     {
-        auto number = MmapPool.instance.make!Number;
+        auto variable = defaultAllocator.make!Variable;
-        number.value = tokens.front.value!(Token.Type.number);
+        variable.identifier = tokens.front.identifier()[0 .. strlen(tokens.front.identifier())];
-        tokens.popFront;
-        return Result!Expression(number);
-    }
-    else if (tokens.front.ofType(Token.Type.identifier))
-    {
-        auto variable = MmapPool.instance.make!Variable;
-        variable.identifier = tokens.front.value!(Token.Type.identifier);
         tokens.popFront;
         return Result!Expression(variable);
     }
-    else if (tokens.front.ofType(Token.Type.subroutine))
+    else if (tokens.front.of() == Token.Type.number)
     {
-        auto subroutine = MmapPool.instance.make!Subroutine;
+        auto number = defaultAllocator.make!Number;
+        number.value = tokens.front.number();
         tokens.popFront;
-        auto expression = parseExpression(tokens);
+        return Result!Expression(number);
-        if (expression.valid)
-        {
-            subroutine.lhs = expression.result;
     }
-        else
+    else if (tokens.front.of() == Token.Type.leftParen)
-        {
-            return Result!Expression("Expected left-hand side to be an expression", tokens.front.position);
-        }
-        expression = parseExpression(tokens);
-        if (expression.valid)
-        {
-            subroutine.rhs = expression.result;
-        }
-        else
-        {
-            return Result!Expression("Expected left-hand side to be an expression", tokens.front.position);
-        }
-        return Result!Expression(subroutine);
-    }
-    else if (tokens.front.ofType(Token.Type.leftParen))
     {
         tokens.popFront;
 
@@ -109,22 +168,53 @@ in (!tokens.empty, "Expected expression, got end of stream")
         tokens.popFront;
         return expression;
     }
-    return Result!Expression("Expected an expression", tokens.front.position);
+    return Result!Expression("Expected a factor", tokens.front.position);
 }
 
-private Result!Definition parseDefinition(ref Array!Token.Range tokens) @nogc
+private Result!Expression parseTerm(ref Token[] tokens) @nogc
+{
+    return parseFactor(tokens);
+}
+
+private Result!Expression parseExpression(ref Token[] tokens) @nogc
+in (!tokens.empty, "Expected expression, got end of stream")
+{
+    auto term = parseTerm(tokens);
+    if (!term.valid || tokens.empty || tokens.front.of() != Token.Type.operator)
+    {
+        return term;
+    }
+    auto operator = String(tokens.front.identifier()[0 .. strlen(tokens.front.identifier())]);
+    tokens.popFront;
+
+    auto expression = parseExpression(tokens);
+
+    if (expression.valid)
+    {
+        auto binaryExpression = defaultAllocator
+            .make!BinaryExpression(term.result, expression.result, operator);
+
+        return Result!Expression(binaryExpression);
+    }
+    else
+    {
+        return Result!Expression("Expected right-hand side to be an expression", tokens.front.position);
+    }
+}
+
+private Result!Definition parseDefinition(ref Token[] tokens) @nogc
 in (!tokens.empty, "Expected definition, got end of stream")
 {
-    auto definition = MmapPool.instance.make!Definition;
+    auto definition = defaultAllocator.make!Definition;
-    definition.identifier = tokens.front.value!(Token.Type.identifier); // Copy.
+    definition.identifier = tokens.front.identifier()[0 .. strlen(tokens.front.identifier())]; // Copy.
 
     tokens.popFront();
     tokens.popFront(); // Skip the equals sign.
 
-    if (tokens.front.ofType(Token.Type.number))
+    if (tokens.front.of() == Token.Type.number)
     {
-        auto number = MmapPool.instance.make!Number;
+        auto number = defaultAllocator.make!Number;
-        number.value = tokens.front.value!(Token.Type.number);
+        number.value = tokens.front.number();
         definition.number = number;
         tokens.popFront;
         return Result!Definition(definition);
@@ -132,13 +222,13 @@ in (!tokens.empty, "Expected definition, got end of stream")
     return Result!Definition("Expected a number", tokens.front.position);
 }
 
-private Result!Statement parseStatement(ref Array!Token.Range tokens) @nogc
+private Result!Statement parseStatement(ref Token[] tokens) @nogc
 in (!tokens.empty, "Expected block, got end of stream")
 {
-    if (tokens.front.ofType(Token.Type.bang))
+    if (tokens.front.of() == Token.Type.bang)
     {
         tokens.popFront;
-        auto statement = MmapPool.instance.make!BangStatement;
+        auto statement = defaultAllocator.make!BangStatement;
         auto expression = parseExpression(tokens);
         if (expression.valid)
         {
@@ -153,7 +243,7 @@ in (!tokens.empty, "Expected block, got end of stream")
     return Result!Statement("Expected ! statement", tokens.front.position);
 }
 
