Print test summary

CMakeLists.txt

@@ -12,11 +12,14 @@ 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
-	shell/result.cpp include/elna/result.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

@@ -4,87 +4,16 @@ require 'open3'
 
 DFLAGS = ['--warn-no-deprecated', '-L/usr/lib64/gcc-12']
 BINARY = 'build/bin/elna'
-TESTS = FileList['tests/*.eln'].flat_map do |test|
-  build = Pathname.new 'build'
-  test_basename = Pathname.new(test).basename('')
-
-  [build + 'riscv' + test_basename].map { |path| path.sub_ext('').to_path }
-end
-
 SOURCES = FileList['source/**/*.d']
 
-directory 'build'
+directory 'build/riscv'
 
 CLEAN.include 'build'
 CLEAN.include '.dub'
 
-rule(/build\/riscv\/[^\/\.]+$/ => ->(file) { test_for_out(file, '.o') }) do |t|
-  sh '/opt/riscv/bin/riscv32-unknown-elf-ld',
-    '-o', t.name,
-    '-L/opt/riscv/lib/gcc/riscv32-unknown-elf/13.2.0/',
-    '-L/opt/riscv/riscv32-unknown-elf/lib',
-    '/opt/riscv/riscv32-unknown-elf/lib/crt0.o',
-    '/opt/riscv/lib/gcc/riscv32-unknown-elf/13.2.0/crtbegin.o',
-    t.source,
-    '--start-group', '-lgcc', '-lc', '-lgloss', '--end-group',
-    '/opt/riscv/lib/gcc/riscv32-unknown-elf/13.2.0/crtend.o'
-end
-
-rule(/build\/riscv\/.+\.o$/ => ->(file) { test_for_object(file, '.eln') }) do |t|
-  Pathname.new(t.name).dirname.mkpath
-  sh BINARY, '-o', t.name, t.source
-end
-
 file BINARY => SOURCES do |t|
   sh({ 'DFLAGS' => (DFLAGS * ' ') }, 'dub', 'build', '--compiler=gdc')
 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\/[[:alpha:]]+\//, 'tests/expectations/')
-      .to_path
-
-    puts "Running #{test}"
-    if test.include? '/riscv/'
-      spike = [
-        '/opt/riscv/bin/spike',
-        '--isa=RV32IMAC',
-        '/opt/riscv/riscv32-unknown-elf/bin/pk',
-        test
-      ]
-      diff = ['diff', '-Nur', '--color', expected, '-']
-      tail = ['tail', '-n', '1']
-
-      last_stdout, wait_threads = Open3.pipeline_r spike, tail, diff
-    else
-      raise 'Unsupported test platform'
-    end
-    print last_stdout.read
-    last_stdout.close
-
-    fail unless wait_threads.last.value.exitstatus.zero?
-  end
-end
-
-def test_for_object(out_file, extension)
-  test_source = Pathname
-    .new(out_file)
-    .sub_ext(extension)
-    .sub(/^build\/[[:alpha:]]+\//, 'tests/')
-    .to_path
-  [test_source, BINARY]
-end
-
-def test_for_out(out_file, extension)
-  Pathname
-    .new(out_file)
-    .sub_ext(extension)
-    .to_path
-end

dub.json

@@ -5,5 +5,7 @@
 	"name": "elna",
 	"targetType": "executable",
 	"targetPath": "build/bin",
-	"mainSourceFile": "source/main.d"
+	"mainSourceFile": "source/main.d",
+	"libs": ["elna", "stdc++"],
+	"lflags": ["-Lbuild"]
 }

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

@@ -14,10 +14,10 @@ namespace elna
         class const_iterator
         {
             std::string::const_iterator m_buffer;
-            source_position m_position;
+            Position m_position;
 
             const_iterator(std::string::const_iterator buffer,
-                    const source_position position = source_position());
+                    const Position position = Position());
 
         public:
             using iterator_category = std::forward_iterator_tag;
@@ -26,7 +26,7 @@ namespace elna
             using pointer = const value_type *;
             using reference = const value_type&;
 
