fix: fix this mess

I am stupid
I am stupid
I am stupid
I can't believe how f- ricking stupid I am

.clang-tidy

@@ -31,7 +31,9 @@ Checks: >
   -cppcoreguidelines-non-private-member-variables-in-classes,
   -cppcoreguidelines-pro-bounds-avoid-unchecked-container-access,
   -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
-  -bugprone-forward-declaration-namespace
+  -cppcoreguidelines-use-enum-class,
+  -bugprone-forward-declaration-namespace,
+  -bugprone-tagged-union-member-count
 
 WarningsAsErrors: "*"
 

CMakeLists.txt

@@ -14,6 +14,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 add_subdirectory(furlang)
 add_subdirectory(furvm)
 add_subdirectory(furc)
+add_subdirectory(furas)
 
 if(DOXYGEN_FOUND)
     set(DOXYGEN_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/docs)

furas/CMakeLists.txt

@@ -0,0 +1,5 @@
+file(GLOB_RECURSE FURAS_SRCS "src/**.cpp")
+file(GLOB_RECURSE FURAS_HDRS "include/**.hpp")
+add_executable(furas ${FURAS_SRCS} ${FURAS_HDRS})
+target_include_directories(furas PUBLIC include/)
+target_link_libraries(furas PRIVATE furlang libfurvm)

furas/examples/array.furas

@@ -0,0 +1,35 @@
+type arr = array $s8 10
+
+func println $arr = native println
+
+public func main = #main
+main:
+    array $arr
+    dup
+    store %0
+
+    lenof
+    store %1
+
+    push $s32 0
+loop:
+    dup
+    load %1
+    ge
+    jnz #end
+body:
+    dup
+    load %0
+    swap
+    push $s8 69
+    set
+
+    push $s32 1
+    add
+
+    jmp #loop
+end:
+    drop
+    load %0
+    call $arr println
+    ret

furas/examples/array2.furas

@@ -0,0 +1,34 @@
+type arr = array $s8 10
+
+func println $arr = native println
+
+public func main = #main
+main:
+    array $arr
+    store %0
+
+    push $s32 2
+    store %1
+
+    push $s32 0
+loop:
+    dup
+    load %1
+    ge
+    jnz #end
+body:
+    dup
+    load %0
+    swap
+    push $s8 69
+    set
+
+    push $s32 1
+    add
+
+    jmp #loop
+end:
+    drop
+    load %0
+    call $arr println
+    ret

furas/examples/ops.furas

@@ -0,0 +1,23 @@
+func println $u32 = native println
+
+public func main = #main
+main:
+    push $u32 0
+    store %0
+loop_header:
+    load %0
+    push $u32 10
+    ge
+    jnz #loop_end
+loop_body:
+    load %0
+    call $u32 println
+
+    load %0
+    push $u32 1
+    add
+    store %0
+
+    jmp #loop_header
+loop_end:
+    ret

furas/include/furas/gen.hpp

@@ -0,0 +1,36 @@
+#ifndef FURAS_GEN_HPP
+#define FURAS_GEN_HPP
+
+#include "furas/lexer.hpp"
+#include "furvm/module.hpp"
+
+#include <string>
+
+namespace furas {
+
+struct generator_error {
+    enum type {
+        Success = 0,
+        Eof     = 1,
+
+        UnexpectedEof    = -1,
+        UnexpectedToken  = -2,
+        UnknownCharacter = -3,
+        UnknownType      = -4,
+    } type = Success;
+    std::string message;
+};
+
+class generator {
+public:
+    struct result {
+        generator_error error;
+        furvm::mod      mod;
+    };
+public:
+    static result generate(lexer lexer);
+};
+
+} // namespace furas
+
+#endif // FURAS_GEN_HPP

furas/include/furas/lexer.hpp

@@ -0,0 +1,47 @@
+#ifndef FURAS_LEXER_HPP
+#define FURAS_LEXER_HPP
+
+#include "furas/token.hpp"
+#include "furlang/result.hpp"
+
+#include <cstddef>
+#include <string_view>
+
+namespace furas {
+
+struct lexer_location {
+    std::string_view filename;
+    std::size_t      row, col;
+};
+
+struct lexer_error {
+    enum type {
+        EndOfFile = 0,
+        UnknownCharacter,
+    } type;
+
+    lexer_location location;
+    std::string    message;
+};
+
+using token_r = furlang::result<token, lexer_error>;
+
+class lexer {
+public:
+    lexer(std::string_view filename, std::string_view content)
+      : m_filename(filename), m_content(content) {}
+
+    token_r next_token();
+private:
+    constexpr lexer_location location() const { return { m_filename, m_cursor - m_lineStart, m_column }; }
+private:
+    std::string_view m_filename;
+    std::string_view m_content;
+    std::size_t      m_cursor    = 0;
+    std::size_t      m_lineStart = 0;
+    std::size_t      m_column    = 0;
+};
+
+} // namespace furas
+
+#endif // FURAS_LEXER_HPP

furas/include/furas/token.hpp

@@ -0,0 +1,94 @@
+#ifndef FURAS_TOKEN_HPP
+#define FURAS_TOKEN_HPP
+
+#include <cstdint>
+#include <string_view>
+
+namespace furas {
+
+struct token {
+    enum type {
+        Identifier = 0, /**< An identifier. */
+        Signed,         /**< A signed integer. */
+        Unsigned,       /**< An unsigned integer. */
+
+        // Markers
+        Monkey,  /**< Constant marker (`@`). */
+        Dolar,   /**< Type marker(`$`). */
+        Sha256,  /**< Label marker(`#`). */
+        Percent, /**< Variable marker(`%`). The more the better. */
+
+        EqSign, /**< `=` */
+        Dot,    /**< . */
+        Colon,  /**< `:` */
+
+        // Keywords
+        Func,    /**< `func` keyword for defining functions. */
+        Type,    /**< `type` keyword for defining types. */
+        Native,  /**< `native` keyword for native functions. :v: */
+        Import,  /**< `import` keyword for importing functions and types. */
+        Public,  /**< `public` access specifier. */
+        Private, /**< `private` access specifier. */
+
+        // Instructions
+        Push,
+        Array,
+        Get,
+        Set,
+        Drop,
+        Dup,
+        Swap,
+        Clone,
+        Ref,
+        Add,
+        Sub,
+        Mul,
+        Div,
+        Mod,
+        Eq,
+        Neq,
+        Lt,
+        Gt,
+        Le,
+        Ge,
+        Ptrof,
+        Sizeof,
+        Lenof,
+        Load,
+        Store,
+        Call,
+        Jmp,
+        Jnz,
+        Ret,
+
+        Count
+    } type = Count;
+    union value {
+        std::nullptr_t   null = nullptr;
+        std::string_view string;
+        std::int64_t     integer;
+        std::uint64_t    uint;
+    } value;
+
+    token(enum type type)
+      : type(type) {}
+
+    token(enum type type, std::string_view string)
+      : type(type) {
+        value.string = string;
+    }
+
+    token(std::uint64_t num)
+      : type(Unsigned) {
+        value.uint = num;
+    }
+
+    token(std::int64_t num)
+      : type(Signed) {
+        value.integer = num;
+    }
+};
+
+} // namespace furas
+
+#endif // FURAS_TOKEN_HPP