-private Result!(Array!Definition) parseDefinitions(ref Array!Token.Range tokens) @nogc
+private Result!(Array!Definition) parseDefinitions(ref Token[] tokens) @nogc
 in (!tokens.empty, "Expected definition, got end of stream")
 {
     tokens.popFront; // Skip const.
@@ -168,11 +258,11 @@ in (!tokens.empty, "Expected definition, got end of stream")
             return typeof(return)(definition.error.get);
         }
         definitions.insertBack(definition.result);
-        if (tokens.front.ofType(Token.Type.semicolon))
+        if (tokens.front.of() == Token.Type.semicolon)
         {
             break;
         }
-        if (tokens.front.ofType(Token.Type.comma))
+        if (tokens.front.of() == Token.Type.comma)
         {
             tokens.popFront;
         }
@@ -181,49 +271,11 @@ in (!tokens.empty, "Expected definition, got end of stream")
     return typeof(return)(definitions);
 }
 
-private Result!(Array!VariableDeclaration) parseVariableDeclarations(ref Array!Token.Range tokens) @nogc
+private Result!Block parseBlock(ref Token[] tokens) @nogc
-in (!tokens.empty, "Expected variable declarations, got end of stream")
-{
-    tokens.popFront; // Skip var.
-
-    Array!VariableDeclaration variableDeclarations;
-
-    while (!tokens.empty)
-    {
-        auto currentToken = tokens.front;
-        if (currentToken.ofType(Token.Type.identifier))
-        {
-            auto variableDeclaration = MmapPool.instance.make!VariableDeclaration;
-            variableDeclaration.identifier = currentToken.value!(Token.Type.identifier);
-            variableDeclarations.insertBack(variableDeclaration);
-            tokens.popFront;
-        }
-        else
-        {
-            return typeof(return)("Expected variable name", tokens.front.position);
-        }
-        if (tokens.empty)
-        {
-            return typeof(return)("Expected \";\" or \",\" name", currentToken.position);
-        }
-        if (tokens.front.ofType(Token.Type.semicolon))
-        {
-            break;
-        }
-        if (tokens.front.ofType(Token.Type.comma))
-        {
-            tokens.popFront;
-        }
-    }
-
-    return typeof(return)(variableDeclarations);
-}
-
-private Result!Block parseBlock(ref Array!Token.Range tokens) @nogc
 in (!tokens.empty, "Expected block, got end of stream")
 {
-    auto block = MmapPool.instance.make!Block;
+    auto block = defaultAllocator.make!Block;
-    if (tokens.front.ofType(Token.Type.let))
+    if (tokens.front.of() == Token.Type.let)
     {
         auto constDefinitions = parseDefinitions(tokens);
         if (constDefinitions.valid)
@@ -236,19 +288,6 @@ in (!tokens.empty, "Expected block, got end of stream")
         }
         tokens.popFront;
     }
-    if (tokens.front.ofType(Token.Type.var))
-    {
-        auto variableDeclarations = parseVariableDeclarations(tokens);
-        if (variableDeclarations.valid)
-        {
-            block.variableDeclarations = variableDeclarations.result;
-        }
-        else
-        {
-            return Result!Block(variableDeclarations.error.get);
-        }
-        tokens.popFront;
-    }
     auto statement = parseStatement(tokens);
     if (statement.valid)
     {
@@ -262,7 +301,7 @@ in (!tokens.empty, "Expected block, got end of stream")
     return Result!Block(block);
 }
 
-Result!Block parse(ref Array!Token tokenStream) @nogc
+Result!Block parse(Token[] tokenStream) @nogc
 {
     auto tokens = tokenStream[];
     return parseBlock(tokens);

source/elna/result.d

@@ -1,10 +1,13 @@
 module elna.result;
 
 import std.typecons;
+import tanya.container.array;
+import tanya.container.string;
 
 /**
  * Position in the source text.
  */
+extern(C++, "elna")
 struct Position
 {
     /// Line.
@@ -14,9 +17,10 @@ struct Position
     size_t column = 1;
 }
 
+extern(C++, "elna")
 struct CompileError
 {
-    private string message_;
+    private const(char)* message_;
 
     private Position position_;
 
@@ -27,29 +31,16 @@ struct CompileError
      *   message = Error text.
      *   position = Error position in the source text.
      */
-    this(string message, Position position) @nogc nothrow pure @safe
+    this(const(char)* message, const Position position) @nogc nothrow pure @safe;
-    {
-        this.message_ = message;
-        this.position_ = position;
-    }
 
     /// Error text.
-    @property string message() const @nogc nothrow pure @safe
+    @property const(char)* what() const @nogc nothrow pure @safe;
-    {
-        return this.message_;
-    }
 
     /// Error line in the source text.
-    @property size_t line() const @nogc nothrow pure @safe
+    @property size_t line() const @nogc nothrow pure @safe;
-    {
-        return this.position_.line;
-    }
 
     /// Error column in the source text.
-    @property size_t column() const @nogc nothrow pure @safe
+    @property size_t column() const @nogc nothrow pure @safe;
-    {
-        return this.position_.column;
-    }
 }
 
 struct Result(T)
@@ -63,7 +54,7 @@ struct Result(T)
         this.error = typeof(this.error).init;
     }
 