-            const source_position& position() const noexcept;
+            const Position& position() const noexcept;
 
             reference operator*() const noexcept;
             pointer operator->() const noexcept;
@@ -43,38 +43,61 @@ namespace elna
         const_iterator end() const;
 
     private:
-        const std::string& m_buffer;
+        const std::string m_buffer;
     };
 
     /**
      * Union type representing a single token.
      */
-    struct token
+    struct Token
     {
         /**
          * Token type.
          */
-        enum class type
+        enum Type : std::uint16_t
         {
-            word,
+            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.
          */
-        using value = std::string;
+        union Value
+        {
+            std::int32_t number;
+            const char *identifier;
+        };
 
-        token(const type of, source::const_iterator begin, source::const_iterator end);
+        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();
 
-        type of() const noexcept;
+        Token& operator=(const Token& that);
-        const value& identifier() const noexcept;
+        Token& operator=(Token&& that);
-        const source_position& position() const noexcept;
+
+        Type of() const noexcept;
+        const char *identifier() const noexcept;
+        std::int32_t number() const noexcept;
+        const Position& position() const noexcept;
 
     private:
-        std::string m_value;
+        Type m_type;
-        source_position m_position;
+        Value m_value;
-        type m_type;
+        Position m_position;
     };
 
     /**
@@ -82,5 +105,5 @@ namespace elna
      *
      * \return Tokens or error.
      */
-    result<std::vector<token>> lex(const std::string& buffer);
+    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

@@ -8,7 +8,7 @@ namespace elna
     /**
      * Position in the source text.
      */
-    struct source_position
+    struct Position
     {
         /// Line.
         std::size_t line = 1;
@@ -20,18 +20,18 @@ namespace elna
     /**
      * A compilation error consists of an error message and position.
      */
-    struct compile_error
+    struct CompileError
     {
     private:
         char const *message;
-        source_position position;
+        Position position;
 
     public:
         /**
          * @param message Error text.
          * @param position Error position in the source text.
          */
-        compile_error(char const *message, const source_position position) noexcept;
+        CompileError(char const *message, const Position position) noexcept;
 
         /// Error text.
         const char *what() const noexcept;
@@ -44,5 +44,19 @@ namespace elna
     };
 
     template<typename T>
-    using result = boost::outcome_v2::result<T, compile_error>;
+    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;
+    };
+}

source/elna/backend.d

@@ -2,6 +2,7 @@ module elna.backend;
 
 import core.stdc.stdio;
 import core.stdc.stdlib;
+import core.stdc.string;
 import elna.elf;
 import elna.ir;
 import elna.extended;
@@ -17,7 +18,7 @@ import tanya.container.array;
 import tanya.container.string;
 import tanya.memory.allocator;
 
-private Nullable!String readSource(string source) @nogc
+private char* readSource(string source) @nogc
 {
     enum size_t bufferSize = 255;
     auto sourceFilename = String(source);
@@ -25,31 +26,39 @@ private Nullable!String readSource(string source) @nogc
     return readFile(sourceFilename).match!(
         (ErrorCode errorCode) {
             perror(sourceFilename.toStringz);
-            return Nullable!String();
+            return null;
         },
-        (Array!ubyte contents) => nullable(String(cast(char[]) contents.get))
+        (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.isNull)
+    if (sourceText is null)
     {
         return 3;
     }
-    auto tokens = lex(sourceText.get.get);
+    CompileError compileError = void;
-    if (!tokens.valid)
+    size_t tokensCount;
+    auto tokens = lex(sourceText, &compileError, &tokensCount);
+    free(sourceText);
+    if (tokens is null)
     {
-        auto compileError = tokens.error.get;
+        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.what);
-        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.message.ptr);
         return 1;
     }
-    auto ast = parse(tokens.result);
+    auto ast = parse(tokens[0 .. tokensCount]);
     if (!ast.valid)
     {
-        auto compileError = ast.error.get;
+        compileError = ast.error.get;
-        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.message.ptr);
+        printf("%lu:%lu: %s\n", compileError.line, compileError.column, compileError.what);
         return 2;
     }
     auto transformVisitor = cast(TransformVisitor) malloc(__traits(classInstanceSize, TransformVisitor));
@@ -85,18 +94,18 @@ int generate(string inFile, ref String outputFilename) @nogc
 