furas/src/gen.cpp

@@ -0,0 +1,558 @@
+#include "furas/gen.hpp"
+
+#include "furas/token.hpp"
+#include "furvm/function.hpp"
+#include "furvm/fwd.hpp"
+#include "furvm/instruction.hpp"
+
+#include <cassert>
+#include <cstdint>
+#include <cstdlib>
+#include <limits>
+#include <optional>
+#include <stdexcept>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+namespace furas {
+
+using namespace std::string_literals;
+
+namespace {
+
+struct instruction {
+    furvm::instruction_t fur{};
+    enum arg_type {
+        None = 0,
+        Type,
+        Constant,
+        Variable,
+        Function,
+        Label,
+    } arg = None;
+};
+
+// NOLINTBEGIN
+std::unordered_map<enum token::type, instruction> instructions = {
+    { token::Array, { furvm::instruction_t::Array, instruction::Type } },
+    { token::Get, { furvm::instruction_t::Get } },
+    { token::Set, { furvm::instruction_t::Set } },
+    { token::Drop, { furvm::instruction_t::Drop } },
+    { token::Dup, { furvm::instruction_t::Duplicate } },
+    { token::Swap, { furvm::instruction_t::Swap } },
+    { token::Clone, { furvm::instruction_t::Clone } },
+    { token::Ref, { furvm::instruction_t::Reference } },
+    { token::Add, { furvm::instruction_t::Add } },
+    { token::Sub, { furvm::instruction_t::Sub } },
+    { token::Mul, { furvm::instruction_t::Mul } },
+    { token::Div, { furvm::instruction_t::Div } },
+    { token::Mod, { furvm::instruction_t::Mod } },
+    { token::Eq, { furvm::instruction_t::Equals } },
+    { token::Neq, { furvm::instruction_t::NotEquals } },
+    { token::Lt, { furvm::instruction_t::LessThan } },
+    { token::Gt, { furvm::instruction_t::GreaterThan } },
+    { token::Le, { furvm::instruction_t::LessEqual } },
+    { token::Ge, { furvm::instruction_t::GreaterEqual } },
+    { token::Ptrof, { furvm::instruction_t::Pointerof } },
+    { token::Sizeof, { furvm::instruction_t::Sizeof } },
+    { token::Lenof, { furvm::instruction_t::Lengthof } },
+    { token::Load, { furvm::instruction_t::Load, instruction::Variable } },
+    { token::Store, { furvm::instruction_t::Store, instruction::Variable } },
+    { token::Call, { furvm::instruction_t::Call, instruction::Function } },
+    { token::Jmp, { furvm::instruction_t::Jump, instruction::Label } },
+    { token::Jnz, { furvm::instruction_t::JumpNotZero, instruction::Label } },
+    { token::Ret, { furvm::instruction_t::Return } },
+};
+// NOLINTEND
+
+const char* token_type(enum token::type type) {
+    switch (type) {
+    case token::Identifier: return "identifier";
+    case token::Signed: return "signed";
+    case token::Unsigned: return "unsigned";
+    case token::Monkey: return "'@'";
+    case token::Dolar: return "'$'";
+    case token::Sha256: return "'#'";
+    case token::Percent: return "'%'";
+    case token::EqSign: return "'='";
+    case token::Dot: return "'.'";
+    case token::Colon: return "':'";
+    case token::Func: return "func";
+    case token::Type: return "type";
+    case token::Native: return "native";
+    case token::Import: return "import";
+    case token::Public: return "public";
+    case token::Private: return "private";
+    case token::Push: return "push";
+    case token::Array: return "array";
+    case token::Get: return "get";
+    case token::Set: return "set";
+    case token::Drop: return "drop";
+    case token::Dup: return "dup";
+    case token::Swap: return "swap";
+    case token::Clone: return "clone";
+    case token::Ref: return "ref";
+    case token::Add: return "add";
+    case token::Sub: return "sub";
+    case token::Mul: return "mul";
+    case token::Div: return "div";
+    case token::Mod: return "mod";
+    case token::Eq: return "eq";
+    case token::Neq: return "neq";
+    case token::Lt: return "lt";
+    case token::Gt: return "gt";
+    case token::Le: return "le";
+    case token::Ge: return "ge";
+    case token::Ptrof: return "ptrof";
+    case token::Sizeof: return "sizeof";
+    case token::Lenof: return "lenof";
+    case token::Load: return "load";
+    case token::Store: return "store";
+    case token::Call: return "call";
+    case token::Jmp: return "jmp";
+    case token::Jnz: return "jnz";
+    case token::Ret: return "ret";
+    case token::Count: break;
+    }
+    throw std::runtime_error("unreachable");
+}
+
+struct mod_context {
+    struct label_context {
+        struct function_info {
+            std::string         name;
+            furvm::function_sig signature;
+            bool                pub;
+        };
+
+        static constexpr std::size_t INVALID = std::numeric_limits<std::size_t>::max();
+
+        std::size_t                offset = INVALID;
+        std::vector<function_info> functions;
+        std::vector<std::size_t>   unknowns;
+    };
+
+    furvm::mod mod;
+    std::unordered_map<std::pair<std::string, furvm::function_sig>,
+        furvm::function_h,
+        furlang::utility::
+            pair_hash<std::string, furvm::function_sig, std::hash<std::string>, furvm::detail::function_sig_hash>>
+                                                       functions;
+    std::unordered_map<std::string, furvm::mod_type_h> types;
+
+    std::unordered_map<std::string, label_context> labels;
+
+    struct token_result {
+        generator_error error;
+        token           token;
+
+        struct token* operator->() { return &token; }
+        struct token& operator*() { return token; }
+
+        bool operator!() const { return error.type != generator_error::Success; }
+    };
+
+    mod_context() {
+        types.emplace("s8", mod.emplace_type(furvm::mod_type::S8));
+        types.emplace("u8", mod.emplace_type(furvm::mod_type::U8));
+        types.emplace("s16", mod.emplace_type(furvm::mod_type::S16));
+        types.emplace("u16", mod.emplace_type(furvm::mod_type::U16));
+        types.emplace("s32", mod.emplace_type(furvm::mod_type::S32));
+        types.emplace("u32", mod.emplace_type(furvm::mod_type::U32));
+        types.emplace("s64", mod.emplace_type(furvm::mod_type::S64));
+        types.emplace("u64", mod.emplace_type(furvm::mod_type::U64));
+    }
+
+    static token_result next_token(lexer& lexer) {
+        auto token = lexer.next_token();
+        if (token.has_error()) {
+            switch (token.error().type) {
+            case lexer_error::EndOfFile:
+                return { { generator_error::UnexpectedEof, "Unexpected end of file" }, { token::Count } };
+            case lexer_error::UnknownCharacter:
+                return { { generator_error::UnknownCharacter, token.error().message }, { token::Count } };
+            }
+        }
+        return { { generator_error::Success }, *token };
+    }
+
+    static token_result eat_token(lexer& lexer, enum token::type type) {
+        auto token = next_token(lexer);
+        if (!token) return token;
+        if (token.token.type != type) {
+            return { { generator_error::UnexpectedToken,
+                         "Expected "s + token_type(type) + ", but got " + token_type(token->type) },
+                { token::Count } };
+        }
+        return { { generator_error::Success }, token.token };
+    }
+
+    generator_error generate(lexer& lexer) {
+        auto result = next_token(lexer);
+        if (result.error.type == generator_error::UnexpectedEof) return { generator_error::Eof };
+        if (!result) return result.error;
+        switch (result->type) {
+        case token::Identifier: {
+            std::string labelName = std::string(result->value.string);
+
+            result = eat_token(lexer, token::Colon);
+            if (!result) return result.error;
+
+            auto& label = labels[labelName];
+            if (label.offset != label_context::INVALID)
+                return { generator_error::UnexpectedToken, "Label "s + labelName + " already exists" };
+            label.offset = mod.bytecode().size();
+
+            for (auto& func : label.functions) {
+                furvm::function_h handle =
+                    (func.pub ? mod.emplace_function(func.name, std::move(func.signature), label.offset)
+                              : mod.emplace_function(std::move(func.signature), label.offset));
+
+                functions.emplace(std::make_pair(std::move(func.name), std::move(func.signature)), handle);
+
+                handle.dispatch();
+            }
+            for (auto unknown : label.unknowns) {
+                std::ptrdiff_t jmpOff = static_cast<std::ptrdiff_t>(label.offset - unknown);
+                if (jmpOff < std::numeric_limits<std::int8_t>::min() ||
+                    jmpOff > std::numeric_limits<std::int8_t>::max()) {
+                    assert(false); // TODO: Further jumps are not implemented
+                }
+                mod.bytecode()[unknown - 1] = jmpOff;
+            }
+            label.functions = {};
+            label.unknowns  = {};
+            return { generator_error::Success };
+        }
+
+        case token::Func:
+        case token::Type:
+        case token::Public:
+        case token::Private: {
+            bool pub = false;
+            if (result->type == token::Public) {
+                pub    = true;
+                result = next_token(lexer);
+                if (!result) return { result.error };
+            } else if (result->type == token::Private) {
+                result = next_token(lexer);
+                if (!result) return { result.error };
+            }
+
+            if (result->type == token::Func) {
+                auto nameRes = next_token(lexer);
+                if (!nameRes) return nameRes.error;
+
+                furvm::function_sig signature;
+
+                result = next_token(lexer);
+                if (!result) return result.error;
+                while (result->type == token::Dolar) {
+                    result = eat_token(lexer, token::Identifier);
+                    if (!result) return result.error;
+                    if (auto it = types.find(std::string(result->value.string)); it != types.end()) {
+                        signature.params.push_back(it->second);
+                    } else {
+                        return { generator_error::UnknownType, "Unknown type "s + std::string(result->value.string) };
+                    }
+
+                    result = next_token(lexer);
+                    if (!result) return result.error;
+                }
+                if (result->type != token::EqSign) return result.error;
+
+                result = next_token(lexer);
+                if (!result) return result.error;
+                if (result->type == token::Dolar) {
+                    result = eat_token(lexer, token::Identifier);
+                    if (!result) return result.error;
+                    if (auto it = types.find(std::string(result->value.string)); it != types.end()) {
+                        signature.returnType = it->second;
+                    } else {
+                        return { generator_error::UnknownType, "Unknown type "s + std::string(result->value.string) };
+                    }
+
+                    result = next_token(lexer);
+                    if (!result) return result.error;
+                }
+
+                switch (result->type) {
+                case token::Sha256: {
+                    result = eat_token(lexer, token::Identifier);
+                    if (!result) return result.error;
+
+                    std::string name = std::string(nameRes->value.string);
+
+                    std::string labelName = std::string(result->value.string);
+                    std::size_t offset    = 0;
+                    if (auto it = labels.find(labelName); it != labels.end()) {
+                        offset = it->second.offset;
+                    } else {
+                        labels[labelName].functions.emplace_back(
+                            label_context::function_info{ std::move(name), std::move(signature), pub });
+                        return { generator_error::Success };
+                    }
+
+                    furvm::function_h handle =
+                        (pub ? mod.emplace_function(name, signature, offset) : mod.emplace_function(signature, offset));
+
+                    functions.emplace(std::make_pair(name, std::move(signature)), handle);
+
+                    handle.dispatch();
+                    return { generator_error::Success };
+                }
+                case token::Native: {
+                    result = eat_token(lexer, token::Identifier);
+                    if (!result) return result.error;
+
+                    std::string nativeName = std::string(result->value.string);
+
+                    std::string name = std::string(nameRes->value.string);
+
+                    furvm::function_h handle = (pub ? mod.emplace_function(name, signature, std::move(nativeName))
+                                                    : mod.emplace_function(signature, std::move(nativeName)));
+
+                    functions.emplace(std::make_pair(name, std::move(signature)), handle);
+
+                    handle.dispatch();
+                    return { generator_error::Success };
+                }
+                case token::Import: {
+                    throw std::runtime_error("unimplemented");
+                }
+                default:
+                    return { generator_error::UnexpectedToken,
+                        "Unexpected token "s + token_type(result->type) +
+                            ", expected label name, `native`, or `import`" };
+                }
+            }
+
+            if (result->type == token::Type) {
+                auto nameRes = eat_token(lexer, token::Identifier);
+                if (!nameRes) return nameRes.error;
+
+                result = eat_token(lexer, token::EqSign);
+                if (!result) return result.error;
+
+                result = next_token(lexer);
+                if (!result) return result.error;
+                switch (result->type) {
+                case token::Import: {
+                    auto typeNameRes = eat_token(lexer, token::Identifier);
+                    if (!typeNameRes) return typeNameRes.error;
+                    return { generator_error::Success };
+                }
+                case token::Array: {
+                    result = eat_token(lexer, token::Dolar);
+                    if (!result) return result.error;
+
+                    auto typeNameRes = eat_token(lexer, token::Identifier);
+                    if (!typeNameRes) return typeNameRes.error;
+
+                    auto size = eat_token(lexer, token::Unsigned);
+                    if (!size) return size.error;
+
+                    furvm::mod_type_id innerId = 0;
+                    if (auto it = types.find(std::string(typeNameRes->value.string)); it != types.end()) {
+                        innerId = it->second.id();
+                    } else {
+                        return { generator_error::UnknownType,
+                            "Unknown type "s + std::string(typeNameRes->value.string) };
+                    }
+
+                    auto type = mod.emplace_type(innerId, size->value.uint);
+                    types.emplace(std::string(nameRes->value.string), type);
+                    type.dispatch();
+
+                    return { generator_error::Success };
+                }
+                default:
+                    return { generator_error::UnexpectedToken,
+                        "Unexpected token "s + token_type(result->type) +
+                            ", expected either type, `import`, or `array`" };
+                }
+            }
+
+            return { generator_error::UnexpectedToken,
+                "Unexpected token "s + token_type(result->type) + ", expected either `func` or `type`" };
+        }
+
+        case token::Push: {
+            auto result = eat_token(lexer, token::Dolar);
+            if (!result) return result.error;
+            auto typeName = eat_token(lexer, token::Identifier);
+            if (!typeName) return result.error;
+            auto it = types.find(std::string(typeName->value.string));
+            if (it == types.end())
+                return { generator_error::UnexpectedToken, "Unknown type "s + std::string(typeName->value.string) };
+            // TODO: Add support for signed integers
+            auto value = eat_token(lexer, token::Unsigned);
+            if (!value) return result.error;
+            auto type = it->second;
+            switch (type->type) {
+            case furvm::mod_type::S8: {
+                mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushS8));
+                mod.bytecode().push_back(value->value.uint & 0xFF);
+            } break;
+            case furvm::mod_type::U8: {
+                mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushU8));
+                mod.bytecode().push_back(value->value.uint & 0xFF);
+            } break;
+            case furvm::mod_type::S16: {
+                mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushS16));
+                mod.bytecode().push_back(value->value.uint & 0xFF);
+                mod.bytecode().push_back((value->value.uint >> 8) & 0xFF);
+            } break;
+            case furvm::mod_type::U16: {
+                mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushU16));
+                mod.bytecode().push_back(value->value.uint & 0xFF);
+                mod.bytecode().push_back((value->value.uint >> 8) & 0xFF);
+            } break;
+            case furvm::mod_type::S32: {
+                mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushS32));
+                mod.bytecode().push_back(value->value.uint & 0xFF);
+            } break;
+            case furvm::mod_type::U32: {
+                mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushU32));
+                mod.bytecode().push_back(value->value.uint & 0xFF);
+            } break;
+            default:
+                return { generator_error::UnexpectedToken, "Unexpected type "s + std::string(typeName->value.string) };
+            }
+            return { generator_error::Success };
+        }
+
+        case token::Array:
+        case token::Get:
+        case token::Set:
+        case token::Drop:
+        case token::Dup:
+        case token::Swap:
+        case token::Clone:
+        case token::Ref:
+        case token::Add:
+        case token::Sub:
+        case token::Mul:
+        case token::Div:
+        case token::Mod:
+        case token::Eq:
+        case token::Neq:
+        case token::Lt:
+        case token::Gt:
+        case token::Le:
+        case token::Ge:
+        case token::Ptrof:
+        case token::Sizeof:
+        case token::Lenof:
+        case token::Load:
+        case token::Store:
+        case token::Call:
+        case token::Jmp:
+        case token::Jnz:
+        case token::Ret: {
+            auto it = instructions.find(result->type);
+            assert(it != instructions.end());
+            mod.bytecode().push_back(static_cast<furvm::byte>(it->second.fur));
+            switch (it->second.arg) {
+            case instruction::None: break;
+            case instruction::Type: {
+                result = eat_token(lexer, token::Dolar);
+                if (!result) return result.error;
+                result = eat_token(lexer, token::Identifier);
+                if (!result) return result.error;
+                auto type = types.find(std::string(result->value.string));
+                if (type == types.end())
+                    return { generator_error::UnknownType, "Unknown type "s + std::string(result->value.string) };
+                auto id = type->second.id();
+                mod.bytecode().push_back((id >> 0) & 0xFF);
+                mod.bytecode().push_back((id >> 8) & 0xFF);
+                mod.bytecode().push_back((id >> 16) & 0xFF);
+                mod.bytecode().push_back((id >> 24) & 0xFF);
+            } break;
+            case instruction::Constant: {
+                assert(false); // TODO: Unimplemented
+            } break;
+            case instruction::Variable: {
+                result = eat_token(lexer, token::Percent);
+                if (!result) return result.error;
+                result = eat_token(lexer, token::Unsigned);
+                if (!result) return result.error;
+                std::uint16_t var = result->value.uint;
+                mod.bytecode().push_back((var >> 0) & 0xFF);
+                mod.bytecode().push_back((var >> 8) & 0xFF);
+            } break;
+            case instruction::Function: {
+                furvm::function_sig signature;
+                while ((result = next_token(lexer)).error.type == generator_error::Success &&
+                       result->type == token::Dolar) {
+                    result = eat_token(lexer, token::Identifier);
+                    if (!result) return result.error;
+                    auto type = types.find(std::string(result->value.string));
+                    if (type == types.end())
+                        return { generator_error::UnknownType, "Unknown type "s + std::string(result->value.string) };
+                    signature.params.push_back(type->second);
+                }
+                if (!result || result->type != token::Identifier) return result.error;
+                std::string name(result->value.string);
+
+                auto func = functions.find(std::make_pair(name, signature));
+                if (func == functions.end())
+                    return { generator_error::UnknownType, "Unknown type "s + std::string(result->value.string) };
+                auto id = func->second.id();
+                mod.bytecode().push_back((id >> 0) & 0xFF);
+                mod.bytecode().push_back((id >> 8) & 0xFF);
+            } break;
+            case instruction::Label: {
+                result = eat_token(lexer, token::Sha256);
+                if (!result) return result.error;
+                result = eat_token(lexer, token::Identifier);
+                if (!result) return result.error;
+                auto& label  = labels[std::string(result->value.string)];
+                auto  offset = label.offset;
+                if (offset == label_context::INVALID) {
+                    label.unknowns.push_back(mod.bytecode().size() + 1);
+                    mod.bytecode().push_back(0);
+                    return { generator_error::Success };
+                }
+                std::ptrdiff_t jmpOff = static_cast<std::ptrdiff_t>(offset - mod.bytecode().size() - 1);
+                if (jmpOff < std::numeric_limits<std::int8_t>::min() ||
+                    jmpOff > std::numeric_limits<std::int8_t>::max()) {
+                    assert(false); // TODO: Further jumps are not implemented
+                }
+                mod.bytecode().push_back(jmpOff);
+            } break;
+            }
+            return { generator_error::Success };
+        }
+
+        case token::Signed:
+        case token::Unsigned:
+        case token::Colon:
+        case token::Monkey:
+        case token::Dolar:
+        case token::Sha256:
+        case token::Percent:
+        case token::EqSign:
+        case token::Dot:
+        case token::Native:
+        case token::Import:
+        case token::Count: break;
+        }
+        return { generator_error::UnexpectedToken, "Unexpected token "s + token_type(result->type) };
+    }
+};
+
+} // namespace
+
+generator::result generator::generate(lexer lexer) {
+    mod_context     context;
+    generator_error error;
+    do {
+        error = context.generate(lexer);
+    } while (error.type == generator_error::Success);
+    if (error.type == generator_error::Eof) return { { generator_error::Success }, std::move(context.mod) };
+    return { error };
+}
+
+} // namespace furas

furas/src/lexer.cpp

@@ -0,0 +1,98 @@
+#include "furas/lexer.hpp"
+
+#include <cctype>
+#include <unordered_map>
+
+namespace furas {
+
+using namespace std::string_literals;
+
+token_r lexer::next_token() {
+    while (m_cursor < m_content.size() && std::isspace(m_content[m_cursor]) != 0) {
+        if (m_content[m_cursor] == '\n') {
+            m_lineStart = m_cursor + 1;
+            ++m_column;
+        }
+        ++m_cursor;
+    }
+
+    // TODO: Add support for single-line comments
+    // TODO: Add support for multi-line comments
+
+    if (m_cursor >= m_content.size()) return token_r{ lexer_error{ lexer_error::EndOfFile, location() } };
+
+    // TODO: Add support for negative integers (I am positive thanks to stasiu :v:)
+    // TODO: Add support for hexadecimal and binary numeric literals
+    if (std::isdigit(m_content[m_cursor]) != 0) {
+        std::uint64_t num = 0;
+        while (m_cursor < m_content.size() && std::isdigit(m_content[m_cursor]) != 0) {
+            num *= 10;
+            num += m_content[m_cursor++] - '0';
+        }
+        return { num };
+    }
+
+    static std::unordered_map<std::string_view, enum token::type> s_tokens = {
+        { "func", token::Func },
+        { "type", token::Type },
+        { "native", token::Native },
+        { "import", token::Import },
+        { "public", token::Public },
+        { "private", token::Private },
+
+        { "push", token::Push },
+        { "array", token::Array },
+        { "get", token::Get },
+        { "set", token::Set },
+        { "drop", token::Drop },
+        { "dup", token::Dup },
+        { "swap", token::Swap },
+        { "clone", token::Clone },
+        { "ref", token::Ref },
+        { "add", token::Add },
+        { "sub", token::Sub },
+        { "mul", token::Mul },
+        { "div", token::Div },
+        { "mod", token::Mod },
+        { "eq", token::Eq },
+        { "neq", token::Neq },
+        { "lt", token::Lt },
+        { "gt", token::Gt },
+        { "le", token::Le },
+        { "ge", token::Ge },
+        { "ptrof", token::Ptrof },
+        { "sizeof", token::Sizeof },
+        { "lenof", token::Lenof },
+        { "load", token::Load },
+        { "store", token::Store },
+        { "call", token::Call },
+        { "jmp", token::Jmp },
+        { "jnz", token::Jnz },
+        { "ret", token::Ret },
+    };
+
+    if (std::isalnum(m_content[m_cursor]) != 0) {
+        std::size_t begin = m_cursor++;
+        while (m_cursor < m_content.size() && (std::isalnum(m_content[m_cursor]) != 0 || m_content[m_cursor] == '_'))
+            ++m_cursor;
+        std::string_view str = m_content.substr(begin, m_cursor - begin);
+        if (auto it = s_tokens.find(str); it != s_tokens.end()) return { it->second };
+        return { token::Identifier, str };
+    }
+
+    switch (m_content[m_cursor]) {
+    case '@': ++m_cursor; return { token::Monkey };
+    case '$': ++m_cursor; return { token::Dolar };
+    case '#': ++m_cursor; return { token::Sha256 };
+    case '%': ++m_cursor; return { token::Percent };
+    case '=': ++m_cursor; return { token::EqSign };
+    case '.': ++m_cursor; return { token::Dot };
+    case ':': ++m_cursor; return { token::Colon };
+    default:
+        return token_r{
+            lexer_error{ lexer_error::UnknownCharacter, location(), "Unknown character '"s + m_content[m_cursor] + "'" }
+        };
+    }
+}
+
+} // namespace furas

