this code is a mess and I am losing my mind

This commit does not work and I am so down I don't even bother
committing to conventional commits until I fix this mess.

furas/examples/array.furas

@@ -1,23 +1,34 @@
-type arr = array $s8 11
+type arr = array $s8 10
 
 func println $arr = native println
 
 public func main = #main
 main:
     array $arr
+    dup
     store %0
+
+    lenof
+    push $s32 1
+    sub
+    store %1
+
     push $s32 0
 loop:
     dup
-    push $s32 10
+    load %1
     eq
     jnz #end
 body:
     dup
     load %0
+    swap
     push $s8 69
     set
 
+    push $s32 1
+    add
+
     jmp #loop
 end:
     drop

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 1
+    store %1
+
+    push $s32 0
+loop:
+    dup
+    load %1
+    eq
+    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/token.hpp

@@ -37,6 +37,7 @@ struct token {
         Set,
         Drop,
         Dup,
+        Swap,
         Clone,
         Ref,
         Add,

furas/src/gen.cpp

@@ -40,6 +40,7 @@ std::unordered_map<enum token::type, instruction> instructions = {
     { 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 } },
@@ -89,6 +90,7 @@ const char* token_type(enum token::type type) {
     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";
@@ -384,27 +386,36 @@ struct mod_context {
             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) };
@@ -417,6 +428,7 @@ struct mod_context {
         case token::Set:
         case token::Drop:
         case token::Dup:
+        case token::Swap:
         case token::Clone:
         case token::Ref:
         case token::Add:
@@ -503,7 +515,7 @@ struct mod_context {
                     mod.bytecode().push_back(0);
                     return { generator_error::Success };
                 }
-                std::ptrdiff_t jmpOff = static_cast<std::ptrdiff_t>(offset - mod.bytecode().size() + 1);
+                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

furas/src/lexer.cpp

@@ -46,6 +46,7 @@ token_r lexer::next_token() {
         { "set", token::Set },
         { "drop", token::Drop },
         { "dup", token::Dup },
+        { "swap", token::Swap },
         { "clone", token::Clone },
         { "ref", token::Ref },
         { "add", token::Add },

furvm/include/furvm/fwd.hpp

@@ -111,7 +111,7 @@ using function_id = std::uint16_t;
 /**
  * @brief A handle to a furvm function.
  */
-using function_h = handle<function, refcount_header<function_id>>;
+using function_h = handle<function, generic_header<function_id>>;
 
 // module.hpp
 

furvm/include/furvm/instruction.hpp

@@ -76,6 +76,11 @@ enum class instruction_t : byte {
      */
     Duplicate,
 
+    /**
+     * @brief Swaps two top elements of the stack.
+     */
+    Swap,
+
     /**
      * @brief Clones top element on the stack.
      */

furvm/include/furvm/thing.hpp

@@ -502,6 +502,32 @@ public:
         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 thing_type& arrayType, array& dst, const array& src) {
         if (arrayType.type != thing_type::Array || arrayType.value.array.type == nullptr)

furvm/src/executor.cpp

@@ -10,6 +10,7 @@
 #include <cassert>
 #include <cstdint>
 #include <stdexcept>
+#include <utility>
 #include <vector>
 
 namespace furvm {
@@ -122,7 +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() {
@@ -186,10 +187,10 @@ void executor::step() {
         push_thing(array->at(index->integer()));
     } break;
     case instruction_t::Set: {
-        auto index                  = pop_thing();
-        auto array                  = pop_thing();
-        auto element                = pop_thing();
-        array->at(index->integer()) = std::move(element->clone());
+        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();
@@ -197,6 +198,12 @@ 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;
@@ -316,7 +323,8 @@ 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++);

furvm/src/main.cpp

@@ -75,8 +75,8 @@ int main(int argc, char** argv) {
     mod->emplace_function(furvm::function_sig{ { u64Type }, u64Type }, "print").dispatch();
 #endif
     mod->set_native_function("println", [](furvm::executor& executor) {
-        auto arg = std::move(*executor.load_thing(0));
-        print_thing(arg);
+        auto arg = executor.load_thing(0);
+        print_thing(*arg);
         std::cout << '\n';
     });