         final switch (reference.target)
         {
-            case Reference.Target.text:
+            case Target.text:
                 relocationEntry.r_info = R_RISCV_CALL;
                 break;
-            case Reference.Target.high20:
+            case Target.high20:
                 relocationEntry.r_info = R_RISCV_HI20;
                 break;
-            case Reference.Target.lower12i:
+            case Target.lower12i:
                 relocationEntry.r_info = R_RISCV_LO12_I;
                 break;
         }
 
-        elf.relocate(reference.name, relocationEntry, relocationSub);
+        elf.relocate(String(reference.name[0 .. strlen(reference.name)]), relocationEntry, relocationSub);
     }
 
     elf.finish();

source/elna/ir.d

@@ -1,5 +1,6 @@
 module elna.ir;
 
+import core.stdc.stdlib;
 import parser = elna.parser;
 import tanya.container.array;
 import tanya.container.hashtable;
@@ -14,7 +15,6 @@ struct ASTMapping
 {
     alias Node = .Node;
     alias Definition = .Definition;
-    alias VariableDeclaration = .VariableDeclaration;
     alias Statement = .Operand;
     alias BangStatement = .Operand;
     alias Block = .Definition;
@@ -28,20 +28,21 @@ struct ASTMapping
 /**
  * IR visitor.
 */
-interface IRVisitor
+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(VariableDeclaration) @nogc;
     abstract void visit(Number) @nogc;
 }
 
 /**
  * AST node.
  */
+extern(C++, "elna", "ir")
 abstract class Node
 {
     abstract void accept(IRVisitor) @nogc;
@@ -50,99 +51,69 @@ abstract class Node
 /**
  * Definition.
  */
+extern(C++, "elna", "ir")
 class Definition : Node
 {
-    char[] identifier;
+    BinaryExpression* statements;
-    Array!BinaryExpression statements;
+    size_t statementsLength;
-    Array!VariableDeclaration variableDeclarations;
     Operand result;
 
-    override void accept(IRVisitor visitor) @nogc
+    override void accept(IRVisitor visitor) @nogc;
-    {
-        visitor.visit(this);
-    }
 }
 
+extern(C++, "elna", "ir")
 abstract class Statement : Node
 {
 }
 
+extern(C++, "elna", "ir")
 abstract class Operand : Node
 {
-    override void accept(IRVisitor visitor) @nogc
+    override void accept(IRVisitor visitor) @nogc;
-    {
-        visitor.visit(this);
-    }
 }
 
+extern(C++, "elna", "ir")
 class Number : Operand
 {
     int value;
 
-    override void accept(IRVisitor visitor) @nogc
+    override void accept(IRVisitor visitor) @nogc;
-    {
-        visitor.visit(this);
-    }
 }
 
+extern(C++, "elna", "ir")
 class Variable : Operand
 {
     size_t counter;
 
-    override void accept(IRVisitor visitor) @nogc
+    override void accept(IRVisitor visitor) @nogc;
-    {
-        visitor.visit(this);
-    }
-}
-
-class VariableDeclaration : Node
-{
-    String identifier;
-
-    override void accept(IRVisitor visitor) @nogc
-    {
-        visitor.visit(this);
-    }
 }
 
+extern(C++, "elna", "ir")
 class BinaryExpression : Statement
 {
     Operand lhs, rhs;
     BinaryOperator operator;
 
-    this(Operand lhs, Operand rhs, BinaryOperator operator)
+    this(Operand lhs, Operand rhs, BinaryOperator operator) @nogc;
-    @nogc
-    {
-        this.lhs = lhs;
-        this.rhs = rhs;
-        this.operator = operator;
-    }
 
-    override void accept(IRVisitor visitor) @nogc
+    override void accept(IRVisitor visitor) @nogc;
-    {
-        visitor.visit(this);
-    }
 }
 
+extern(C++, "elna", "ir")
 class BangExpression : Statement
 {
     Operand operand;
 