furas/src/main.cpp

@@ -0,0 +1,39 @@
+#include "furas/gen.hpp"
+#include "furas/lexer.hpp"
+
+#include <fstream>
+#include <furvm/module.hpp>
+#include <iostream>
+
+int main(int argc, char** argv) { // NOLINT
+    if (argc < 2) {
+        std::cerr << "feed me more arguments daddy >_<\n";
+        return 1;
+    }
+    if (argc > 2) {
+        std::cerr << "too much O_O\n";
+        return 1;
+    }
+
+    const char* filepath = argv[1];
+
+    std::ifstream file(filepath, std::ios::binary | std::ios::ate | std::ios::in);
+    if (!file.is_open()) {
+        std::cerr << "file won't open >~<\n";
+        return 1;
+    }
+    std::string content;
+    content.resize(file.tellg());
+    file.seekg(0);
+    file.read(content.data(), static_cast<std::streamsize>(content.size()));
+
+    auto result = furas::generator::generate(furas::lexer(filepath, content));
+    if (result.error.type != furas::generator_error::Success) {
+        std::cerr << result.error.message << '\n';
+        return 1;
+    }
+
+    result.mod.serialize(std::cout);
+
+    return 0;
+}

furc/src/back/furvm.cpp

@@ -2,6 +2,7 @@
 
 #include "furlang/ir/function.hpp"
 #include "furlang/ir/instruction.hpp"
+#include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 
 #include <furvm/instruction.hpp>
@@ -20,12 +21,14 @@ furvm::mod furvm_generator::generate(furlang::ir::mod& mod) {
 }
 
 void furvm_generator::generate_function(furvm::mod& mod, const furlang::ir::function& function) {
+    furvm::function_sig signature; // TODO: Complete
+
     switch (function.type()) {
     case furlang::ir::function_t::Normal: {
         if (function.access() == furlang::ir::function_access_t::Public)
-            mod.emplace_function(function.name(), function.param_count(), mod.bytecode().size()).dispatch();
+            mod.emplace_function(function.name(), std::move(signature), mod.bytecode().size()).dispatch();
         else
-            mod.emplace_function_private(function.name(), function.param_count(), mod.bytecode().size()).dispatch();
+            mod.emplace_function(std::move(signature), mod.bytecode().size()).dispatch();
 
         function_context ctx;
         for (furlang::ir::block_index idx = 0; idx < function.blocks().size(); ++idx) {
@@ -48,9 +51,9 @@ void furvm_generator::generate_function(furvm::mod& mod, const furlang::ir::func
     } break;
     case furlang::ir::function_t::Native: {
         if (function.access() == furlang::ir::function_access_t::Public)
-            mod.emplace_function(function.name(), function.param_count(), function.name()).dispatch();
+            mod.emplace_function(function.name(), std::move(signature), function.name()).dispatch();
         else
-            mod.emplace_function_private(function.name(), function.param_count(), function.name()).dispatch();
+            mod.emplace_function(std::move(signature), function.name()).dispatch();
     } break;
     }
 }
@@ -140,17 +143,13 @@ void furvm_generator::generate_instruction(furvm::mod& mod,
         generate_jump(mod, ctx, branch.else_block(), false);
     } break;
     case furlang::ir::instruction_t::Return: {
-        if (instr.sources().empty()) {
         mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::Return));
-        } else {
-            mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::ReturnValue));
-        }
     } break;
     case furlang::ir::instruction_t::Call: {
         const auto& call = dynamic_cast<const furlang::ir::call_instruction&>(instr);
 
         // TODO: Implement a queue for unknown functions
-        furvm::function_id func = mod.get_function_id(call.name());
+        furvm::function_id func = mod.function_at(call.name(), furvm::function_sig{}).id(); // TODO: Complete
         mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::Call));
         mod.bytecode().push_back((func >> 0) & 0xFF);
         mod.bytecode().push_back((func >> 8) & 0xFF);
@@ -171,7 +170,7 @@ void furvm_generator::generate_operand(furvm::mod& mod, function_context& ctx, c
         static_assert(sizeof(var) == 2, "sizeof(furvm::variable_t) has changed");
     } break;
     case furlang::ir::operand_t::Integer: {
-        mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushB2I));
+        mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::PushS32));
         mod.bytecode().push_back(operand.integer());
     } break;
     case furlang::ir::operand_t::Variable:

furc/src/main.cpp

@@ -71,7 +71,7 @@ int main(void) {
             [](furvm::executor& executor) { std::cout << executor.load_thing(0)->integer() << '\n'; });
 
         furvm::executor_h executor = context->emplace_executor(context);
-        executor->push_frame(furvmMod, *furvmMod->function_at("main"));
+        executor->push_frame(furvmMod, *furvmMod->function_at("main", furvm::function_sig{}));
 
         std::cout << "--- Interpreting:\n";
 

furlang/include/furlang/utility/hash.hpp

@@ -0,0 +1,47 @@
+#ifndef FURLANG_UTILITY_HASH_HPP
+#define FURLANG_UTILITY_HASH_HPP
+
+#include <cstddef>
+#include <functional>
+
+namespace furlang {
+namespace utility {
+
+// Source - https://stackoverflow.com/a/27952689
+// Posted by Yakk - Adam Nevraumont, modified by community. See post 'Timeline' for change history
+// Retrieved 2026-07-07, License - CC BY-SA 4.0
+static inline std::size_t hash_combine(std::size_t lhs, std::size_t rhs) {
+    if constexpr (sizeof(std::size_t) >= 8) {
+        lhs ^= rhs + 0x517cc1b727220a95 + (lhs << 6) + (lhs >> 2);
+    } else {
+        lhs ^= rhs + 0x9e3779b9 + (lhs << 6) + (lhs >> 2);
+    }
+
+    return lhs;
+}
+
+// Source - https://stackoverflow.com/a/20602159
+// Posted by Casey, modified by community. See post 'Timeline' for change history
+// Retrieved 2026-07-07, License - CC BY-SA 3.0
+template <typename T, typename U, typename FirstHash = std::hash<T>, typename SecondHash = std::hash<U>>
+struct pair_hash {
+    std::size_t operator()(const std::pair<T, U>& pair) const {
+        return hash_combine(FirstHash()(pair.first), SecondHash()(pair.second));
+    }
+};
+
+template <typename T, typename Hash = std::hash<T>>
+struct vector_hash {
+    std::size_t operator()(const std::vector<T>& vec) const {
+        std::size_t seed = 0;
+        for (const auto& element : vec) {
+            hash_combine(seed, Hash()(element));
+        }
+        return seed;
+    }
+};
+
+} // namespace utility
+} // namespace furlang
+
+#endif // FURLANG_UTILITY_HASH_HPP

furvm/include/furvm/context.hpp

@@ -21,7 +21,8 @@ public:
     /**
      * @brief Constructs a context.
      */
-    context();
+    context()
+      : m_thingAllocator(m_thingArena) {}
 
     ~context() = default;
 
@@ -124,6 +125,8 @@ public:
      * @return The thing allocator.
      */
     thing_allocator<std::byte> thing_alloc() const { return m_thingAllocator; }
+
+    thing_type_store& thing_type_store() { return m_thingTypeStore; }
 private:
     handle_container<mod_h>      m_modules;
     handle_container<thing_h>    m_things;
@@ -131,6 +134,7 @@ private:
 
     furlang::arena             m_thingArena;
     thing_allocator<std::byte> m_thingAllocator;
+    class thing_type_store     m_thingTypeStore;
 };
 
 } // namespace furvm

furvm/include/furvm/detail/handle.hpp

@@ -1,6 +1,7 @@
 #ifndef FURVM_DETAIL_HANDLE_HPP
 #define FURVM_DETAIL_HANDLE_HPP
 
+#include <functional>
 #include <type_traits>
 
 namespace furvm {
@@ -27,6 +28,11 @@ struct header_has_refcount<Header,
 template <typename Header>
 static constexpr auto header_has_refcount_v = header_has_refcount<Header>::value;
 
+template <typename Handle, typename IdHash = std::hash<typename Handle::id_type>>
+struct handle_hash {
+    std::size_t operator()(const Handle& handle) const { return IdHash{}(handle.id()); }
+};
+
 } // namespace detail
 } // namespace furvm
 

furvm/include/furvm/executor.hpp

@@ -5,6 +5,7 @@
 #include "furvm/module.hpp" // IWYU pragma: keep
 #include "furvm/thing.hpp"  // IWYU pragma: keep
 
+#include <optional>
 #include <stack>
 #include <utility>
 #include <vector>
@@ -40,6 +41,7 @@ public:
         std::size_t position;  /**< Cursor to a current instruction in the bytecode. */
         std::size_t stackBase; /**< Snapshot of the stack size before this frame. */
 
+        thing_type*          returnType; /**< Return type. */
         std::vector<thing_h> variables;  /**< Frame variables. */
     };
 public:
@@ -164,6 +166,10 @@ public:
      * @brief Executes next instruction.
      */
     void step();
+private:
+    thing_type thing_type_impl(mod_h mod, mod_type type) const;
+
+    thing_type* thing_type(const mod_h& mod, const mod_type& type) const;
 private:
     executor_flags m_flags{}; // NOLINT(bugprone-invalid-enum-default-initialization)
     context_p      m_context;

furvm/include/furvm/function.hpp

@@ -1,14 +1,17 @@
 #ifndef FURVM_FUNCTION_HPP
 #define FURVM_FUNCTION_HPP
 
+#include "furlang/utility/hash.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/handle.hpp" // IWYU pragma: keep
 
 #include <cstdint>
+#include <optional>
 #include <stdexcept>
 #include <string>
 #include <type_traits>
 #include <utility>
+#include <vector>
 
 namespace furvm {
 
@@ -31,33 +34,43 @@ struct import_function {
     function_id function;
 };
 
+/**
+ * @brief Function signature.
+ */
+struct function_sig {
+    std::vector<mod_type_h>   params;
+    std::optional<mod_type_h> returnType;
+
+    bool operator==(const function_sig& rhs) const { return params == rhs.params; }
+
+    bool operator!=(const function_sig& rhs) const { return !this->operator==(rhs); }
+};
+
 class function {
 public:
     /**
      * @brief Constructs a normal function.
      *
-     * @param name Name of the function.
-     * @param paramCount Paremeter count.
+     * @param signature Function's signature.
      * @param position Offset in bytecode of the function.
      */
-    template <typename Name>
-    function(Name&& name, std::uint32_t paramCount, bytecode_pos position)
-      : m_name(std::forward<Name>(name)), m_type(function_t::Normal), m_paramCount(paramCount), m_value(position) {}
+    template <typename SigFwd, typename = std::enable_if_t<std::is_constructible_v<function_sig, SigFwd>>>
+    function(SigFwd&& signature, bytecode_pos position)
+      : m_type(function_t::Normal), m_signature(std::forward<SigFwd>(signature)), m_value(position) {}
 
     /**
      * @brief Constructs a native function.
      *
-     * @param name Name of the function.
-     * @param paramCount Paremeter count.
+     * @param signature Function's signature.
      * @param native Native function tag.
      */
-    template <typename Name,
+    template <typename SigFwd,
         typename Native,
-        typename = std::enable_if_t<std::is_constructible_v<native_function, Native>>>
-    function(Name&& name, std::uint32_t paramCount, Native&& native)
-      : m_name(std::forward<Name>(name)),
-        m_type(function_t::Native),
-        m_paramCount(paramCount),
+        typename = std::enable_if_t<std::is_constructible_v<native_function, Native> &&
+                                    std::is_constructible_v<function_sig, SigFwd>>>
+    function(SigFwd&& signature, Native&& native)
+      : m_type(function_t::Native),
+        m_signature(std::forward<SigFwd>(signature)),
         m_value(std::forward<Native>(native)) {}
 
     /**
@@ -68,7 +81,7 @@ public:
      */
     template <typename ModFwd, typename = std::enable_if_t<std::is_constructible_v<mod_id, ModFwd>>>
     function(ModFwd&& mod, function_id function)
-      : m_type(function_t::Import), m_paramCount(0), m_value(import_function{ std::forward<ModFwd>(mod), function }) {}
+      : m_type(function_t::Import), m_signature(), m_value(import_function{ std::forward<ModFwd>(mod), function }) {}
 
     /**
      * @brief Constructs an import function.
@@ -103,13 +116,6 @@ public:
      */
     function& operator=(const function&);
 public:
-    /**
-     * @brief Returns a name of this function.
-     *
-     * @return The name.
-     */
-    constexpr const std::string& name() const { return m_name; }
-
     /**
      * @brief Returns a type of this function.
      *
@@ -118,11 +124,11 @@ public:
     constexpr function_t type() const { return m_type; }
 
     /**
-     * @brief Returns this function's parameter count.
+     * @brief Returns this function's signature.
      *
-     * @return The parameter count.
+     * @return The signature.
      */
-    constexpr std::uint32_t param_count() const { return m_paramCount; }
+    function_sig signature() const { return m_signature; }
 public:
     /**
      * @brief Returns normal function's value.
@@ -154,9 +160,8 @@ public:
         return m_value.imp;
     }
 private:
-    std::string   m_name;
     function_t   m_type;
-    std::uint32_t m_paramCount;
+    function_sig m_signature;
 
     union value {
         std::size_t     position = 0;
@@ -184,6 +189,14 @@ private:
     } m_value;
 };
 
+namespace detail {
+
+struct function_sig_hash {
+    std::size_t operator()(const function_sig& signature) const;
+};
+
+} // namespace detail
+
 } // namespace furvm
 
 #endif // FURVM_FUNCTION_HPP

furvm/include/furvm/fwd.hpp

@@ -115,6 +115,12 @@ using function_h = handle<function, refcount_header<function_id>>;
 
 // module.hpp
 
+struct mod_type;
+
+using mod_type_id = std::uint32_t;
+
+using mod_type_h = handle<mod_type, generic_header<mod_type_id>>;
+
 /**
  * @class mod
  * @brief Module.
@@ -138,34 +144,20 @@ using mod_id = std::string;
  */
 using mod_h = handle<mod, refcount_header<mod_id>>;
 