-    this(string message, Position position)
+    this(const(char)* message, Position position)
     {
         this.result = T.init;
         this.error = CompileError(message, position);
@@ -82,3 +73,26 @@ struct Result(T)
         return error.isNull;
     }
 }
+
+extern(C++, "elna")
+enum Target
+{
+    text,
+    high20,
+    lower12i
+}
+
+extern(C++, "elna")
+struct Reference
+{
+    const(char)* name;
+    size_t offset;
+    Target target;
+}
+
+struct Symbol
+{
+    String name;
+    Array!ubyte text;
+    Array!Reference symbols;
+}

source/elna/riscv.d

@@ -0,0 +1,183 @@
+module elna.riscv;
+
+import core.stdc.stdlib;
+import elna.ir;
+import elna.result;
+import tanya.container.array;
+import tanya.container.string;
+
+extern(C++, "elna")
+enum XRegister : ubyte
+{
+    zero = 0,
+    ra = 1,
+    sp = 2,
+    gp = 3,
+    tp = 4,
+    t0 = 5,
+    t1 = 6,
+    t2 = 7,
+    s0 = 8,
+    s1 = 9,
+    a0 = 10,
+    a1 = 11,
+    a2 = 12,
+    a3 = 13,
+    a4 = 14,
+    a5 = 15,
+    a6 = 16,
+    a7 = 17,
+    s2 = 18,
+    s3 = 19,
+    s4 = 20,
+    s5 = 21,
+    s6 = 22,
+    s7 = 23,
+    s8 = 24,
+    s9 = 25,
+    s10 = 26,
+    s11 = 27,
+    t3 = 28,
+    t4 = 29,
+    t5 = 30,
+    t6 = 31,
+}
+
+extern(C++, "elna")
+enum Funct3 : ubyte
+{
+    addi = 0b000,
+    slti = 0b001,
+    sltiu = 0b011,
+    andi = 0b111,
+    ori = 0b110,
+    xori = 0b100,
+    slli = 0b000,
+    srli = 0b101,
+    srai = 0b101,
+    add = 0b000,
+    slt = 0b010,
+    sltu = 0b011,
+    and = 0b111,
+    or = 0b110,
+    xor = 0b100,
+    sll = 0b001,
+    srl = 0b101,
+    sub = 0b000,
+    sra = 0b101,
+    beq = 0b000,
+    bne = 0b001,
+    blt = 0b100,
+    bltu = 0b110,
+    bge = 0b101,
+    bgeu = 0b111,
+    fence = 0b000,
+    fenceI = 0b001,
+    csrrw = 0b001,
+    csrrs = 0b010,
+    csrrc = 0b011,
+    csrrwi = 0b101,
+    csrrsi = 0b110,
+    csrrci = 0b111,
+    priv = 0b000,
+    sb = 0b000,
+    sh = 0b001,
+    sw = 0b010,
+    lb = 0b000,
+    lh = 0b001,
+    lw = 0b010,
+    lbu = 0b100,
+    lhu = 0b101,
+    jalr = 0b000,
+}
+
+extern(C++, "elna")
+enum Funct12 : ubyte
+{
+    ecall = 0b000000000000,
+    ebreak = 0b000000000001,
+}
+
+extern(C++, "elna")
+enum Funct7 : ubyte
+{
+    none = 0,
+    sub = 0b0100000
+}
+
+extern(C++, "elna")
+enum BaseOpcode : ubyte
+{
+    opImm = 0b0010011,
+    lui = 0b0110111,
+    auipc = 0b0010111,
+    op = 0b0110011,
+    jal = 0b1101111,
+    jalr = 0b1100111,
+    branch = 0b1100011,
+    load = 0b0000011,
+    store = 0b0100011,
+    miscMem = 0b0001111,
+    system = 0b1110011,
+}
+
+extern(C++, "elna")
+struct Instruction
+{
+    private uint instruction;
+
+    this(BaseOpcode opcode) @nogc;
+    @disable this();
+
+    ref Instruction i(XRegister rd, Funct3 funct3, XRegister rs1, uint immediate)
+    return scope @nogc;
+
+    ref Instruction s(uint imm1, Funct3 funct3, XRegister rs1, XRegister rs2)
+    return scope @nogc;
+
+    ref Instruction r(XRegister rd, Funct3 funct3, XRegister rs1, XRegister rs2, Funct7 funct7 = Funct7.none)
+    return scope @nogc;
+
+    ref Instruction u(XRegister rd, uint imm)
+    return scope @nogc;
+
+    ubyte* encode() return scope @nogc;
+}
+
+extern(C++, "elna")
+class RiscVVisitor : IRVisitor
+{
+    Instruction *instructions;
+    size_t instructionsLength;
+    bool registerInUse;
+    uint variableCounter = 1;
+    Reference[3] references;
+
+    override void visit(Node) @nogc;
+    override void visit(Definition definition) @nogc;
+    override void visit(Operand operand) @nogc;
+    override void visit(Variable variable) @nogc;
+    override void visit(Number number) @nogc;
+    override void visit(BinaryExpression expression) @nogc;
+}
+
+Symbol writeNext(Definition ast) @nogc
+{
+    Array!Instruction instructions;
+    auto visitor = cast(RiscVVisitor) malloc(__traits(classInstanceSize, RiscVVisitor));
+    (cast(void*) visitor)[0 .. __traits(classInstanceSize, RiscVVisitor)] = __traits(initSymbol, RiscVVisitor)[];
+    scope (exit)
+    {
+        free(cast(void*) visitor);
+    }
+    visitor.visit(ast);
+
+    auto program = Symbol(String("main"));
+
+    program.symbols = Array!Reference(visitor.references[]);
+    foreach (ref instruction; visitor.instructions[0 .. visitor.instructionsLength])
+    {
+        program.text.insertBack(instruction.encode[0 .. uint.sizeof]);
+    }
+    return program;
+}