-    this(Operand operand)
+    this(Operand operand);
-    {
-        this.operand = operand;
-    }
 
-    override void accept(IRVisitor visitor) @nogc
+    override void accept(IRVisitor visitor) @nogc;
-    {
-        visitor.visit(this);
-    }
 }
 
 final class TransformVisitor : parser.ParserVisitor!ASTMapping
 {
     private HashTable!(String, int) constants;
-    private Array!BinaryExpression statements;
+    private BinaryExpression* statements;
+    private size_t statementsLength;
 
     ASTMapping.Node visit(parser.Node node) @nogc
     {
@@ -154,11 +125,6 @@ final class TransformVisitor : parser.ParserVisitor!ASTMapping
         assert(false, "Not implemented");
     }
 
-    ASTMapping.VariableDeclaration visit(parser.VariableDeclaration declaration) @nogc
-    {
-        assert(false, "Not implemented");
-    }
-
     ASTMapping.BangStatement visit(parser.BangStatement statement) @nogc
     {
         return statement.expression.accept(this);
@@ -171,8 +137,7 @@ final class TransformVisitor : parser.ParserVisitor!ASTMapping
 
         target.result = block.statement.accept(this);
         target.statements = this.statements;
-
+        target.statementsLength = this.statementsLength;
-        target.variableDeclarations = transformVariableDeclarations(block.variableDeclarations);
 
         return target;
     }
@@ -217,10 +182,12 @@ final class TransformVisitor : parser.ParserVisitor!ASTMapping
             binaryExpression.rhs.accept(this),
             binaryExpression.operator
         );
-        statements.insertBack(target);
+        this.statements = cast(BinaryExpression*)
+            realloc(this.statements, (this.statementsLength + 1) * BinaryExpression.sizeof);
+        this.statements[this.statementsLength++] = target;
 
         auto newVariable = defaultAllocator.make!Variable;
-        newVariable.counter = statements.length;
+        newVariable.counter = this.statementsLength;
 
         return newVariable;
     }
@@ -250,19 +217,4 @@ final class TransformVisitor : parser.ParserVisitor!ASTMapping
 
         return constants;
     }
-
-    Array!VariableDeclaration transformVariableDeclarations(ref Array!(parser.VariableDeclaration) variableDeclarations)
-    @nogc
-    {
-        typeof(return) variables;
-
-        foreach (ref variableDeclaration; variableDeclarations)
-        {
-            auto newDeclaration = defaultAllocator.make!VariableDeclaration;
-            newDeclaration.identifier = variableDeclaration.identifier;
-            variables.insertBack(newDeclaration);
-        }
-
-        return variables;
-    }
 }

source/elna/lexer.d

@@ -8,28 +8,29 @@ import std.range;
 import tanya.container.array;
 import tanya.container.string;
 
+extern(C++, "elna")
 struct Token
 {
-    enum Type
+    enum Type : ushort
     {
-        number,
+        number = 0,
-        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;
@@ -38,62 +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 || type == Type.operator)
-    {
-        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 || type == Type.operator)
-        {
-            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_;
-    }
 }
 
 /**
@@ -101,10 +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;
     }
@@ -113,7 +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
@@ -122,133 +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];
     }
 }
 
-Result!(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 == '+' || source.front == '-')
-        {
-            String operator;
-
-            operator.insertBack(source.front);
-            tokens.insertBack(Token(Token.Type.operator, operator, source.position));
-            source.popFront;
-        }
-        else if (source.front == '\n')
-        {
-            source.breakLine;
-        }
-        else
-        {
-            return typeof(return)("Unexptected next character", source.position);
-        }
-    }
-    return typeof(return)(tokens);
-}

source/elna/parser.d

@@ -1,11 +1,12 @@
 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 std.array;
 
 /**
  * Parser visitor.
@@ -14,7 +15,6 @@ interface ParserVisitor(Mapping)
 {
     Mapping.Node visit(Node) @nogc;
     Mapping.Definition visit(Definition) @nogc;
-    Mapping.VariableDeclaration visit(VariableDeclaration) @nogc;
     Mapping.Statement visit(Statement) @nogc;
     Mapping.BangStatement visit(BangStatement) @nogc;
     Mapping.Block visit(Block) @nogc;
@@ -49,19 +49,6 @@ class Definition : Node
     }
 }
 