+// thing_allocator.hpp
+
+template <typename T>
+class thing_allocator;
+
 // thing.hpp
 
-/**
- * @enum type_t
- * @brief Type of the thing's type.
- */
-enum class type_t : std::uint32_t;
-
-/**
- * @struct type
- * @brief Thing type.
- */
-struct type;
-
-using type_p = std::shared_ptr<type>;
-
-using type_id = std::uint32_t;
-
-using type_h = handle<type_p, generic_header<type_id>>;
-
 /**
  * @class bad_thing_access
  * @brief Bad thing access exception.
  */
 class bad_thing_access;
 
-template <typename T>
-class thing_allocator;
+using thing_type_id = std::uint32_t;
 
 /**
  * @class thing

furvm/include/furvm/handle.hpp

@@ -237,6 +237,10 @@ public:
      * @brief Invalidates the handle without releasing.
      */
     void dispatch() { m_value = nullptr; }
+public:
+    bool operator==(const handle& rhs) const { return m_value == rhs.m_value; }
+
+    bool operator!=(const handle& rhs) const { return !this->operator==(rhs); }
 private:
     pair_type* m_value = nullptr;
 };

furvm/include/furvm/instruction.hpp

@@ -12,11 +12,34 @@ enum class instruction_t : byte {
     NoOperation = 0,
 
     /**
-     * @brief Pushes an integer from a byte onto the stack.
-     *
-     * Pushes an integer constructed from a next byte onto the stack.
+     * @brief Pushes an s8 integer from a byte onto the stack.
      */
-    PushB2I,
+    PushS8,
+
+    /**
+     * @brief Pushes an u8 integer from a byte onto the stack.
+     */
+    PushU8,
+
+    /**
+     * @brief Pushes an s16 integer from two byte onto the stack.
+     */
+    PushS16,
+
+    /**
+     * @brief Pushes an u16 integer from two byte onto the stack.
+     */
+    PushU16,
+
+    /**
+     * @brief Pushes an s32 integer from a byte onto the stack.
+     */
+    PushS32,
+
+    /**
+     * @brief Pushes an u32 integer from a byte onto the stack.
+     */
+    PushU32,
 
     /**
      * @brief Pushes a constant onto the stack.
@@ -25,6 +48,24 @@ enum class instruction_t : byte {
      */
     PushConstant,
 
+    /**
+     * @brief Pushes a new array onto the stack.
+     *
+     * Type is the next 4 bytes in little-endian.
+     * If the type is dynamic the array's size will be popped off of the stack.
+     */
+    Array,
+
+    /**
+     * @brief Pushes an element from an array onto the stack.
+     */
+    Get,
+
+    /**
+     * @brief Sets an array element.
+     */
+    Set,
+
     /**
      * @brief Pops top element from the stack.
      */
@@ -35,6 +76,11 @@ enum class instruction_t : byte {
      */
     Duplicate,
 
+    /**
+     * @brief Swaps two top elements of the stack.
+     */
+    Swap,
+
     /**
      * @brief Clones top element on the stack.
      */
@@ -112,6 +158,11 @@ enum class instruction_t : byte {
      */
     Sizeof,
 
+    /**
+     * @brief Pushes a length of popped-off thing onto the stack.
+     */
+    Lengthof,
+
     /**
      * @brief Pushes a variable onto the stack.
      *
@@ -152,11 +203,6 @@ enum class instruction_t : byte {
      * @brief Pops the current call frame.
      */
     Return,
-
-    /**
-     * @brief Pops the current call frame and pushes the first element from the previous stack onto the new stack.
-     */
-    ReturnValue,
 };
 
 struct instruction {

furvm/include/furvm/module.hpp

@@ -1,10 +1,10 @@
 #ifndef FURVM_MODULE_HPP
 #define FURVM_MODULE_HPP
 
+#include "furlang/utility/hash.hpp"
 #include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/handle.hpp"
-#include "furvm/type.hpp" // IWYU pragma: keep
 
 #include <functional>
 #include <istream>
@@ -17,6 +17,129 @@
 
 namespace furvm {
 
+struct mod_type {
+    struct array {
+        mod_type_id typeId;
+        std::size_t size;
+    };
+
+    struct imprt {
+        mod_id      modId;
+        mod_type_id typeId;
+    };
+
+    enum type {
+        S8 = 0,
+        S16,
+        S32,
+        S64,
+        U8,
+        U16,
+        U32,
+        U64,
+        Ptr,
+        Ref,
+        Array,
+
+        Import,
+        Count,
+    } type;
+    union value {
+        std::nullptr_t null = nullptr;
+        mod_type_id    typeRef;
+        array          array;
+        imprt          imprt;
+
+        value() = default;
+
+        value(mod_type_id id)
+          : typeRef(id) {}
+
+        value(mod_type_id id, std::size_t size)
+          : array({}) {
+            array.typeId = id;
+            array.size   = size;
+        }
+
+        template <typename ModIdFwd, typename = std::enable_if_t<std::is_constructible_v<mod_id, ModIdFwd>>>
+        value(ModIdFwd&& modId, mod_type_id typeId)
+          : imprt({}) {
+            imprt.modId  = std::forward<ModIdFwd>(modId);
+            imprt.typeId = typeId;
+        }
+
+        ~value() {}
+
+        value(value&& other)                 = delete;
+        value& operator=(value&& other)      = delete;
+        value(const value& other)            = delete;
+        value& operator=(const value& other) = delete;
+    } value;
+
+    mod_type(enum type type)
+      : type(type) {}
+
+    mod_type(enum type type, mod_type_id typeRef)
+      : type(type), value(typeRef) {}
+
+    mod_type(mod_type_id id, std::size_t size)
+      : type(Array), value(id, size) {}
+
+    template <typename ModIdFwd, typename = std::enable_if_t<std::is_constructible_v<mod_id, ModIdFwd>>>
+    mod_type(ModIdFwd&& modId, mod_type_id typeId)
+      : type(Import), value(std::forward<ModIdFwd>(modId), typeId) {}
+
+    ~mod_type() {
+        switch (type) {
+        case Array: value.array.~array(); break;
+        case Import: value.imprt.~imprt(); break;
+        default: break;
+        }
+    }
+
+    mod_type(mod_type&& other) noexcept
+      : type(other.type) {
+        switch (type) {
+        case Array: new (&value.array) array(other.value.array); break;
+        case Import: new (&value.imprt) imprt(std::move(other.value.imprt)); break;
+        default: break;
+        }
+        other.type = Count;
+    }
+
+    mod_type& operator=(mod_type&& other) noexcept {
+        if (this == &other) return *this;
+        type = other.type;
+        switch (type) {
+        case Array: new (&value.array) array(other.value.array); break;
+        case Import: new (&value.imprt) imprt(std::move(other.value.imprt)); break;
+        default: break;
+        }
+        other.type = Count;
+        return *this;
+    }
+
+    mod_type(const mod_type& other)
+      : type(other.type) {
+        switch (type) {
+        case Array: new (&value.array) array(other.value.array); break;
+        case Import: new (&value.imprt) imprt(other.value.imprt); break;
+        default: break;
+        }
+    }
+
+    mod_type& operator=(const mod_type& other) {
+        if (this == &other) return *this;
+        type = other.type;
+        switch (type) {
+        case Array: new (&value.array) array(other.value.array); break;
+        case Import: new (&value.imprt) imprt(other.value.imprt); break;
+        default: break;
+        }
+        return *this;
+    }
+};
+
 class mod {
     friend class function;
     friend class serializer;
@@ -86,51 +209,38 @@ public:
     function_h emplace_function(Args&&... args) {
         function_h function;
         if constexpr (std::is_constructible_v<class function, Args...>) {
-            function = m_functions.emplace_back(std::forward<Args>(args)...);
+            function = std::move(m_functions.emplace_back(std::forward<Args>(args)...));
         } else {
-            function = m_functions.emplace(std::forward<Args>(args)...);
+            function = std::move(m_functions.emplace(std::forward<Args>(args)...));
         }
-
-        m_functionMap[function->name()]     = function.id();
-        m_publicFunctions[function->name()] = function.id();
         return std::move(function);
     }
 
     /**
      * @brief Emplaces a function in the module's function container.
      *
-     * Emplaces the function in module's function container and name to function map .
+     * Emplaces the function in module's function container and name to function map.
      *
+     * @param name Name of the function.
      * @param args Arguments forwarded into the container's emplace_back function.
      * @return A handle to the emplaced function.
      */
-    template <typename... Args>
-    function_h emplace_function_private(Args&&... args) {
-        function_h function             = m_functions.emplace_back(std::forward<Args>(args)...);
-        m_functionMap[function->name()] = function.id();
+    template <typename NameFwd,
+        typename... Args,
+        typename = std::enable_if_t<std::is_constructible_v<std::string, NameFwd>>>
+    function_h emplace_function(NameFwd&& name, Args&&... args) {
+        function_h function;
+        if constexpr (std::is_constructible_v<class function, Args...>) {
+            function = std::move(m_functions.emplace_back(std::forward<Args>(args)...));
+        } else {
+            function = std::move(m_functions.emplace(std::forward<Args>(args)...));
+        }
+        auto pair                       = std::make_pair(std::forward<NameFwd>(name), function->signature());
+        m_functionMap[function.id()]    = pair;
+        m_functionSigs[std::move(pair)] = function.id();
         return std::move(function);
     }
 
-    /**
-     * @brief Inserts a function in the module's function container.
-     *
-     * @param function Function to insert.
-     */
-    template <typename Function>
-    auto push_back(Function&& function) {
-        return emplace_function(std::forward<Function>(function));
-    }
-
-    /**
-     * @brief Inserts a function in the module's function container.
-     *
-     * @param function Function to insert.
-     */
-    template <typename Function>
-    auto push_back_private(Function&& function) {
-        return emplace_function_private(std::forward<Function>(function));
-    }
-
     /**
      * @brief Returns a function from the module.
      *
@@ -153,31 +263,13 @@ public:
      * @param name Name of the function.
      * @return A handle to the function.
      */
-    template <typename NameFwd, typename = std::enable_if_t<std::is_constructible_v<std::string, NameFwd>>>
-    auto function_at(NameFwd&& name) {
-        return function_at(m_publicFunctions.at(std::forward<NameFwd>(name)));
-    }
-
-    /**
-     * @brief Returns a function from the module.
-     *
-     * @param name Name of the function.
-     * @return A handle to the function.
-     */
-    template <typename NameFwd, typename = std::enable_if_t<std::is_constructible_v<std::string, NameFwd>>>
-    auto function_at(NameFwd&& name) const {
-        return function_at(m_publicFunctions.at(std::forward<NameFwd>(name)));
-    }
-
-    /**
-     * @brief Returns an id of a function from the module.
-     *
-     * @param name Name of the function.
-     * @return An id of the function.
-     */
-    template <typename NameFwd>
-    auto get_function_id(NameFwd&& name) {
-        return m_functionMap.at(std::forward<NameFwd>(name));
+    template <typename NameFwd,
+        typename SigFwd,
+        typename = std::enable_if_t<std::is_constructible_v<std::string, NameFwd> &&
+                                    std::is_constructible_v<function_sig, SigFwd>>>
+    auto function_at(NameFwd&& name, SigFwd&& signature) {
+        return function_at(
+            m_functionSigs.at(std::make_pair<>(std::forward<NameFwd>(name), std::forward<SigFwd>(signature))));
     }
 
     /**
@@ -185,7 +277,13 @@ public:
      *
      * @param id Identifier of the function.
      */
-    void erase_function(function_id id) { m_functions.erase(id); }
+    void erase_function(function_id id) {
+        m_functions.erase(id);
+        if (auto it = m_functionMap.find(id); it != m_functionMap.end()) {
+            m_functionSigs.erase(it->second);
+            m_functionMap.erase(it);
+        }
+    }
 public:
     template <typename NameFwd, typename Func>
     void set_native_function(NameFwd&& name, Func&& func) {
@@ -205,7 +303,7 @@ public:
      */
     template <typename... Args>
     auto emplace_type(Args&&... args) {
-        if constexpr (std::is_constructible_v<type_p, Args...>) {
+        if constexpr (std::is_constructible_v<mod_type, Args...>) {
             return m_types.emplace_back(std::forward<Args>(args)...);
         } else {
             return m_types.emplace(std::forward<Args>(args)...);
@@ -262,11 +360,14 @@ public:
 private:
     bytecode_t m_bytecode;
 
-    std::unordered_map<std::string, function_id> m_functionMap;
-    std::unordered_map<std::string, function_id> m_publicFunctions;
+    using pair_type = std::pair<std::string, function_sig>;
+    using pair_hash =
+        furlang::utility::pair_hash<std::string, function_sig, std::hash<std::string>, detail::function_sig_hash>;
+    std::unordered_map<pair_type, function_id, pair_hash> m_functionSigs;
+    std::unordered_map<function_id, pair_type>            m_functionMap;
     handle_container<function_h>                          m_functions;
 
-    handle_container<type_h> m_types;
+    handle_container<mod_type_h> m_types;
 
     std::unordered_map<std::string, native_function> m_nativeFunctions;
 };

furvm/include/furvm/thing.hpp

@@ -1,29 +1,209 @@
 #ifndef FURVM_THING_HPP
 #define FURVM_THING_HPP
 
+#include "furlang/arena.hpp"
+#include "furlang/utility/hash.hpp"
 #include "furvm/exceptions.hpp"
 #include "furvm/fwd.hpp"
-#include "furvm/module.hpp"
-#include "furvm/type.hpp"
+#include "furvm/thing_allocator.hpp" // IWYU pragma: keep
 