source/ir.cpp

@@ -0,0 +1,53 @@
+#include "elna/ir.hpp"
+
+namespace elna::ir
+{
+    /**
+     * AST node.
+     */
+    void Node::accept(IRVisitor *)
+    {
+    }
+
+    void Definition::accept(IRVisitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    void Operand::accept(IRVisitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    void Number::accept(IRVisitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    void Variable::accept(IRVisitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    BinaryExpression::BinaryExpression(Operand *lhs, Operand *rhs, BinaryOperator _operator)
+    {
+        this->lhs = lhs;
+        this->rhs = rhs;
+        this->_operator = _operator;
+    }
+
+    void BinaryExpression::accept(IRVisitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    BangExpression::BangExpression(Operand *operand)
+    {
+        this->operand = operand;
+    }
+
+    void BangExpression::accept(IRVisitor *visitor)
+    {
+        visitor->visit(this);
+    }
+}

source/lexer.cpp

@@ -0,0 +1,270 @@
+#include "elna/lexer.hpp"
+
+namespace elna
+{
+    source::source(const std::string& buffer)
+        : m_buffer(buffer)
+    {
+    }
+
+    source::const_iterator source::begin() const
+    {
+        return source::const_iterator(std::cbegin(m_buffer));
+    }
+
+    source::const_iterator source::end() const
+    {
+        Position end_position{ 0, 0 };
+
+        return source::const_iterator(std::cend(m_buffer), end_position);
+    }
+
+    source::const_iterator::const_iterator(std::string::const_iterator buffer,
+            const Position start_position)
+        : m_buffer(buffer), m_position(start_position)
+    {
+    }
+
+    const Position& source::const_iterator::position() const noexcept
+    {
+        return this->m_position;
+    }
+
+    source::const_iterator::reference source::const_iterator::operator*() const noexcept
+    {
+        return *m_buffer;
+    }
+
+    source::const_iterator::pointer source::const_iterator::operator->() const noexcept
+    {
+        return m_buffer.base();
+    }
+
+    source::const_iterator& source::const_iterator::operator++()
+    {
+        if (*this->m_buffer == '\n')
+        {
+            this->m_position.column = 1;
+            ++this->m_position.line;
+        }
+        else
+        {
+            ++this->m_position.column;
+        }
+        std::advance(this->m_buffer, 1);
+
+        return *this;
+    }
+
+    source::const_iterator& source::const_iterator::operator++(int)
+    {
+        auto tmp = *this;
+        ++(*this);
+        return *this;
+    }
+
+    bool source::const_iterator::operator==(const source::const_iterator& that) const noexcept
+    {
+        return this->m_buffer == that.m_buffer;
+    }
+
+    bool source::const_iterator::operator!=(const source::const_iterator& that) const noexcept
+    {
+        return !(*this == that);
+    }
+
+    Token::Token(const Type of, const char *value, Position position)
+        : m_type(of), m_position(position)
+    {
+        std::size_t value_length = strlen(value);
+        char *buffer = reinterpret_cast<char *>(malloc(value_length + 1));
+
+        std::memcpy(buffer, value, value_length);
+        buffer[value_length] = 0;
+
+        m_value.identifier = buffer;
+    }
+
+    Token::Token(const Type of, std::int32_t number, Position position)
+        : m_type(of), m_position(position)
+    {
+        m_value.number = number;
+    }
+
+    Token::Token(const Type of, Position position)
+        : m_type(of), m_position(position)
+    {
+    }
+
+    Token::Token(const Token& that)
+        : m_type(that.of()), m_position(that.position())
+    {
+        *this = that;
+    }
+
+    Token::Token(Token&& that)
+        : m_type(that.of()), m_position(that.position())
+    {
+        *this = std::move(that);
+    }
+
+    Token::~Token()
+    {
+        if (m_type == TOKEN_IDENTIFIER || m_type == TOKEN_OPERATOR)
+        {
+            std::free(const_cast<char*>(m_value.identifier));
+        }
+    }
+
+    Token& Token::operator=(const Token& that)
+    {
+        m_type = that.of();
+        m_position = that.position();
+        if (that.of() == TOKEN_IDENTIFIER || that.of() == TOKEN_OPERATOR)
+        {
+            std::size_t value_length = strlen(that.identifier());
+            char *buffer = reinterpret_cast<char *>(malloc(value_length + 1));
+
+            std::memcpy(buffer, that.identifier(), value_length);
+            buffer[value_length] = 0;
+
+            m_value.identifier = buffer;
+        }
+        else if (that.of() == TOKEN_NUMBER)
+        {
+            m_value.number = that.number();
+        }
+        return *this;
+    }
+
+    Token& Token::operator=(Token&& that)
+    {
+        m_type = that.of();
+        m_position = that.position();
+        if (that.of() == TOKEN_IDENTIFIER || that.of() == TOKEN_OPERATOR)
+        {
+            m_value.identifier = that.identifier();
+            that.m_value.identifier = nullptr;
+        }
+        else if (that.of() == TOKEN_NUMBER)
+        {
+            m_value.number = that.number();
+        }
+        return *this;
+    }
+
+    Token::Type Token::of() const noexcept
+    {
+        return m_type;
+    }
+
+    const char *Token::identifier() const noexcept
+    {
+        return m_value.identifier;
+    }
+
+    std::int32_t Token::number() const noexcept
+    {
+        return m_value.number;
+    }
+
+    const Position& Token::position() const noexcept
+    {
+        return m_position;
+    }
+
+    Token *lex(const char *buffer, CompileError *compile_error, std::size_t *length)
+    {
+        std::vector<Token> tokens;
+        source input{ buffer };
+
+        for (auto iterator = input.begin(); iterator != input.end();)
+        {
+            if (*iterator == ' ' || *iterator == '\n')
+            {
+            }
+            else if (std::isdigit(*iterator))
+            {
+                tokens.emplace_back(
+                        Token::TOKEN_NUMBER,
+                        static_cast<std::int32_t>(*iterator - '0'),
+                        iterator.position()
+                );
+            }
+            else if (*iterator == '=')
+            {
+                tokens.emplace_back(Token::TOKEN_EQUALS, iterator.position());
+            }
+            else if (*iterator == '(')
+            {
+                tokens.emplace_back(Token::TOKEN_LEFT_PAREN, iterator.position());
+            }
+            else if (*iterator == ')')
+            {
+                tokens.emplace_back(Token::TOKEN_RIGHT_PAREN, iterator.position());
+            }
+            else if (*iterator == ';')
+            {
+                tokens.emplace_back(Token::TOKEN_SEMICOLON, iterator.position());
+            }
+            else if (*iterator == ',')
+            {
+                tokens.emplace_back(Token::TOKEN_COMMA, iterator.position());
+            }
+            else if (*iterator == '!')
+            {
+                tokens.emplace_back(Token::TOKEN_BANG, iterator.position());
+            }
+            else if (*iterator == '.')
+            {
+                tokens.emplace_back(Token::TOKEN_DOT, iterator.position());
+            }
+            else if (std::isalpha(*iterator))
+            {
+                std::string word;
+                auto i = iterator;
+                while (i != input.end() && std::isalpha(*i))
+                {
+                    word.push_back(*i);
+                    ++i;
+                }
+                if (word == "const")
+                {
+                    tokens.emplace_back(Token::TOKEN_LET, iterator.position());
+                }
+                else if (word == "var")
+                {
+                    tokens.emplace_back(Token::TOKEN_VAR, iterator.position());
+                }
+                else
+                {
+                    tokens.emplace_back(Token::TOKEN_IDENTIFIER, word.c_str(), iterator.position());
+                }
+                iterator = i;
+                continue;
+            }
+            else if (*iterator == '+' || *iterator == '-')
+            {
+                std::string _operator{ *iterator };
+
+                tokens.emplace_back(Token::TOKEN_OPERATOR, _operator.c_str(), iterator.position());
+            }
+            else
+            {
+                *compile_error = CompileError("Unexpected next character", iterator.position());
+                return nullptr;
+            }
+            ++iterator;
+        }
+        Token *target = reinterpret_cast<Token *>(malloc(tokens.size() * sizeof(Token) + sizeof(Token)));
+        int i = 0;
+        for (auto& token : tokens)
+        {
+            target[i] = std::move(token);
+            ++i;
+        }
+        *length = i;
+
+        return target;
+    }
+}