-/**
- * Variable declaration.
- */
-class VariableDeclaration : Node
-{
-    String identifier;
-
-    Mapping.VariableDeclaration accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
-    {
-        return visitor.visit(this);
-    }
-}
-
 abstract class Statement : Node
 {
     Mapping.Statement accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
@@ -83,7 +70,6 @@ class BangStatement : Statement
 class Block : Node
 {
     Array!Definition definitions;
-    Array!VariableDeclaration variableDeclarations;
     Statement statement;
 
     Mapping.Block accept(Mapping)(ParserVisitor!Mapping visitor) @nogc
@@ -120,6 +106,7 @@ class Variable : Expression
     }
 }
 
+extern(C++, "elna")
 enum BinaryOperator
 {
     sum,
@@ -155,24 +142,24 @@ class BinaryExpression : Expression
     }
 }
 
-private Result!Expression parseFactor(ref Array!Token.Range tokens) @nogc
+private Result!Expression parseFactor(ref Token[] tokens) @nogc
 in (!tokens.empty, "Expected factor, got end of stream")
 {
-    if (tokens.front.ofType(Token.Type.identifier))
+    if (tokens.front.of() == Token.Type.identifier)
     {
         auto variable = defaultAllocator.make!Variable;
-        variable.identifier = tokens.front.value!(Token.Type.identifier);
+        variable.identifier = tokens.front.identifier()[0 .. strlen(tokens.front.identifier())];
         tokens.popFront;
         return Result!Expression(variable);
     }
-    else if (tokens.front.ofType(Token.Type.number))
+    else if (tokens.front.of() == Token.Type.number)
     {
         auto number = defaultAllocator.make!Number;
-        number.value = tokens.front.value!(Token.Type.number);
+        number.value = tokens.front.number();
         tokens.popFront;
         return Result!Expression(number);
     }
-    else if (tokens.front.ofType(Token.Type.leftParen))
+    else if (tokens.front.of() == Token.Type.leftParen)
     {
         tokens.popFront;
 
@@ -184,20 +171,20 @@ in (!tokens.empty, "Expected factor, got end of stream")
     return Result!Expression("Expected a factor", tokens.front.position);
 }
 
-private Result!Expression parseTerm(ref Array!(Token).Range tokens) @nogc
+private Result!Expression parseTerm(ref Token[] tokens) @nogc
 {
     return parseFactor(tokens);
 }
 
-private Result!Expression parseExpression(ref Array!(Token).Range tokens) @nogc
+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.ofType(Token.Type.operator))
+    if (!term.valid || tokens.empty || tokens.front.of() != Token.Type.operator)
     {
         return term;
     }
-    auto operator = tokens.front.value!(Token.Type.operator);
+    auto operator = String(tokens.front.identifier()[0 .. strlen(tokens.front.identifier())]);
     tokens.popFront;
 
     auto expression = parseExpression(tokens);
@@ -215,19 +202,19 @@ in (!tokens.empty, "Expected expression, got end of stream")
     }
 }
 
-private Result!Definition parseDefinition(ref Array!Token.Range tokens) @nogc
+private Result!Definition parseDefinition(ref Token[] tokens) @nogc
 in (!tokens.empty, "Expected definition, got end of stream")
 {
     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 = 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);
@@ -235,10 +222,10 @@ 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 = defaultAllocator.make!BangStatement;
@@ -256,7 +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.
@@ -271,11 +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;
         }
@@ -284,49 +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 = defaultAllocator.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 = defaultAllocator.make!Block;
-    if (tokens.front.ofType(Token.Type.let))
+    if (tokens.front.of() == Token.Type.let)
     {
         auto constDefinitions = parseDefinitions(tokens);
         if (constDefinitions.valid)
@@ -339,19 +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)
     {
@@ -365,7 +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