 #include <algorithm>
 #include <cstddef>
 #include <cstring>
 #include <functional>
-#include <memory>
+#include <limits>
 #include <new>
 #include <stdexcept>
+#include <type_traits>
+#include <unordered_map>
 #include <utility>
 
 namespace furvm {
 
+struct thing_type {
+    using s8  = std::int8_t;
+    using s16 = std::int16_t;
+    using s32 = std::int32_t;
+    using s64 = std::int64_t;
+    using u8  = std::uint8_t;
+    using u16 = std::uint16_t;
+    using u32 = std::uint32_t;
+    using u64 = std::uint64_t;
+
+    struct array {
+        thing_type* type;
+        std::size_t size;
+    };
+
+    enum type { // NOLINT
+        S8 = 0,
+        S16,
+        S32,
+        S64,
+        U8,
+        U16,
+        U32,
+        U64,
+        Ptr,
+        Ref,
+        Array,
+
+        Count,
+    } type;
+    union value {
+        std::nullptr_t null = nullptr;
+        thing_type*    typeRef;
+        array          array;
+
+        value() = default;
+
+        value(thing_type* type)
+          : typeRef(type) {}
+
+        value(thing_type* type, std::size_t size)
+          : array({}) {
+            array.type = type;
+            array.size = size;
+        }
+    } value;
+
+    static constexpr thing_type_id INVALID_ID = std::numeric_limits<thing_type_id>::max();
+
+    thing_type_id id = INVALID_ID;
+
+    bool operator==(const thing_type& other) const {
+        if (type != other.type) return false;
+        switch (type) {
+        case S8:
+        case S16:
+        case S32:
+        case S64:
+        case U8:
+        case U16:
+        case U32:
+        case U64: return true;
+        case Ptr:
+        case Ref: return *value.typeRef == *other.value.typeRef;
+        case Array: return *value.array.type == *other.value.array.type && value.array.size == other.value.array.size;
+        case Count: break;
+        }
+        return false;
+    }
+
+    bool operator!=(const thing_type& other) const { return !this->operator==(other); }
+
+    static bool is_primitive(enum type type) {
+        switch (type) {
+        case S8:
+        case S16:
+        case S32:
+        case S64:
+        case U8:
+        case U16:
+        case U32:
+        case U64: return true;
+        case Ptr:
+        case Ref:
+        case Array: return false;
+        case Count: break;
+        }
+        throw std::runtime_error("unreachable");
+    }
+
+    static std::size_t primitive_size(enum type type) {
+        switch (type) {
+        case thing_type::S8: return sizeof(s8);
+        case thing_type::S16: return sizeof(s16);
+        case thing_type::S32: return sizeof(s32);
+        case thing_type::S64: return sizeof(s64);
+        case thing_type::U8: return sizeof(u8);
+        case thing_type::U16: return sizeof(u16);
+        case thing_type::U32: return sizeof(u32);
+        case thing_type::U64: return sizeof(u64);
+        case Ptr:
+        case Ref:
+        case Array: return 0;
+        case Count: break;
+        }
+        throw std::runtime_error("unreachable");
+    }
+};
+
+namespace detail {
+
+struct thing_type_hash {
+    std::size_t operator()(const thing_type& type) const {
+        std::size_t seed = std::hash<decltype(type.type)>{}(type.type);
+        switch (type.type) {
+        case thing_type::S8:
+        case thing_type::S16:
+        case thing_type::S32:
+        case thing_type::S64:
+        case thing_type::U8:
+        case thing_type::U16:
+        case thing_type::U32:
+        case thing_type::U64: return seed;
+        case thing_type::Ptr:
+        case thing_type::Ref: return furlang::utility::hash_combine(seed, thing_type_hash{}(*type.value.typeRef));
+        case thing_type::Array:
+            seed = furlang::utility::hash_combine(seed, thing_type_hash{}(*type.value.array.type));
+            seed = furlang::utility::hash_combine(seed,
+                std::hash<decltype(type.value.array.size)>{}(type.value.array.size));
+            return seed;
+        case thing_type::Count: break;
+        }
+        throw std::runtime_error("unreachable");
+    }
+};
+
+} // namespace detail
+
+class thing_type_store {
+public:
+    thing_type* insert(thing_type& type) {
+        if (auto it = m_typeMap.find(type); it != m_typeMap.end()) return m_map[type.id = it->second];
+        if (type.id == thing_type::INVALID_ID) type.id = m_counter++;
+
+        thing_type* ptr = m_arena.allocate<thing_type>(type);
+        m_map[type.id]  = ptr;
+        m_typeMap[type] = type.id;
+        return ptr;
+    }
+
+    thing_type* insert(const thing_type& type) {
+        if (auto it = m_typeMap.find(type); it != m_typeMap.end()) return m_map[it->second];
+
+        thing_type_id id  = m_counter++;
+        thing_type*   ptr = m_arena.allocate<thing_type>(type);
+        m_map[id]         = ptr;
+        m_typeMap[type]   = id;
+        return ptr;
+    }
+
+    thing_type* at(thing_type_id id) const {
+        if (auto it = m_map.find(id); it != m_map.end()) return it->second;
+        return nullptr;
+    }
+private:
+    furlang::arena                                                         m_arena;
+    std::unordered_map<thing_type_id, thing_type*>                         m_map;
+    std::unordered_map<thing_type, thing_type_id, detail::thing_type_hash> m_typeMap;
+    thing_type_id                                                          m_counter = 0;
+};
+
 template <template <typename> typename Allocator>
 class thing final {
     friend class executor;
 public:
     using allocator_type = Allocator<std::byte>; /**< Allocator type. */
-
-    using mod_container = std::shared_ptr<handle_container<mod_h>>;
+public:
+    union array {
+        std::byte flat[];
+        struct {
+            std::size_t size;
+            std::byte*  data;
+        } dynamic;
+    };
 public:
     /**
      * @brief Constructs a thing.
@@ -31,17 +211,9 @@ public:
      * @param type Thing type.
      * @param allocator Allocator for the thing's data.
      */
-    thing(const type& type, const mod_container& modules = nullptr, const allocator_type& allocator = {})
-      : thing(std::make_shared<class type>(type), modules, allocator) {}
-
-    /**
-     * @brief Constructs a thing.
-     *
-     * @param type Thing type.
-     * @param allocator Allocator for the thing's data.
-     */
-    thing(const type_p& type, const mod_container& modules = nullptr, const allocator_type& allocator = {})
-      : m_type(type), m_size(compute_size(resolve_type(type, modules))), m_modules(modules), m_allocator(allocator) {
+    thing(const thing_type& type, const allocator_type& allocator = {})
+      : m_type(type), m_size(compute_size(type)), m_allocator(allocator) {
+        if (m_type.type == thing_type::Ref) return;
         // TODO: Account for alignment
         m_data = m_allocator.allocate(m_size);
         std::memset(m_data, 0, m_size);
@@ -51,19 +223,15 @@ public:
      * @brief Destructs a thing.
      */
     ~thing() {
-        if (m_data != nullptr && m_size > 0) m_allocator.deallocate(m_data, m_size);
+        if (m_type.type != thing_type::Ref && m_data != nullptr && m_size > 0) m_allocator.deallocate(m_data, m_size);
     }
 
     /**
      * @brief Move constructor.
      */
     thing(thing&& other) noexcept
-      : m_type(std::move(other.m_type)),
-        m_data(other.m_data),
-        m_size(other.m_size),
-        m_modules(std::move(other.m_modules)),
-        m_allocator(std::move(other.m_allocator)) {
-        other.m_type = {};
+      : m_type(other.m_type), m_data(other.m_data), m_size(other.m_size), m_allocator(std::move(other.m_allocator)) {
+        other.m_type.type = thing_type::Count;
         other.m_data      = nullptr;
         other.m_size      = 0;
     }
@@ -75,9 +243,8 @@ public:
         if (this == &other) return *this;
         m_type            = other.m_type;
         m_data            = other.m_data;
-        m_modules    = std::move(other.m_modules);
         m_allocator       = std::move(other.m_allocator);
-        other.m_type = {};
+        other.m_type.type = thing_type::Count;
         other.m_data      = nullptr;
         other.m_size      = 0;
         return *this;
@@ -85,8 +252,6 @@ public:
 
     thing(const thing&)            = delete;
     thing& operator=(const thing&) = delete;
-public:
-    void assign_mod_container(const mod_container& modules) { m_modules = modules; }
 public:
     /**
      * @brief Returns a clone of the thing.
@@ -94,18 +259,22 @@ public:
      * @return A clone of this thing.
      */
     thing clone() const {
-        thing res(resolve_type(m_type, m_modules), m_modules, m_allocator);
-        switch (m_type->t) {
-        case type_t::Primitive:
-        case type_t::Reference: {
-            std::memcpy(res.m_data, m_data, m_size);
-        } break;
-        case type_t::List: {
-            copy_list(resolve_type(*m_type->list, m_modules), res.get<list_t>(), get<list_t>());
-        } break;
-        case type_t::Import: throw std::runtime_error("unreachable");
+        thing res(m_type, m_allocator);
+        switch (m_type.type) {
+        case thing_type::S8:
+        case thing_type::S16:
+        case thing_type::S32:
+        case thing_type::S64:
+        case thing_type::U8:
+        case thing_type::U16:
+        case thing_type::U32:
+        case thing_type::U64:
+        case thing_type::Ptr: std::memcpy(res.m_data, m_data, m_size); return std::move(res);
+        case thing_type::Array: copy_list(m_type, res.get<array>(), get<array>()); return std::move(res);
+        case thing_type::Ref: throw std::runtime_error("cannot clone references");
+        case thing_type::Count: break;
         }
-        return std::move(res);
+        throw std::runtime_error("unreachable");
     }
 public:
     /**
@@ -113,14 +282,26 @@ public:
      *
      * @return The type.
      */
-    constexpr auto type() const { return *m_type; }
+    constexpr thing_type type() const { return m_type; }
 
     /**
-     * @brief Returns the thing's type.
+     * @brief Returns the thing's true type.
      *
-     * @return The shared pointer to the type.
+     * If the thing is a reference, returns the referenced type.
+     *
+     * @return The true type.
      */
-    auto type() { return m_type; }
+    constexpr thing_type true_type() const { return (m_type.type == thing_type::Ref) ? *m_type.value.typeRef : m_type; }
+
+    /**
+     * @brief Checks if the thing is of a specified type.
+     *
+     * Compares the true type.
+     *
+     * @param type Type to compare.
+     * @return true if the types match.
+     */
+    constexpr bool is(enum thing_type::type type) const { return true_type().type == type; }
 public:
     /**
      * @brief Returns a raw data pointer.
@@ -143,8 +324,7 @@ public:
      */
     template <typename T>
     T& get() {
-        std::size_t size = m_size > 0 ? m_size : compute_size_na(resolve_type(m_type, m_modules));
-        if (size != sizeof(T)) throw bad_thing_access();
+        if (compute_size_na(m_type) != sizeof(T)) throw bad_thing_access();
         return *std::launder(reinterpret_cast<T*>(m_data));
     }
 
@@ -155,8 +335,7 @@ public:
      */
     template <typename T>
     const T& get() const {
-        std::size_t size = m_size > 0 ? m_size : compute_size_na(resolve_type(m_type, m_modules));
-        if (size != sizeof(T)) throw bad_thing_access();
+        if (compute_size_na(m_type) != sizeof(T)) throw bad_thing_access();
         return *std::launder(reinterpret_cast<const T*>(m_data));
     }
 public:
@@ -253,129 +432,311 @@ public:
      *
      * @return The integer value.
      */
-    long_t integer() const {
-        if (m_type->t != type_t::Primitive) throw bad_thing_access();
-        switch (m_type->primitive) {
-        case sizeof(byte_t): return get<byte_t>();
-        case sizeof(short_t): return get<short_t>();
-        case sizeof(int_t): return get<int_t>();
-        case sizeof(long_t): return get<long_t>();
+    thing_type::s64 integer() const {
+        switch (true_type().type) {
+        case thing_type::S8: return get<thing_type::s8>();
+        case thing_type::S16: return get<thing_type::s16>();
+        case thing_type::S32: return get<thing_type::s32>();
+        case thing_type::S64: return get<thing_type::s64>();
+        case thing_type::U8: return get<thing_type::u8>();
+        case thing_type::U16: return get<thing_type::u16>();
+        case thing_type::U32: return get<thing_type::u32>();
+        case thing_type::U64: return get<thing_type::u64>();
         default: throw std::runtime_error("unreachable");
         }
     }
 
-    thing reference() const {
-        thing res              = { std::make_shared<class type>(m_type), m_modules, m_allocator };
-        res.get<reference_t>() = m_data;
-        return std::move(res);
-    }
+    void resize(thing_type::u64 newSize) {
+        if (!is(thing_type::Array)) throw bad_thing_access();
+        if (true_type().value.array.size > 0) throw std::runtime_error("cannot resize a static array");
 
-    thing resolve() const {
-        thing rsv = { resolve_type(m_type, m_modules), m_data, m_allocator };
-        while (rsv.type()->t == type_t::Reference)
-            rsv = { rsv.m_type->reference, rsv.get<reference_t>(), std::move(rsv.m_allocator) };
-        return rsv;
-    }
-
-    void resize(long_t newSize) {
-        if (m_type->t != type_t::List) throw bad_thing_access();
-        auto& list = get<list_t>();
-        if (newSize < 0 || newSize == list.size) return;
-        std::byte* newData = new std::byte[compute_size_na(resolve_type(*m_type->list, m_modules)) * newSize];
+        auto& array = get<union array>();
+        if (newSize < 0 || newSize == array.dynamic.size) return;
+        std::size_t innerSize = compute_size_na(*true_type().value.array.type);
+        std::byte*  newData   = new std::byte[innerSize * newSize];
         std::memcpy(newData,
-            list.data,
-            compute_size_na(resolve_type(*m_type->list, m_modules)) * std::min(list.size, newSize));
-        list.size = newSize;
-        delete[] list.data;
-        list.data = newData;
+            array.dynamic.data,
+            innerSize * std::min(static_cast<thing_type::u64>(array.dynamic.size), newSize));
+        array.dynamic.size = newSize;
+        delete[] array.dynamic.data;
+        array.dynamic.data = newData;
     }
 
-    thing at(long_t index) const {
-        if (m_type->t != type_t::List) throw bad_thing_access();
-        auto& list = get<list_t>();
-        if (index < 0 || index >= list.size) throw std::out_of_range("index out of range");
-        thing res              = { *m_type->list, m_modules, m_allocator };
-        res.get<reference_t>() = list.data; // TODO: Account for padding, alignment and stuff
-        return std::move(res);
+    thing at(thing_type::u64 index) const {
+        if (!is(thing_type::Array)) throw bad_thing_access();
+
+        std::size_t elementSize = compute_size_na(*m_type.value.array.type);
+        if (m_type.value.array.size == 0) {
+            auto& array = get<union array>();
+            if (index < 0 || index >= array.dynamic.size) throw std::out_of_range("index out of range");
+            thing ref  = { { thing_type::Ref, m_type.value.array.type }, m_allocator };
+            ref.m_data = array.dynamic.data + (index * elementSize);
+            return ref;
         }
-public:
-    static type_p resolve_type(const type_p& initType, const mod_container& modules) {
-        type_p rsv = initType;
-        while (rsv->t == type_t::Import)
-            rsv = *modules->at(initType->imp.mod)->type_at(initType->imp.type);
-        return rsv;
+
+        std::byte* data = reinterpret_cast<array*>(m_data)->flat;
+        if (index < 0 || index >= m_type.value.array.size) throw std::out_of_range("index out of range");
+        thing ref  = { { thing_type::Ref, m_type.value.array.type }, m_allocator };
+        ref.m_data = data + (index * elementSize);
+        return ref;
+    }
+
+    thing_type::u64 length() const {
+        if (!is(thing_type::Array)) throw bad_thing_access();
+        return true_type().value.array.size == 0 ? get<array>().dynamic.size : true_type().value.array.size;
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>>
+    T cast_to() const {
+        return visit_primitive([](auto value) { return static_cast<T>(value); });
+    }
+
+    /**
+     * @brief Changes reference thing's referenced thing.
+     *
+     * Yes.
+     *
+     * @param thing Thing.
+     */
+    void reference(const thing& thing) {
+        if (m_type.type != thing_type::Ref || *m_type.value.typeRef != thing.type()) throw bad_thing_access();
+        m_data = thing.m_data;
+    }
+
+    /**
+     * @brief Self-explainatory.
+     *
+     * TODO: Document
+     */
+    void assign(thing&& thing) {
+        class thing rhs = std::move(thing);
+        if (true_type() != rhs.true_type()) throw std::runtime_error("thing type mismatch");
+        // TODO: Move this to another function
+        switch (true_type().type) {
+        case thing_type::S8:
+        case thing_type::S16:
+        case thing_type::S32:
+        case thing_type::S64:
+        case thing_type::U8:
+        case thing_type::U16:
+        case thing_type::U32:
+        case thing_type::U64: std::memcpy(m_data, rhs.m_data, m_size); return;
+        case thing_type::Ptr:
+        case thing_type::Ref:
+        case thing_type::Array: throw std::runtime_error("unimplemented");
+        case thing_type::Count: break;
+        }
+        throw std::runtime_error("unreachable");
     }
 private:
-    static void copy_list(const type_p& innerType, list_t& dst, const list_t& src) {
-        dst.size = src.size;
-        if (dst.size <= 0) {
-            dst.data = nullptr;
+    static void copy_list(const thing_type& arrayType, array& dst, const array& src) {
+        if (arrayType.type != thing_type::Array || arrayType.value.array.type == nullptr)
+            throw std::runtime_error("invalid type");
+
+        const auto& innerType   = *arrayType.value.array.type;
+        std::size_t elementSize = compute_size_na(innerType);
+
+        std::byte*       data    = nullptr;
+        const std::byte* srcData = nullptr;
+        std::size_t      size    = 0;
+        if (arrayType.value.array.size == 0) {
+            size = dst.dynamic.size = src.dynamic.size;
+            if (dst.dynamic.size < 0) {
+                dst.dynamic.data = nullptr;
                 return;
             }
-        if (innerType == nullptr) throw std::runtime_error("inner type should not be null!");
 