source/main.d

@@ -1,72 +1,33 @@
-import core.stdc.stdio;
+import elna.backend;
-import core.stdc.string;
-import core.stdc.stdlib;
-import elna.lexer;
-import elna.parser;
-import elna.generator;
 import elna.ir;
+import elna.arguments;
+import std.path;
+import std.sumtype;
 import tanya.container.string;
 import tanya.memory.allocator;
 import tanya.memory.mmappool;
 
-private char[] readSource(size_t N)(string source, out char[N] buffer) @nogc
-{
-    memcpy(buffer.ptr, source.ptr, source.length + 1);
-    buffer[source.length] = '\0';
-    auto handle = fopen(buffer.ptr, "r");
-    if (handle is null)
-    {
-        perror(buffer.ptr);
-        return null;
-    }
-    fseek(handle, 0, SEEK_END);
-    size_t fsize = ftell(handle);
-    rewind(handle);
-
-    fread(buffer.ptr, fsize, 1, handle);
-    fclose(handle);
-    buffer[fsize] = '\0';
-
-    return buffer[0 .. fsize];
-}
-
 int main(string[] args)
 {
-    char[255] buffer;
-
     defaultAllocator = MmapPool.instance;
 
-    if (args.length < 2)
+    return Arguments.parse(args).match!(
+        (ArgumentError argumentError) => 4,
+        (Arguments arguments) {
+            String outputFilename;
+            if (arguments.output is null)
             {
-        return 4;
+                outputFilename = arguments
+                    .inFile
+                    .baseName
+                    .withExtension("o");
             }
-    auto sourceText = readSource(args[1], buffer);
+            else
-    if (sourceText is null)
             {
-        return 3;
+                outputFilename = String(arguments.output);
             }
-    auto tokens = lex(sourceText);
-    if (tokens.length == 0)
-    {
-        printf("Lexical analysis failed.\n");
-        return 1;
-    }
-    auto ast = parse(tokens);
-    if (!ast.valid)
-    {
-        auto compileError = ast.error.get;
-        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.message.ptr);
-        return 2;
-    }
-    auto ir = transform(ast.result);
 