@@ -7,6 +7,7 @@ import tanya.container.string;
 /**
  * Position in the source text.
  */
+extern(C++, "elna")
 struct Position
 {
     /// Line.
@@ -16,9 +17,10 @@ struct Position
     size_t column = 1;
 }
 
+extern(C++, "elna")
 struct CompileError
 {
-    private string message_;
+    private const(char)* message_;
 
     private Position position_;
 
@@ -29,29 +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)
@@ -65,7 +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);
@@ -85,16 +74,18 @@ struct Result(T)
     }
 }
 
-struct Reference
+extern(C++, "elna")
+enum Target
 {
-    enum Target
-    {
     text,
     high20,
     lower12i
-    }
+}
 
-    String name;
+extern(C++, "elna")
+struct Reference
+{
+    const(char)* name;
     size_t offset;
     Target target;
 }

source/elna/riscv.d

@@ -1,14 +1,12 @@
 module elna.riscv;
 
 import core.stdc.stdlib;
-import elna.extended;
 import elna.ir;
 import elna.result;
-import std.algorithm;
-import std.typecons;
 import tanya.container.array;
 import tanya.container.string;
 
+extern(C++, "elna")
 enum XRegister : ubyte
 {
     zero = 0,
@@ -45,6 +43,7 @@ enum XRegister : ubyte
     t6 = 31,
 }
 
+extern(C++, "elna")
 enum Funct3 : ubyte
 {
     addi = 0b000,
@@ -92,18 +91,21 @@ enum Funct3 : ubyte
     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,
@@ -119,243 +121,61 @@ enum BaseOpcode : ubyte
     system = 0b1110011,
 }
 
+extern(C++, "elna")
 struct Instruction
 {
     private uint instruction;
 
-    this(BaseOpcode opcode) @nogc
+    this(BaseOpcode opcode) @nogc;
-    {
-        this.instruction = opcode;
-    }
     @disable this();
 
     ref Instruction i(XRegister rd, Funct3 funct3, XRegister rs1, uint immediate)
-    return scope @nogc
+    return scope @nogc;
-    {
-        this.instruction |= (rd << 7)
-            | (funct3 << 12)
-            | (rs1 << 15)
-            | (immediate << 20);
-
-        return this;
-    }
 
     ref Instruction s(uint imm1, Funct3 funct3, XRegister rs1, XRegister rs2)
-    return scope @nogc
+    return scope @nogc;
-    {
-        this.instruction |= ((imm1 & 0b11111) << 7)
-            | (funct3 << 12)
-            | (rs1 << 15)
-            | (rs2 << 20)
-            | ((imm1 & 0b111111100000) << 20);
-
-        return this;
-    }
 
     ref Instruction r(XRegister rd, Funct3 funct3, XRegister rs1, XRegister rs2, Funct7 funct7 = Funct7.none)
-    return scope @nogc
+    return scope @nogc;
-    {
-        this.instruction |= (rd << 7)
-            | (funct3 << 12)
-            | (rs1 << 15)
-            | (rs2 << 20)
-            | (funct7 << 25);
-
-        return this;
-    }
 
     ref Instruction u(XRegister rd, uint imm)
-    return scope @nogc
+    return scope @nogc;
-    {
-        this.instruction |= (rd << 7) | (imm << 12);
 
-        return this;
+    ubyte* encode() return scope @nogc;
-    }
-
-    ubyte* encode() return scope @nogc
-    {
-        return cast(ubyte*) (&this.instruction);
-    }
 }
 
+extern(C++, "elna")
 class RiscVVisitor : IRVisitor
 {
-    Array!Instruction instructions;
+    Instruction *instructions;
+    size_t instructionsLength;
     bool registerInUse;
     uint variableCounter = 1;
-    Array!Reference references;
+    Reference[3] references;
 