-        std::size_t size = compute_size_na(innerType) * dst.size;
-        dst.data         = new std::byte[size];
-        switch (innerType->t) {
-        case type_t::Primitive:
-        case type_t::Reference: std::memcpy(dst.data, src.data, size); break;
-        case type_t::List:
+            srcData = src.dynamic.data;
+            data = dst.dynamic.data = new std::byte[dst.dynamic.size];
+        } else {
+            data    = dst.flat;
+            srcData = src.flat;
+            size    = arrayType.value.array.size;
+        }
+
+        switch (innerType.type) {
+        case thing_type::S8:
+        case thing_type::S16:
+        case thing_type::S32:
+        case thing_type::S64:
+        case thing_type::U8:
+        case thing_type::U16:
+        case thing_type::U32:
+        case thing_type::U64:
+        case thing_type::Ptr:
+        case thing_type::Ref: std::memcpy(dst.flat, src.flat, size); return;
+        case thing_type::Array:
             for (std::size_t i = 0; i < size; ++i) {
-                copy_list(*innerType->list,
-                    *std::launder(reinterpret_cast<list_t*>(dst.data)),
-                    *std::launder(reinterpret_cast<list_t*>(src.data)));
+                copy_list(*innerType.value.array.type,
+                    *std::launder(reinterpret_cast<array*>(data + (i * elementSize))),
+                    *std::launder(reinterpret_cast<const array*>(srcData + (i * elementSize))));
             }
-            break;
-        case type_t::Import: throw std::runtime_error("unresolved type");
+            return;
+        case thing_type::Count: break;
         }
+        throw std::runtime_error("unreachable");
     }
 private:
-    static std::size_t compute_size_na(const type_p& type) {
-        switch (type->t) {
-        case type_t::Primitive: return type->primitive;
-        case type_t::Reference: return sizeof(reference_t);
-        case type_t::List: return sizeof(list_t);
-        case type_t::Import: throw std::runtime_error("unresolved type");
+    static std::size_t compute_size_na(const thing_type& type) {
+        switch (type.type) {
+        case thing_type::S8: return sizeof(thing_type::s8);
+        case thing_type::S16: return sizeof(thing_type::s16);
+        case thing_type::S32: return sizeof(thing_type::s32);
+        case thing_type::S64: return sizeof(thing_type::s64);
+        case thing_type::U8: return sizeof(thing_type::u8);
+        case thing_type::U16: return sizeof(thing_type::u16);
+        case thing_type::U32: return sizeof(thing_type::u32);
+        case thing_type::U64: return sizeof(thing_type::u64);
+        case thing_type::Ptr: return sizeof(void*);
+        case thing_type::Ref: return compute_size_na(*type.value.typeRef);
+        case thing_type::Array:
+            return type.value.array.size == 0 ? sizeof(array)
+                                              : compute_size_na(*type.value.array.type) * type.value.array.size;
+        case thing_type::Count: break;
         }
 
         throw std::runtime_error("unreachable");
     }
 
     // NOTE: Align to 4 bytes
-    static std::size_t compute_size(const type_p& type) { return (compute_size_na(type) + 3) & ~3; }
-private:
-    thing(const type_p& type, std::byte* data, const allocator_type& allocator = {})
-      : m_type(type), m_size(0), m_data(data), m_allocator(allocator) {}
+    static std::size_t compute_size(const thing_type& type) { return (compute_size_na(type) + 3) & ~3; }
 private:
+    template <typename Func>
+    decltype(auto) visit_primitive(Func&& func) const {
+        switch (true_type().type) {
+        case thing_type::S8: return std::forward<Func>(func)(get<thing_type::s8>());
+        case thing_type::S16: return std::forward<Func>(func)(get<thing_type::s16>());
+        case thing_type::S32: return std::forward<Func>(func)(get<thing_type::s32>());
+        case thing_type::S64: return std::forward<Func>(func)(get<thing_type::s64>());
+        case thing_type::U8: return std::forward<Func>(func)(get<thing_type::u8>());
+        case thing_type::U16: return std::forward<Func>(func)(get<thing_type::u16>());
+        case thing_type::U32: return std::forward<Func>(func)(get<thing_type::u32>());
+        case thing_type::U64: return std::forward<Func>(func)(get<thing_type::u64>());
+        default: throw bad_thing_access();
+        }
+    }
+
     template <typename Op>
     thing binary_op(const thing& rhs, const Op& op) const {
-        const thing lhsRsv = resolve();
-        const thing rhsRsv = rhs.resolve();
+        if (thing_type::is_primitive(true_type().type) && thing_type::is_primitive(true_type().type)) {
+            static constexpr enum thing_type::type promotions[8 * 8] = {
+                // S8
+                thing_type::S8,
+                thing_type::S16,
+                thing_type::S32,
+                thing_type::S64,
+                thing_type::S16,
+                thing_type::S16,
+                thing_type::S32,
+                thing_type::U64,
+                // S16
+                thing_type::S16,
+                thing_type::S16,
+                thing_type::S32,
+                thing_type::S64,
+                thing_type::S16,
+                thing_type::S16,
+                thing_type::S32,
+                thing_type::U64,
+                // S32
+                thing_type::S32,
+                thing_type::S32,
+                thing_type::S32,
+                thing_type::S64,
+                thing_type::S32,
+                thing_type::S32,
+                thing_type::U32,
+                thing_type::U64,
+                // S64
+                thing_type::S64,
+                thing_type::S64,
+                thing_type::S64,
+                thing_type::S64,
+                thing_type::S64,
+                thing_type::S64,
+                thing_type::S64,
+                thing_type::U64,
+                // U8
+                thing_type::S16,
+                thing_type::S16,
+                thing_type::S32,
+                thing_type::S64,
+                thing_type::U8,
+                thing_type::U16,
+                thing_type::U32,
+                thing_type::U64,
+                // U16
+                thing_type::S16,
+                thing_type::S16,
+                thing_type::S32,
+                thing_type::S64,
+                thing_type::U16,
+                thing_type::U16,
+                thing_type::U32,
+                thing_type::U64,
+                // U32
+                thing_type::S32,
+                thing_type::S32,
+                thing_type::U32,
+                thing_type::S64,
+                thing_type::U32,
+                thing_type::U32,
+                thing_type::U32,
+                thing_type::U64,
+                // U64
+                thing_type::U64,
+                thing_type::U64,
+                thing_type::U64,
+                thing_type::U64,
+                thing_type::U64,
+                thing_type::U64,
+                thing_type::U64,
+                thing_type::U64,
+            };
 
-        if (lhsRsv.type().t == type_t::Primitive && rhsRsv.type().t == type_t::Primitive) {
-            std::size_t size = std::max(lhsRsv.type().primitive, rhsRsv.type().primitive);
+            enum thing_type::type resultType = promotions[true_type().type + (rhs.true_type().type * 8)];
 
-            long_t result = op(lhsRsv.integer(), rhsRsv.integer());
-
-            thing res({ size }, m_modules, m_allocator);
-            switch (size) {
-            case sizeof(byte_t): res.get<byte_t>() = result; break;
-            case sizeof(short_t): res.get<short_t>() = result; break;
-            case sizeof(int_t): res.get<int_t>() = result; break;
-            case sizeof(long_t): res.get<long_t>() = result; break;
-            default: throw std::runtime_error("unreachable");
+            thing res = { thing_type{ resultType }, m_allocator };
+            switch (resultType) {
+            case thing_type::S8:
+                res.get<thing_type::s8>() = Op{}(cast_to<thing_type::s8>(), rhs.cast_to<thing_type::s8>());
+                return res;
+            case thing_type::S16:
+                res.get<thing_type::s16>() = Op{}(cast_to<thing_type::s16>(), rhs.cast_to<thing_type::s16>());
+                return res;
+            case thing_type::S32:
+                res.get<thing_type::s32>() = Op{}(cast_to<thing_type::s32>(), rhs.cast_to<thing_type::s32>());
+                return res;
+            case thing_type::S64:
+                res.get<thing_type::s64>() = Op{}(cast_to<thing_type::s64>(), rhs.cast_to<thing_type::s64>());
+                return res;
+            case thing_type::U8:
+                res.get<thing_type::u8>() = Op{}(cast_to<thing_type::u8>(), rhs.cast_to<thing_type::u8>());
+                return res;
+            case thing_type::U16:
+                res.get<thing_type::u16>() = Op{}(cast_to<thing_type::u16>(), rhs.cast_to<thing_type::u16>());
+                return res;
+            case thing_type::U32:
+                res.get<thing_type::u32>() = Op{}(cast_to<thing_type::u32>(), rhs.cast_to<thing_type::u32>());
+                return res;
+            case thing_type::U64:
+                res.get<thing_type::u64>() = Op{}(cast_to<thing_type::u64>(), rhs.cast_to<thing_type::u64>());
+                return res;
+            case thing_type::Ptr: // TODO: Pointer arithmetics
+            case thing_type::Ref:
+            case thing_type::Array:
+            case thing_type::Count: break;
             }
-            return std::move(res);
+            throw std::runtime_error("unreachable");
         }
 
         throw std::runtime_error("unexpected operation");
     }
 private:
-    type_p      m_type;
+    thing_type  m_type;
     std::size_t m_size;
     std::byte*  m_data;
 
-    mod_container  m_modules;
     allocator_type m_allocator;
 };
 

furvm/include/furvm/thing_allocator.hpp

@@ -69,8 +69,9 @@ public:
     [[nodiscard]] T* allocate(std::size_t count = 1) {
         for (auto it = m_deadThings->begin(); it != m_deadThings->end(); ++it) {
             if (it->second != count) continue;
+            T* data = it->first;
             m_deadThings->erase(it);
-            return it->first;
+            return data;
         }
         return m_arena->allocate<T>(count);
     }

furvm/include/furvm/type.hpp

@@ -1,141 +0,0 @@
-#ifndef FURVM_TYPE_HPP
-#define FURVM_TYPE_HPP
-
-#include "furvm/fwd.hpp"
-#include "furvm/handle.hpp" // IWYU pragma: keep
-
-#include <cstdint>
-namespace furvm {
-
-enum class type_t : std::uint32_t {
-    Primitive = 0,
-    Reference,
-    List,
-
-    Import,
-};
-
-using primitive_type = std::uint64_t;
-using reference_type = type_p;
-using list_type      = type_h;
-
-struct import_type {
-    mod_id  mod;
-    type_id type;
-};
-
-struct type {
-    type_t t;
-    union {
-        primitive_type primitive;
-        reference_type reference;
-        list_type      list;
-        import_type    imp;
-    };
-
-    type(type_t type)
-      : t(type), primitive(0) {}
-
-    type(primitive_type primitive)
-      : t(type_t::Primitive), primitive(primitive) {}
-
-    type(const reference_type& reference)
-      : t(type_t::Reference), reference(reference) {}
-
-    type(const list_type& list)
-      : t(type_t::List), list(list) {}
-
-    type(const import_type& imp)
-      : t(type_t::Import), imp(imp) {}
-
-    ~type() {
-        switch (t) {
-        case type_t::Reference: reference.~reference_type(); break;
-        case type_t::List: list.~list_type(); break;
-        case type_t::Import: imp.~import_type(); break;
-        default: break;
-        }
-    }
-
-    type(type&& other) noexcept
-      : t(other.t) {
-        switch (t) {
-        case type_t::Primitive: primitive = other.primitive; break;
-        case type_t::Reference: reference = std::move(other.reference); break;
-        case type_t::List: list = std::move(other.list); break;
-        case type_t::Import: imp = std::move(other.imp); break;
-        }
-    }
-
-    type& operator=(type&& other) noexcept {
-        if (this == &other) return *this;
-        t = other.t;
-        switch (t) {
-        case type_t::Primitive: primitive = other.primitive; break;
-        case type_t::Reference: reference = std::move(other.reference); break;
-        case type_t::List: list = std::move(other.list); break;
-        case type_t::Import: imp = std::move(other.imp); break;
-        }
-
-        return *this;
-    }
-
-    type(const type& other)
-      : t(other.t) {
-        switch (t) {
-        case type_t::Primitive: primitive = other.primitive; break;
-        case type_t::Reference: reference = other.reference; break;
-        case type_t::List: list = other.list; break;
-        case type_t::Import: imp = other.imp; break;
-        }
-    }
-
-    type& operator=(const type& other) {
-        if (this == &other) return *this;
-        t = other.t;
-        switch (t) {
-        case type_t::Primitive: primitive = other.primitive; break;
-        case type_t::Reference: reference = other.reference; break;
-        case type_t::List: list = other.list; break;
-        case type_t::Import: imp = other.imp; break;
-        }
-
-        return *this;
-    }
-};
-
-using byte_t  = std::int8_t;  /**< A 1-byte integer. */
-using short_t = std::int16_t; /**< A 2-byte integer. */
-using int_t   = std::int32_t; /**< A 4-byte integer. */
-using long_t  = std::int64_t; /**< An 8-byte integer. */
-
-using reference_t = std::byte*;
-
-struct list_t {
-    long_t     size;
-    std::byte* data;
-};
-
-/**
- * @brief A 1-byte integer thing type.
- */
-inline static type byteType = { sizeof(byte_t) }; // NOLINT
-
-/**
- * @brief A 2-byte integer thing type.
- */
-inline static type shortType = { sizeof(short_t) }; // NOLINT
-
-/**
- * @brief A 4-byte integer thing type.
- */
-inline static type intType = { sizeof(int_t) }; // NOLINT
-
-/**
- * @brief An 8-byte integer thing type.
- */
-inline static type longType = { sizeof(long_t) }; // NOLINT
-
-} // namespace furvm
-
-#endif // FURVM_TYPE_HPP

furvm/src/context.cpp

@@ -1,24 +0,0 @@
-#include "furvm/context.hpp"
-
-#include "furvm/thing.hpp" // IWYU pragma: keep
-#include "furvm/type.hpp"
-
-#include <cstdint>
-#include <memory>
-
-namespace furvm {
-
-context::context()
-  : m_thingAllocator(m_thingArena) {
-    mod core;
-    core.emplace_type(std::make_shared<type>(byteType));
-    core.emplace_type(std::make_shared<type>(shortType));
-    core.emplace_type(std::make_shared<type>(intType));
-    core.emplace_type(std::make_shared<type>(longType));
-    static_assert(sizeof(std::uintptr_t) == 8, "Unsupported platform");
-    core.emplace_type(*core.type_at(3));
-
-    emplace("core", std::move(core)).dispatch();
-}
-
-} // namespace furvm

furvm/src/executor.cpp

@@ -7,12 +7,43 @@
 #include "furvm/instruction.hpp"
 #include "furvm/thing.hpp"
 