-    String outputFilename = String("build/");
+            return generate(arguments.inFile, outputFilename);
-    outputFilename.insertBack(args[1][0 .. $ - 4]);
+        }
-    outputFilename.insertBack("o");
+    );
-    writeObject(ir, outputFilename);
-
-    auto code = generate(ir);
-    printf("%s", code.toStringz());
-
-    return 0;
 }

source/result.cpp

@@ -0,0 +1,25 @@
+#include "elna/result.hpp"
+
+namespace elna
+{
+    CompileError::CompileError(const char *message, const Position position) noexcept
+    {
+        this->message = message;
+        this->position = position;
+    }
+
+    char const *CompileError::what() const noexcept
+    {
+        return this->message;
+    }
+
+    std::size_t CompileError::line() const noexcept
+    {
+        return this->position.line;
+    }
+
+    std::size_t CompileError::column() const noexcept
+    {
+        return this->position.column;
+    }
+}

source/riscv.cpp

@@ -0,0 +1,191 @@
+#include "elna/parser.hpp"
+#include "elna/riscv.hpp"
+#include <type_traits>
+
+namespace elna
+{
+    Instruction::Instruction(BaseOpcode opcode)
+    {
+        this->instruction = static_cast<std::underlying_type<BaseOpcode>::type>(opcode);
+    }
+
+    Instruction& Instruction::i(XRegister rd, Funct3 funct3, XRegister rs1, std::uint32_t immediate)
+    {
+        this->instruction |= (static_cast<std::underlying_type<XRegister>::type>(rd) << 7)
+            | (static_cast<std::underlying_type<Funct3>::type>(funct3) << 12)
+            | (static_cast<std::underlying_type<XRegister>::type>(rs1) << 15)
+            | (immediate << 20);
+
+        return *this;
+    }
+
+    Instruction& Instruction::s(std::uint32_t imm1, Funct3 funct3, XRegister rs1, XRegister rs2)
+    {
+        this->instruction |= ((imm1 & 0b11111) << 7)
+            | (static_cast<std::underlying_type<Funct3>::type>(funct3) << 12)
+            | (static_cast<std::underlying_type<XRegister>::type>(rs1) << 15)
+            | (static_cast<std::underlying_type<XRegister>::type>(rs2) << 20)
+            | ((imm1 & 0b111111100000) << 20);
+
+        return *this;
+    }
+
+    Instruction& Instruction::r(XRegister rd, Funct3 funct3, XRegister rs1, XRegister rs2, Funct7 funct7)
+    {
+        this->instruction |= (static_cast<std::underlying_type<XRegister>::type>(rd) << 7)
+            | (static_cast<std::underlying_type<Funct3>::type>(funct3) << 12)
+            | (static_cast<std::underlying_type<XRegister>::type>(rs1) << 15)
+            | (static_cast<std::underlying_type<XRegister>::type>(rs2) << 20)
+            | (static_cast<std::underlying_type<Funct7>::type>(funct7) << 25);
+
+        return *this;
+    }
+
+    Instruction& Instruction::u(XRegister rd, std::uint32_t imm)
+    {
+        this->instruction |= (static_cast<std::underlying_type<XRegister>::type>(rd) << 7) | (imm << 12);
+
+        return *this;
+    }
+
+    std::uint8_t *Instruction::encode()
+    {
+        return reinterpret_cast<std::uint8_t *>(&this->instruction);
+    }
+
+    void RiscVVisitor::visit(ir::Node *)
+    {
+    }
+
+    void RiscVVisitor::visit(ir::Definition *definition)
+    {
+        const uint stackSize = static_cast<std::uint32_t>(definition->statementsLength * 4 + 12);
+
+        this->instructionsLength += 4;
+        this->instructions = reinterpret_cast<Instruction *>(
+                realloc(this->instructions, this->instructionsLength * sizeof(Instruction)));
+
+        // Prologue.
+        this->instructions[instructionsLength - 4] = Instruction(BaseOpcode::opImm)
+            .i(XRegister::sp, Funct3::addi, XRegister::sp, -stackSize);
+        this->instructions[instructionsLength - 3] = Instruction(BaseOpcode::store)
+            .s(stackSize - 4, Funct3::sw, XRegister::sp, XRegister::s0);
+        this->instructions[instructionsLength - 2] = Instruction(BaseOpcode::store)
+            .s(stackSize - 8, Funct3::sw, XRegister::sp, XRegister::ra);
+        this->instructions[instructionsLength - 1] = Instruction(BaseOpcode::opImm)
+            .i(XRegister::s0, Funct3::addi, XRegister::sp, stackSize);
+
+        for (std::size_t i = 0; i < definition->statementsLength; ++i)
+        {
+            definition->statements[i]->accept(this);
+        }
+        this->registerInUse = true;
+        definition->result->accept(this);
+        this->registerInUse = false;
+
+        this->instructions = reinterpret_cast<Instruction*>(
+            realloc(this->instructions, (this->instructionsLength + 10) * sizeof(Instruction)));
+
+        // Print the result.
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::opImm)
+            .i(XRegister::a1, Funct3::addi, XRegister::a0, 0);
+        this->references[0] = Reference();
+        this->references[0].name = ".CL0";
+        this->references[0].offset = instructionsLength * 4;
+        this->references[0].target = Target::high20;