-    override void visit(Node) @nogc
+    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(Definition definition) @nogc
+    override void visit(Number number) @nogc;
-    {
+    override void visit(BinaryExpression expression) @nogc;
-        const uint stackSize = cast(uint) (definition.statements.length * 4 + 12);
-
-        // Prologue.
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.opImm)
-                .i(XRegister.sp, Funct3.addi, XRegister.sp, -stackSize)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.store)
-                .s(stackSize - 4, Funct3.sw, XRegister.sp, XRegister.s0)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.store)
-                .s(stackSize - 8, Funct3.sw, XRegister.sp, XRegister.ra)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.opImm)
-                .i(XRegister.s0, Funct3.addi, XRegister.sp, stackSize)
-        );
-
-        foreach (statement; definition.statements[])
-        {
-            statement.accept(this);
-        }
-        foreach (variableDeclaration; definition.variableDeclarations[])
-        {
-            variableDeclaration.accept(this);
-        }
-        this.registerInUse = true;
-        definition.result.accept(this);
-        this.registerInUse = false;
-
-        // Print the result.
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.opImm)
-                .i(XRegister.a1, Funct3.addi, XRegister.a0, 0)
-        );
-        this.references.insertBack(Reference(String(".CL0"), instructions.length * 4, Reference.Target.high20));
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.lui).u(XRegister.a5, 0)
-        );
-        this.references.insertBack(Reference(String(".CL0"), instructions.length * 4, Reference.Target.lower12i));
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.opImm).i(XRegister.a0, Funct3.addi, XRegister.a5, 0)
-        );
-        this.references.insertBack(Reference(String("printf"), instructions.length * 4, Reference.Target.text));
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.auipc).u(XRegister.ra, 0)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.jalr)
-                .i(XRegister.ra, Funct3.jalr, XRegister.ra, 0)
-        );
-        // Set the return value (0).
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.op)
-                .r(XRegister.a0, Funct3.and, XRegister.zero, XRegister.zero)
-        );
-
-        // Epilogue.
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.load)
-                .i(XRegister.s0, Funct3.lw, XRegister.sp, stackSize - 4)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.load)
-                .i(XRegister.ra, Funct3.lw, XRegister.sp, stackSize - 8)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.opImm)
-                .i(XRegister.sp, Funct3.addi, XRegister.sp, stackSize)
-        );
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.jalr)
-                .i(XRegister.zero, Funct3.jalr, XRegister.ra, 0)
-        );
-    }
-
-    override void visit(Operand operand) @nogc
-    {
-        if ((cast(Variable) operand) !is null)
-        {
-            return (cast(Variable) operand).accept(this);
-        }
-        if ((cast(Number) operand) !is null)
-        {
-            return (cast(Number) operand).accept(this);
-        }
-    }
-
-    override void visit(Variable variable) @nogc
-    {
-        const freeRegister = this.registerInUse ? XRegister.a0 : XRegister.t0;
-
-        // movl -x(%rbp), %eax; where x is a number.
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.load)
-                .i(freeRegister, Funct3.lw, XRegister.sp,
-                    cast(byte) (variable.counter * 4))
-        );
-    }
-
-    override void visit(VariableDeclaration) @nogc
-    {
-    }
-
-    override void visit(Number number) @nogc
-    {
-        const freeRegister = this.registerInUse ? XRegister.a0 : XRegister.t0;
-
-        this.instructions.insertBack(
-            Instruction(BaseOpcode.opImm) // movl $x, %eax; where $x is a number.
-                .i(freeRegister, Funct3.addi, XRegister.zero, number.value)
-        );
-    }
-
-    override void visit(BinaryExpression expression) @nogc
-    {
-        this.registerInUse = true;
-        expression.lhs.accept(this);
-        this.registerInUse = false;
-        expression.rhs.accept(this);
-
-        // Calculate the result and assign it to a variable on the stack.
-        final switch (expression.operator)
-        {
-            case BinaryOperator.sum:
-                this.instructions.insertBack(
-                    Instruction(BaseOpcode.op)
-                        .r(XRegister.a0, Funct3.add, XRegister.a0, XRegister.t0)
-                );
-                break;
-            case BinaryOperator.subtraction:
-                this.instructions.insertBack(
-                    Instruction(BaseOpcode.op)
-                        .r(XRegister.a0, Funct3.sub, XRegister.a0, XRegister.t0, Funct7.sub)
-                );
-                break;
-        }
-        this.instructions.insertBack( // movl %eax, -x(%rbp); where x is a number.
-            Instruction(BaseOpcode.store)
-                .s(cast(uint) (this.variableCounter * 4), Funct3.sw, XRegister.sp, XRegister.a0)
-        );
-
-        ++this.variableCounter;
-    }
 }
 