+#include <cassert>
 #include <cstdint>
 #include <stdexcept>
+#include <utility>
 #include <vector>
 
 namespace furvm {
 
+thing_type executor::thing_type_impl(mod_h mod, mod_type type) const {
+    while (type.type == mod_type::Import) {
+        auto imprt = std::move(type.value.imprt);
+        mod        = m_context->at(imprt.modId);
+        type       = *mod->type_at(imprt.typeId);
+    }
+    switch (static_cast<enum thing_type::type>(type.type)) {
+    case thing_type::S8:
+    case thing_type::S16:
+    case thing_type::S32:
+    case thing_type::S64:
+    case thing_type::U8:
+    case thing_type::U16:
+    case thing_type::U32:
+    case thing_type::U64: return { static_cast<enum thing_type::type>(type.type) };
+    case thing_type::Ptr: return { thing_type::Ptr, thing_type(mod, *mod->type_at(type.value.typeRef)) };
+    case thing_type::Array: {
+        return { static_cast<enum thing_type::type>(type.type),
+            { thing_type(mod, *mod->type_at(type.value.array.typeId)), type.value.array.size } };
+    }
+    default: throw std::runtime_error("invalid thing type");
+    }
+}
+
+thing_type* executor::thing_type(const mod_h& mod, const mod_type& type) const {
+    struct thing_type thingType = thing_type_impl(mod, type);
+    return m_context->thing_type_store().insert(thingType);
+}
+
 void executor::push_frame(const mod_h& mod, function function) {
     mod_h modInst = mod;
     while (function.type() == function_t::Import) {
@@ -20,19 +51,28 @@ void executor::push_frame(const mod_h& mod, function function) {
         function = *modInst->function_at(function.imp().function);
     }
 
+    auto                 signature = function.signature();
     std::vector<thing_h> args;
-    args.reserve(function.param_count());
-    for (size_t i = 0; i < function.param_count(); ++i)
-        args.push_back(pop_thing());
+    args.reserve(signature.params.size());
+    for (const auto& param : signature.params) {
+        auto arg = pop_thing();
+        if (arg->type() != *thing_type(mod, *param)) throw std::runtime_error("function argument type mismatch");
+        args.push_back(std::move(arg));
+    }
+
+    struct thing_type* returnType = nullptr;
+    if (function.signature().returnType.has_value())
+        returnType = thing_type(mod, *function.signature().returnType.value()); // NOLINT
 
     switch (function.type()) {
     case function_t::Normal: {
-        m_frames.emplace((struct executor::frame){ mod, function.position(), m_stack.size(), std::move(args) });
+        m_frames.emplace(
+            (struct executor::frame){ mod, function.position(), m_stack.size(), returnType, std::move(args) });
     } break;
     case function_t::Native: {
-        m_frames.emplace((struct executor::frame){ mod, 0, m_stack.size(), std::move(args) });
+        m_frames.emplace((struct executor::frame){ mod, 0, m_stack.size(), returnType, std::move(args) });
         modInst->get_native_function(function.native())(*this);
-        m_frames.pop();
+        pop_frame();
     } break;
     default: throw std::runtime_error("unexpected function type");
     }
@@ -42,6 +82,10 @@ struct executor::frame executor::pop_frame() {
     if (m_frames.empty()) throw stack_underflow();
     struct executor::frame frame = m_frames.top();
     m_frames.pop();
+    thing_h returnValue;
+    if (frame.returnType != nullptr) returnValue = pop_thing();
+    if (m_stack.size() != frame.stackBase) throw std::runtime_error("unexhausted stack");
+    if (frame.returnType != nullptr) push_thing(std::move(returnValue));
     return frame;
 }
 
@@ -57,7 +101,7 @@ thing_h executor::pop_thing() {
     if (m_frames.top().stackBase >= m_stack.size()) throw stack_underflow();
     thing_h top = std::move(m_stack.top());
     m_stack.pop();
-    return top;
+    return std::move(top);
 }
 
 thing_h executor::thing() const {
@@ -79,7 +123,7 @@ void executor::store_thing(variable_t variable, thing_h&& thing) {
 
 thing_h executor::load_thing(variable_t variable) const {
     const auto& frame = m_frames.top();
-    return frame.variables[variable];
+    return { frame.variables[variable] };
 }
 
 void executor::step() {
@@ -90,9 +134,63 @@ void executor::step() {
     instruction_t instr = static_cast<instruction_t>((*frame.mod).byte(frame.position++));
     switch (instr) {
     case instruction_t::NoOperation: break;
-    case instruction_t::PushB2I: {
-        push_thing({ *m_context->at("core")->type_at(2), m_context, m_context->thing_alloc() })->get<int_t>() =
-            frame.mod->byte(frame.position++);
+    case instruction_t::PushS8: {
+        push_thing({ (struct thing_type){ thing_type::S8 }, m_context->thing_alloc() })->get<thing_type::s8>() =
+            static_cast<thing_type::s8>(frame.mod->byte(frame.position++));
+    } break;
+    case instruction_t::PushU8: {
+        push_thing({ (struct thing_type){ thing_type::U8 }, m_context->thing_alloc() })->get<thing_type::u8>() =
+            static_cast<thing_type::u8>(frame.mod->byte(frame.position++));
+    } break;
+    case instruction_t::PushS16: {
+        thing_type::u16 value = frame.mod->byte(frame.position++);
+        value                |= static_cast<thing_type::u16>(frame.mod->byte(frame.position++) << 8);
+        push_thing({ (struct thing_type){ thing_type::S16 }, m_context->thing_alloc() })->get<thing_type::s16>() =
+            static_cast<thing_type::s16>(value);
+    } break;
+    case instruction_t::PushU16: {
+        thing_type::u16 value = frame.mod->byte(frame.position++);
+        value                |= static_cast<thing_type::u16>(frame.mod->byte(frame.position++) << 8);
+        push_thing({ (struct thing_type){ thing_type::U16 }, m_context->thing_alloc() })->get<thing_type::u16>() =
+            value;
+    } break;
+    case instruction_t::PushS32: {
+        push_thing({ (struct thing_type){ thing_type::S32 }, m_context->thing_alloc() })->get<thing_type::s32>() =
+            static_cast<thing_type::s32>(frame.mod->byte(frame.position++));
+    } break;
+    case instruction_t::PushU32: {
+        push_thing({ (struct thing_type){ thing_type::U32 }, m_context->thing_alloc() })->get<thing_type::u32>() =
+            static_cast<thing_type::u32>(frame.mod->byte(frame.position++));
+    } break;
+    case instruction_t::Array: {
+        mod_type_id typeId = static_cast<mod_type_id>(frame.mod->byte(frame.position)) |
+                             (static_cast<mod_type_id>(frame.mod->byte(frame.position + 1)) << 8) |
+                             (static_cast<mod_type_id>(frame.mod->byte(frame.position + 2)) << 16) |
+                             (static_cast<mod_type_id>(frame.mod->byte(frame.position + 3)) << 24);
+        frame.position    += 4;
+
+        const auto& type = *thing_type(frame.mod, *frame.mod->type_at(typeId));
+        if (type.type != thing_type::Array || type.value.array.type == nullptr || type.value.array.type == &type)
+            throw std::runtime_error("invalid array type");
+
+        auto array = push_thing({ type, m_context->thing_alloc() });
+
+        if (type.value.array.size == 0) {
+            auto         sizeThing = pop_thing();
+            std::int64_t size      = sizeThing->integer();
+            array->resize(size);
+        }
+    } break;
+    case instruction_t::Get: {
+        auto index = pop_thing();
+        auto array = pop_thing();
+        push_thing(array->at(index->integer()));
+    } break;
+    case instruction_t::Set: {
+        auto element = pop_thing();
+        auto index   = pop_thing();
+        auto array   = pop_thing();
+        array->at(index->integer()).assign(std::move(element->clone()));
     } break;
     case instruction_t::Drop: {
         pop_thing();
@@ -100,12 +198,20 @@ void executor::step() {
     case instruction_t::Duplicate: {
         push_thing(thing());
     } break;
+    case instruction_t::Swap: {
+        auto thing1 = pop_thing();
+        auto thing2 = pop_thing();
+        push_thing(std::move(thing1));
+        push_thing(std::move(thing2));
+    } break;
     case instruction_t::Clone: {
         push_thing(std::move(thing()->clone()));
     } break;
     case instruction_t::Reference: {
         auto thing = pop_thing();
-        push_thing(std::move(thing->reference()));
+        push_thing({ (struct thing_type){ thing_type::Ref, m_context->thing_type_store().insert(thing->type()) },
+                       m_context->thing_alloc() })
+            ->reference(*thing);
     } break;
     case instruction_t::Add: {
         auto rhs = pop_thing();
@@ -163,29 +269,40 @@ void executor::step() {
         push_thing(lhs->greater_equals(*rhs));
     } break;
     case instruction_t::Pointerof: {
-        auto thing = pop_thing()->resolve();
-        auto ptr   = push_thing({ *m_context->at("core")->type_at(4), m_context, m_context->thing_alloc() });
-        switch (furvm::thing<>::resolve_type(thing.type(), m_context)->t) {
-        case type_t::Primitive: ptr->get<std::uintptr_t>() = reinterpret_cast<std::uintptr_t>(thing.raw()); break;
-        case type_t::List:
-            ptr->get<std::uintptr_t>() = reinterpret_cast<std::uintptr_t>(thing.get<list_t>().data);
+        auto thing = pop_thing();
+        auto ptr =
+            push_thing({ (struct thing_type){ thing_type::Ptr, m_context->thing_type_store().at(thing->type().id) },
+                m_context->thing_alloc() });
+        ptr->get<void*>() = thing->raw();
+    } break;
+    case instruction_t::Sizeof: {
+        auto thing = pop_thing();
+        auto size  = push_thing({ (struct thing_type){ thing_type::U64 }, m_context->thing_alloc() });
+        switch (thing->type().type) {
+        case thing_type::S8:
+        case thing_type::S16:
+        case thing_type::S32:
+        case thing_type::S64:
+        case thing_type::U8:
+        case thing_type::U16:
+        case thing_type::U32:
+        case thing_type::U64:
+            size->get<thing_type::u64>() = static_cast<thing_type::u64>(thing_type::primitive_size(thing->type().type));
+            break;
+        case thing_type::Ptr: size->get<thing_type::u64>() = static_cast<thing_type::u64>(sizeof(void*)); break;
+        case thing_type::Array:
+            /* TODO: Return actual memory size of the array
+             * By the memory size I mean the length times sizeof single element.
+             */
+            size->get<thing_type::u64>() = thing->length();
             break;
-        case type_t::Reference:
-        case type_t::Import:
         default: throw std::runtime_error("unreachable");
         }
     } break;
-    case instruction_t::Sizeof: {
-        auto thing = pop_thing()->resolve();
-        auto ptr   = push_thing({ *m_context->at("core")->type_at(3), m_context, m_context->thing_alloc() });
-        auto type  = furvm::thing<>::resolve_type(thing.type(), m_context);
-        switch (type->t) {
-        case type_t::Primitive: ptr->get<long_t>() = static_cast<long_t>(type->primitive); break;
-        case type_t::List: ptr->get<long_t>() = thing.get<list_t>().size; break;
-        case type_t::Reference:
-        case type_t::Import:
-        default: throw std::runtime_error("unreachable");
-        }
+    case instruction_t::Lengthof: {
+        auto thing  = pop_thing();
+        auto length = push_thing({ (struct thing_type){ thing_type::U64 }, m_context->thing_alloc() });
+        length->get<thing_type::u64>() = thing->length();
     } break;
     case instruction_t::Load: {
         variable_t variable = static_cast<std::uint16_t>(frame.mod->byte(frame.position)) |
@@ -206,22 +323,18 @@ void executor::step() {
         push_frame(frame.mod, *frame.mod->function_at(funcId));
     } break;
     case instruction_t::Jump: {
-        frame.position += ((std::int8_t)frame.mod->byte(frame.position)) + 1;
+        std::int8_t offset = static_cast<std::int8_t>(frame.mod->byte(frame.position++));
+        frame.position    += offset;
     } break;
     case instruction_t::JumpNotZero: {
         byte offset = frame.mod->byte(frame.position++);
         auto cond   = pop_thing();
-        if (cond->get<int_t>() != 0) frame.position += (std::int8_t)offset;
+        if (cond->integer() != 0) frame.position += (std::int8_t)offset;
     } break;
     case instruction_t::Return: {
         pop_frame();
         if (m_frames.empty()) m_flags = m_flags | executor_flags::Done;
     } break;
-    case instruction_t::ReturnValue: {
-        auto value = pop_thing();
-        pop_frame();
-        push_thing(std::move(value));
-    } break;
     case instruction_t::PushConstant: throw std::runtime_error("unimplemented");
     default: throw std::runtime_error("unknown instruction");
     }

furvm/src/function.cpp

@@ -7,7 +7,7 @@
 namespace furvm {
 
 function::function(const mod_h& mod, const function_h& function)
-  : m_type(function_t::Import), m_paramCount(0), m_value(import_function{ mod.id(), function.id() }) {}
+  : m_type(function_t::Import), m_value(import_function{ mod.id(), function.id() }) {}
 
 function::~function() {
     switch (m_type) {
@@ -23,7 +23,7 @@ function::~function() {
 }
 
 function::function(function&& other) noexcept
-  : m_name(std::move(other.m_name)), m_type(other.m_type), m_paramCount(other.m_paramCount) {
+  : m_type(other.m_type), m_signature(std::move(other.m_signature)) {
     switch (m_type) {
     case function_t::Normal: {
         m_value.position = other.m_value.position;
@@ -42,9 +42,8 @@ function::function(function&& other) noexcept
 function& function::operator=(function&& other) noexcept {
     if (this == &other) return *this;
 