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::lui).u(XRegister::a5, 0);
+        this->references[1] = Reference();
+        this->references[1].name = ".CL0";
+        this->references[1].offset = instructionsLength * 4;
+        this->references[1].target = Target::lower12i;
+
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::opImm)
+            .i(XRegister::a0, Funct3::addi, XRegister::a5, 0);
+        this->references[2] = Reference();
+        this->references[2].name = "printf";
+        this->references[2].offset = instructionsLength * 4;
+        this->references[2].target = Target::text;
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::auipc).u(XRegister::ra, 0);
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::jalr)
+            .i(XRegister::ra, Funct3::jalr, XRegister::ra, 0);
+        // Set the return value (0).
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::op)
+            .r(XRegister::a0, Funct3::_and, XRegister::zero, XRegister::zero);
+
+        // Epilogue.
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::load)
+            .i(XRegister::s0, Funct3::lw, XRegister::sp, stackSize - 4);
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::load)
+            .i(XRegister::ra, Funct3::lw, XRegister::sp, stackSize - 8);
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::opImm)
+                .i(XRegister::sp, Funct3::addi, XRegister::sp, stackSize);
+        this->instructions[instructionsLength++] = Instruction(BaseOpcode::jalr)
+            .i(XRegister::zero, Funct3::jalr, XRegister::ra, 0);
+    }
+
+    void RiscVVisitor::visit(ir::Operand *operand)
+    {
+        if (dynamic_cast<ir::Variable *>(operand) != nullptr)
+        {
+            return dynamic_cast<ir::Variable *>(operand)->accept(this);
+        }
+        if (dynamic_cast<ir::Number *>(operand) != nullptr)
+        {
+            return dynamic_cast<ir::Number *>(operand)->accept(this);
+        }
+    }
+
+    void RiscVVisitor::visit(ir::Variable *variable)
+    {
+        const auto freeRegister = this->registerInUse ? XRegister::a0 : XRegister::t0;
+
+        ++this->instructionsLength;
+        this->instructions = reinterpret_cast<Instruction *>(
+                realloc(this->instructions, this->instructionsLength * sizeof(Instruction)));
+        // movl -x(%rbp), %eax; where x is a number.
+        this->instructions[instructionsLength - 1] = Instruction(BaseOpcode::load)
+            .i(freeRegister, Funct3::lw, XRegister::sp,
+                static_cast<std::int8_t>(variable->counter * 4));
+    }
+
+    void RiscVVisitor::visit(ir::Number *number)
+    {
+        const auto freeRegister = this->registerInUse ? XRegister::a0 : XRegister::t0;
+
+        ++this->instructionsLength;
+        this->instructions = reinterpret_cast<Instruction *>(
+                realloc(this->instructions, this->instructionsLength * sizeof(Instruction)));
+        this->instructions[this->instructionsLength - 1] =
+            Instruction(BaseOpcode::opImm) // movl $x, %eax; where $x is a number.
+                .i(freeRegister, Funct3::addi, XRegister::zero, number->value);
+    }
+
+    void RiscVVisitor::visit(ir::BinaryExpression *expression)
+    {
+        this->registerInUse = true;
+        expression->lhs->accept(this);
+        this->registerInUse = false;
+        expression->rhs->accept(this);
+
+        this->instructionsLength += 2;
+        this->instructions = reinterpret_cast<Instruction *>(
+                realloc(this->instructions, this->instructionsLength * sizeof(Instruction)));
+        // Calculate the result and assign it to a variable on the stack.
+        switch (expression->_operator)
+        {
+            case BinaryOperator::sum:
+                this->instructions[instructionsLength - 2] = Instruction(BaseOpcode::op)
+                    .r(XRegister::a0, Funct3::add, XRegister::a0, XRegister::t0);
+                break;
+            case BinaryOperator::subtraction:
+                this->instructions[instructionsLength - 2] = Instruction(BaseOpcode::op)
+                    .r(XRegister::a0, Funct3::sub, XRegister::a0, XRegister::t0, Funct7::sub);
+                break;
+        }
+        this->instructions[instructionsLength - 1] = // movl %eax, -x(%rbp); where x is a number.
+            Instruction(BaseOpcode::store)
+                .s(static_cast<std::uint32_t>(this->variableCounter * 4), Funct3::sw, XRegister::sp, XRegister::a0);
+
+        ++this->variableCounter;
+    }
+}

tests/7_member_sum.eln

@@ -0,0 +1 @@
+! 3 + 4 + 5 + 1 + 2 + 4 + 3

tests/const_list.eln

@@ -1,3 +1,3 @@
 const a = 1, b = 2;
-! + a b
+! a + b
 .

tests/expectations/7_member_sum.txt

@@ -0,0 +1 @@
+22

tests/expectations/left_nested_sum.txt

@@ -0,0 +1 @@
+8

tests/expectations/print_number.txt

@@ -0,0 +1 @@
+3

tests/expectations/subtraction.txt

@@ -0,0 +1 @@
+1

tests/left_nested_sum.eln

@@ -0,0 +1,2 @@
+! (3 + 4) + 1
+.