 Symbol writeNext(Definition ast) @nogc
 {
     Array!Instruction instructions;
-    Array!Reference references;
     auto visitor = cast(RiscVVisitor) malloc(__traits(classInstanceSize, RiscVVisitor));
     (cast(void*) visitor)[0 .. __traits(classInstanceSize, RiscVVisitor)] = __traits(initSymbol, RiscVVisitor)[];
     scope (exit)
     {
-        visitor.__xdtor();
         free(cast(void*) visitor);
     }
     visitor.visit(ast);
 
     auto program = Symbol(String("main"));
 
-    program.symbols = move(visitor.references);
+    program.symbols = Array!Reference(visitor.references[]);
-    foreach (ref instruction; visitor.instructions)
+    foreach (ref instruction; visitor.instructions[0 .. visitor.instructionsLength])
     {
         program.text.insertBack(instruction.encode[0 .. uint.sizeof]);
     }

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

@@ -14,18 +14,18 @@ namespace elna
 
     source::const_iterator source::end() const
     {
-        source_position end_position{ 0, 0 };
+        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 source_position start_position)
+            const Position start_position)
         : m_buffer(buffer), m_position(start_position)
     {
     }
 
-    const source_position& source::const_iterator::position() const noexcept
+    const Position& source::const_iterator::position() const noexcept
     {
         return this->m_position;
     }
@@ -73,29 +73,109 @@ namespace elna
         return !(*this == that);
     }
 
-    token::token(const type of, source::const_iterator begin, source::const_iterator end)
+    Token::Token(const Type of, const char *value, Position position)
-        : m_type(of), m_value(begin, end)
+        : 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::type token::of() const noexcept
+    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 token::value& token::identifier() const noexcept
+    const char *Token::identifier() const noexcept
     {
-        return m_value;
+        return m_value.identifier;
     }
 
-    const source_position& token::position() const noexcept
+    std::int32_t Token::number() const noexcept
+    {
+        return m_value.number;
+    }
+
+    const Position& Token::position() const noexcept
     {
         return m_position;
     }
 
-    result<std::vector<token>> lex(const std::string& buffer)
+    Token *lex(const char *buffer, CompileError *compile_error, std::size_t *length)
     {
-        std::vector<token> tokens;
+        std::vector<Token> tokens;
         source input{ buffer };
 
         for (auto iterator = input.begin(); iterator != input.end();)
@@ -103,23 +183,88 @@ namespace elna
             if (*iterator == ' ' || *iterator == '\n')
             {
             }
-            else if (std::isgraph(*iterator))
+            else if (std::isdigit(*iterator))
             {
-                auto current_position = iterator;
+                tokens.emplace_back(
-                do
+                        Token::TOKEN_NUMBER,
-                {
+                        static_cast<std::int32_t>(*iterator - '0'),
-                    ++current_position;
+                        iterator.position()
+                );
             }
-                while (current_position != input.end() && std::isgraph(*current_position));
+            else if (*iterator == '=')
-                token new_token{ token::type::word, iterator, current_position };
+            {
-
+                tokens.emplace_back(Token::TOKEN_EQUALS, iterator.position());
-                tokens.push_back(new_token);
+            }
-                iterator = current_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 tokens;
+        return target;
     }
 }

source/result.cpp

@@ -2,23 +2,23 @@
 
 namespace elna
 {
-    compile_error::compile_error(const char *message, const source_position position) noexcept
+    CompileError::CompileError(const char *message, const Position position) noexcept
     {
         this->message = message;
         this->position = position;
     }
 
-    char const *compile_error::what() const noexcept
+    char const *CompileError::what() const noexcept
     {
         return this->message;
     }
 
-    std::size_t compile_error::line() const noexcept
+    std::size_t CompileError::line() const noexcept
     {
         return this->position.line;
     }
 
-    std::size_t compile_error::column() const noexcept
+    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;
+    }
+}