-    m_name       = std::move(other.m_name);
     m_type      = other.m_type;
-    m_paramCount = other.m_paramCount;
+    m_signature = other.m_signature;
     switch (m_type) {
     case function_t::Normal: {
         m_value.position = other.m_value.position;
@@ -63,7 +62,7 @@ function& function::operator=(function&& other) noexcept {
 }
 
 function::function(const function& other)
-  : m_name(other.m_name), m_type(other.m_type), m_paramCount(other.m_paramCount) {
+  : m_type(other.m_type), m_signature(other.m_signature) {
     switch (m_type) {
     case function_t::Normal: {
         m_value.position = other.m_value.position;
@@ -81,9 +80,8 @@ function::function(const function& other)
 function& function::operator=(const function& other) {
     if (this == &other) return *this;
 
-    m_name       = other.m_name;
     m_type      = other.m_type;
-    m_paramCount = other.m_paramCount;
+    m_signature = other.m_signature;
     switch (m_type) {
     case function_t::Normal: {
         m_value.position = other.m_value.position;
@@ -100,4 +98,12 @@ function& function::operator=(const function& other) {
     return *this;
 }
 
+namespace detail {
+
+std::size_t function_sig_hash::operator()(const function_sig& signature) const {
+    return furlang::utility::vector_hash<mod_type_h, detail::handle_hash<mod_type_h>>{}(signature.params);
+}
+
+} // namespace detail
+
 } // namespace furvm

furvm/src/main.cpp

@@ -10,28 +10,78 @@
 #include <memory>
 #include <sstream>
 
+static void print_thing(const furvm::thing<furvm::thing_allocator>& thing) {
+    using namespace furvm;
+
+    switch (thing.true_type().type) {
+    case thing_type::S8: std::cout << thing.cast_to<thing_type::s16>(); break;
+    case thing_type::S16: std::cout << thing.get<thing_type::s16>(); break;
+    case thing_type::S32: std::cout << thing.get<thing_type::s32>(); break;
+    case thing_type::S64: std::cout << thing.get<thing_type::s64>(); break;
+    case thing_type::U8: std::cout << thing.get<thing_type::u8>(); break;
+    case thing_type::U16: std::cout << thing.get<thing_type::u16>(); break;
+    case thing_type::U32: std::cout << thing.get<thing_type::u32>(); break;
+    case thing_type::U64: std::cout << thing.get<thing_type::u64>(); break;
+    case thing_type::Array:
+        std::cout << "{ ";
+        for (thing_type::u64 i = 0; i < thing.length(); ++i) {
+            if (i > 0) std::cout << ", ";
+            print_thing(thing.at(i));
+        }
+        std::cout << " }";
+        break;
+    default: std::cerr << "{Type not recognized}";
+    }
+}
+
 int main(int argc, char** argv) {
+    auto context = std::make_shared<furvm::context>();
+
+#if 1 // NOLINT
     if (argc != 2) {
         std::cerr << "Usage: " << argv[0] << " <mod.fmod>\n";
         return 1;
     }
 
-    auto context = std::make_shared<furvm::context>();
-
     std::ifstream file(argv[1]);
     if (!file.is_open()) {
         std::cerr << "Failed to open " << argv[1] << '\n';
         return 1;
     }
 
-    furvm::mod_h      mod  = context->emplace("main", furvm::mod::load(file));
-    furvm::function_h func = mod->function_at("main");
+    furvm::mod_h mod      = context->emplace("main", std::move(furvm::mod::load(file)));
+    auto         mainFunc = mod->function_at("main", furvm::function_sig{});
+#else
+    static const furvm::byte s_bytecode[] = {
+        static_cast<furvm::byte>(furvm::instruction_t::Array),
+        1,
+        0,
+        0,
+        0,
+        static_cast<furvm::byte>(furvm::instruction_t::Reference),
+        static_cast<furvm::byte>(furvm::instruction_t::Lengthof),
+        static_cast<furvm::byte>(furvm::instruction_t::Call),
+        1,
+        0,
+        static_cast<furvm::byte>(furvm::instruction_t::Drop),
+        static_cast<furvm::byte>(furvm::instruction_t::Return),
+    };
 
-    mod->set_native_function("print",
-        [](furvm::executor& executor) { std::cout << executor.load_thing(0)->integer() << '\n'; });
+    auto mod       = context->emplace("main", s_bytecode, s_bytecode + sizeof(s_bytecode));
+    auto charType  = mod->emplace_type(furvm::mod_type::S8);
+    auto arrayType = mod->emplace_type(charType.id(), 10);
+    auto u64Type   = mod->emplace_type(furvm::mod_type::U64);
+    auto mainFunc  = mod->emplace_function("main", furvm::function_sig{}, 0);
+    mod->emplace_function(furvm::function_sig{ { u64Type }, u64Type }, "print").dispatch();
+#endif
+    mod->set_native_function("println", [](furvm::executor& executor) {
+        auto arg = executor.load_thing(0);
+        print_thing(*arg);
+        std::cout << '\n';
+    });
 
     furvm::executor_h executor = context->emplace_executor(context);
-    executor->push_frame(mod, *func);
+    executor->push_frame(mod, *mainFunc);
 
     while ((executor->flags() & furvm::executor_flags::Done) != furvm::executor_flags::Done) {
         executor->step();

furvm/src/module.cpp

@@ -1,13 +1,12 @@
 #include "furvm/module.hpp"
 
 #include "furvm/detail/serialization.hpp"
+#include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
-#include "furvm/type.hpp"
 
 #include <cstdint>
 #include <cstring>
 #include <ios>
-#include <memory>
 #include <stdexcept>
 #include <utility>
 
@@ -17,6 +16,39 @@ std::ostream& mod::serialize(std::ostream& os) const {
     os.write(MAGIC, sizeof(MAGIC));
     detail::serialize(os, std::uint32_t(0)); // version
 
+    mod_type_id typeCount = mod_type_id(m_types.cend() - m_types.cbegin());
+    detail::serialize(os, typeCount);
+    for (mod_type_id id = 0; id < typeCount; ++id) {
+        if (!m_types.contains(id)) {
+            detail::serialize(os, std::uint8_t(0xFF)); // null type
+            continue;
+        }
+
+        auto type = *m_types.at(id);
+        detail::serialize(os, static_cast<std::uint8_t>(type.type));
+        switch (type.type) {
+        case mod_type::S8:
+        case mod_type::S16:
+        case mod_type::S32:
+        case mod_type::S64:
+        case mod_type::U8:
+        case mod_type::U16:
+        case mod_type::U32:
+        case mod_type::U64: break;
+        case mod_type::Ptr:
+        case mod_type::Ref: detail::serialize(os, type.value.typeRef); break;
+        case mod_type::Array: {
+            detail::serialize(os, type.value.array.typeId);
+            detail::serialize(os, type.value.array.size);
+        } break;
+        case mod_type::Import: {
+            detail::serialize(os, type.value.imprt.modId);
+            detail::serialize(os, type.value.imprt.typeId);
+        } break;
+        case mod_type::Count: throw std::runtime_error("unreachable");
+        }
+    }
+
     function_id funcCount = m_functions.cend() - m_functions.cbegin();
     detail::serialize(os, funcCount);
     for (function_id id = 0; id < funcCount; ++id) {
@@ -27,10 +59,20 @@ std::ostream& mod::serialize(std::ostream& os) const {
             continue;
         }
 
+        // Function name
         function_h func = m_functions.at(id);
-        bool       isPublic = m_publicFunctions.find(func->name()) != m_publicFunctions.end();
-        detail::serialize(os, isPublic ? func->name() : ""); // private functions have empty names
-        detail::serialize(os, func->param_count());
+        if (auto it = m_functionMap.find(func.id()); it != m_functionMap.end()) {
+            detail::serialize(os, it->second.first);
+        } else {
+            detail::serialize(os, "");
+        }
+
+        // Function signature
+        detail::serialize(os, static_cast<std::uint32_t>(func->signature().params.size()));
+        for (std::uint32_t i = 0; i < func->signature().params.size(); ++i)
+            detail::serialize(os, func->signature().params[i].id());
+
+        // Function body/value
         detail::serialize(os, std::uint8_t(func->type()));
         switch (func->type()) {
         case function_t::Normal: {
@@ -46,26 +88,6 @@ std::ostream& mod::serialize(std::ostream& os) const {
         }
     }
 
-    type_id typeCount = type_id(m_types.cend() - m_types.cbegin());
-    detail::serialize(os, typeCount);
-    for (type_id id = 0; id < typeCount; ++id) {
-        if (!m_types.contains(id)) {
-            detail::serialize(os, std::uint8_t(0xFF)); // null type
-            continue;
-        }
-
-        auto type = *m_types.at(id);
-        switch (type->t) {
-        case type_t::Primitive: detail::serialize(os, type->primitive); break;
-        case type_t::Reference: throw std::runtime_error("reference type serialization is unimplemented");
-        case type_t::List: detail::serialize(os, type->list.id()); break;
-        case type_t::Import: {
-            detail::serialize(os, type->imp.mod);
-            detail::serialize(os, type->imp.type);
-        } break;
-        }
-    }
-
     detail::serialize(os, std::uint64_t(m_bytecode.size()));
     return os.write(reinterpret_cast<const char*>(m_bytecode.data()), static_cast<std::streamsize>(m_bytecode.size()));
 }
@@ -80,13 +102,64 @@ mod mod::load(std::istream& is) {
 
     mod mod;
 
+    mod_type_id typeCount = 0;
+    detail::load(is, typeCount);
+    for (mod_type_id id = 0; id < typeCount; ++id) {
+        std::uint8_t type = 0;
+        detail::load(is, type);
+        if (type == 0xFF) continue;
+
+        switch ((enum mod_type::type)type) {
+        case mod_type::S8:
+        case mod_type::S16:
+        case mod_type::S32:
+        case mod_type::S64:
+        case mod_type::U8:
+        case mod_type::U16:
+        case mod_type::U32:
+        case mod_type::U64: {
+            mod_type theType = { (enum mod_type::type)type };
+            mod.emplace_type(id, theType).dispatch();
+        } break;
+        case mod_type::Ptr: {
+            mod_type_id typeId = 0;
+            detail::load(is, typeId);
+            mod.emplace_type(id, typeId).dispatch();
+        } break;
+        case mod_type::Array: {
+            mod_type_id typeId = 0;
+            detail::load(is, typeId);
+            std::size_t size = 0;
+            detail::load(is, size);
+            mod.emplace_type(id, typeId, size).dispatch();
+        } break;
+        case mod_type::Import: {
+            std::string modName;
+            detail::load(is, modName);
+            mod_type_id typeId = 0;
+            detail::load(is, typeId);
+            mod.emplace_type(id, std::move(modName), typeId).dispatch();
+        } break;
+        default: throw std::runtime_error("unknown type type");
+        }
+    }
+
     function_id functionCount = 0;
     detail::load(is, functionCount);
     for (function_id id = 0; id < functionCount; ++id) {
         std::string name;
         detail::load(is, name);
+
+        function_sig  signature;
         std::uint32_t paramCount = 0;
         detail::load(is, paramCount);
+        signature.params.reserve(paramCount);
+        while (signature.params.size() < paramCount) {
+            thing_id param{ 0 };
+            detail::load(is, param);
+            signature.params.emplace_back(mod.type_at(param));
+        }
+
         std::uint8_t type = 0;
         detail::load(is, type);
         if (type == 0xFF) continue;
@@ -95,12 +168,18 @@ mod mod::load(std::istream& is) {
         case function_t::Normal: {
             decltype(std::declval<function>().position()) offset = 0;
             detail::load(is, offset);
-            mod.emplace_function(id, std::move(name), paramCount, offset).dispatch();
+            if (name.empty())
+                mod.emplace_function(id, std::move(signature), offset).dispatch();
+            else
+                mod.emplace_function(std::move(name), id, std::move(signature), offset).dispatch();
         } break;
         case function_t::Native: {
             std::string native;
             detail::load(is, native);
-            mod.emplace_function(id, std::move(name), paramCount, std::move(native)).dispatch();
+            if (name.empty())
+                mod.emplace_function(id, std::move(signature), std::move(native)).dispatch();
+            else
+                mod.emplace_function(std::move(name), id, std::move(signature), std::move(native)).dispatch();
         } break;
         case function_t::Import: {
             std::string modName;
@@ -113,36 +192,6 @@ mod mod::load(std::istream& is) {
         }
     }
 
-    type_id typeCount = 0;
-    detail::load(is, typeCount);
-    for (type_id id = 0; id < typeCount; ++id) {
-        std::uint8_t type = 0;
-        detail::load(is, type);
-        if (type == 0xFF) continue;
-
-        switch ((type_t)type) {
-        case type_t::Primitive: {
-            primitive_type primitive = 0;
-            detail::load(is, primitive);
-            mod.emplace_type(id, std::make_shared<class type>(primitive)).dispatch();
-        } break;
-        case type_t::Reference: throw std::runtime_error("reference type serialization is unimplemented");
-        case type_t::List: {
-            type_id typeId = 0;
-            detail::load(is, typeId);
-            mod.emplace_type(id, std::make_shared<class type>(mod.type_at(typeId))).dispatch();
-        } break;
-        case type_t::Import: {
-            std::string modName;
-            detail::load(is, modName);
-            type_id typeId = 0;
-            detail::load(is, typeId);
-            mod.emplace_type(id, std::make_shared<class type>(import_type{ std::move(modName), typeId })).dispatch();
-        } break;
-        default: throw std::runtime_error("unknown type type");
-        }
-    }
-
     std::uint64_t bytecodeLength = 0;
     detail::load(is, bytecodeLength);
     mod.bytecode().resize(bytecodeLength);

furvm/test/test.cpp

@@ -1,3 +1,28 @@
+#include "furlang/arena.hpp"
+#include "furvm/furvm.hpp"
+#include "furvm/thing.hpp"
+#include "furvm/thing_allocator.hpp"
+
 #include "gtest/gtest.h" // IWYU pragma: keep
 
-namespace {}
+namespace {
+
+// TODO: Basic program tests (e.g. for loops)
+
+TEST(Things, Ops) {
+    furlang::arena                    arena;
+    furvm::thing_allocator<std::byte> alloc{ arena };
+
+    furvm::thing lhs{ furvm::thing_type{ furvm::thing_type::U32 }, alloc };
+    lhs.get<furvm::thing_type::u32>() = 6;
+    furvm::thing rhs{ furvm::thing_type{ furvm::thing_type::U32 }, alloc };
+    rhs.get<furvm::thing_type::u32>() = 7;
+
+    auto res = lhs.add(rhs);
+    ASSERT_EQ(res.type().type, furvm::thing_type::U32);
+    EXPECT_EQ(lhs.get<furvm::thing_type::u32>(), 6);
+    EXPECT_EQ(rhs.get<furvm::thing_type::u32>(), 7);
+    EXPECT_EQ(res.get<furvm::thing_type::u32>(), 6 + 7);
+}
+
+} // namespace