tests/print_number.eln

@@ -0,0 +1,2 @@
+! 3
+.

tests/runner.cpp

@@ -0,0 +1,151 @@
+#include <boost/process.hpp>
+
+#include <filesystem>
+#include <iostream>
+#include "elna/tester.hpp"
+
+namespace elna
+{
+    std::uint32_t test_results::total() const noexcept
+    {
+        return m_total;
+    }
+
+    std::uint32_t test_results::passed() const noexcept
+    {
+        return m_passed;
+    }
+
+    std::uint32_t test_results::failed() const noexcept
+    {
+        return m_total - m_passed;
+    }
+
+    int test_results::exit_code() const noexcept
+    {
+        return m_total == m_passed ? EXIT_SUCCESS : EXIT_FAILURE;
+    }
+
+    void test_results::add_exit_code(const int exit_code) noexcept
+    {
+        ++m_total;
+        if (exit_code == 0)
+        {
+            ++m_passed;
+        }
+    }
+
+    static std::string in_build_directory(const std::filesystem::path& path)
+    {
+        return "build/riscv" / path;
+    }
+
+    static int build_test(const std::filesystem::directory_entry& test_entry)
+    {
+        const std::filesystem::path test_filename = test_entry.path().filename();
+
+        std::filesystem::path test_binary = in_build_directory(test_filename);
+        std::filesystem::path test_object = test_binary;
+        test_binary.replace_extension();
+        test_object.replace_extension(".o");
+
+        std::filesystem::remove(test_binary);
+        std::filesystem::remove(test_object);
+
+        auto status = boost::process::system("./build/bin/elna",
+                "-o", test_object.string(), test_entry.path().string());
+        if (status != 0)
+        {
+            return status;
+        }
+        status = boost::process::system(
+                "/opt/riscv/bin/riscv32-unknown-elf-ld",
+                "-o", test_binary.string(),
+                "-L/opt/riscv/lib/gcc/riscv32-unknown-elf/13.2.0/",
+                "-L/opt/riscv/riscv32-unknown-elf/lib",
+                "/opt/riscv/riscv32-unknown-elf/lib/crt0.o",
+                "/opt/riscv/lib/gcc/riscv32-unknown-elf/13.2.0/crtbegin.o",
+               test_object.string(),
+                "--start-group", "-lgcc", "-lc", "-lgloss", "--end-group",
+                "/opt/riscv/lib/gcc/riscv32-unknown-elf/13.2.0/crtend.o"
+        );
+        return status;
+    }
+
+    static int run_test(const std::filesystem::directory_entry& test_entry)
+    {
+        const std::filesystem::path test_filename = test_entry.path().filename();
+
+        std::filesystem::path test_binary = in_build_directory(test_filename);
+        test_binary.replace_extension();
+
+        std::filesystem::path expectation_path = test_entry.path().parent_path() / "expectations" / test_filename;
+        expectation_path.replace_extension(".txt");
+
+        std::cout << "Running " << test_binary << std::endl;
+
+        boost::process::pipe pipe_stream;
+        boost::process::child vm(
+            "/opt/riscv/bin/spike", "--isa=RV32IMAC",
+            "/opt/riscv/riscv32-unknown-elf/bin/pk",
+            test_binary.string(),
+            boost::process::std_out > pipe_stream
+        );
+        boost::process::child diff(
+                "/usr/bin/diff", "-Nur", "--color",
+                expectation_path.string(), "-",
+                boost::process::std_in < pipe_stream
+        );
+        vm.wait();
+        diff.wait();
+
+        return diff.exit_code();
+    }
+
+    static test_results run_in_path(const std::filesystem::path test_directory)
+    {
+        test_results results;
+
+        for (const auto& test_entry : std::filesystem::directory_iterator(test_directory))
+        {
+            if (test_entry.path().extension() != ".eln" || !test_entry.is_regular_file())
+            {
+                continue;
+            }
+            int status{ 0 };
+
+            try
+            {
+                status = build_test(test_entry);
+            }
+            catch (const boost::process::process_error& exception)
+            {
+                std::cout << exception.what() << std::endl;
+                status = 3;
+                continue;
+            }
+            if (status == 0)
+            {
+                status = run_test(test_entry);
+            }
+            results.add_exit_code(status);
+        }
+        return results;
+    }
+};
+
+int main()
+{
+    boost::process::system("rake");
+
+    std::cout << "Run all tests and check the results" << std::endl;
+    std::filesystem::path test_directory{ "tests" };
+    const auto results = elna::run_in_path(test_directory);
+
+    std::cout << std::endl;
+    std::cout << results.total() << " tests run, "
+        << results.passed() << " passed, "
+        << results.failed() << " failed." << std::endl;
+
+    return results.exit_code();
+}

tests/subtraction.eln

@@ -0,0 +1,2 @@
+! 5 - 4
+.

tests/sum.eln

@@ -0,0 +1,2 @@
+! 1 + 7
+.

tests/sum.elna

@@ -1,2 +0,0 @@
-! + 1 7
-.

tests/sums.eln

@@ -0,0 +1,2 @@
+! 1 + (3 + 4)
+.

tests/sums.elna

@@ -1,2 +0,0 @@
-! + 1 (+ 3 4)
-.