From 4718780d9d3e06f7e40db563a091a8b0965d44f6 Mon Sep 17 00:00:00 2001
From: Konstantin Nazarov <mail@knazarov.com>
Date: Sun, 28 Jul 2024 23:37:43 +0100
Subject: [PATCH] Make writer actually print something

This also fixes some of the GcRoot bugs
---
 src/arena.hpp  |  7 +++----
 src/common.cpp | 12 +++++++++++-
 src/common.hpp |  3 +++
 src/result.hpp | 28 ++++++++++++++++++++++++++--
 src/vli.cpp    |  3 +++
 5 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/src/arena.hpp b/src/arena.hpp
index 555d6fc..7f0b0f8 100644
--- a/src/arena.hpp
+++ b/src/arena.hpp
@@ -55,11 +55,10 @@ class GcRootList {
 
   GcRootList(GcRootBase* root) : _prev(0), _next(0), _root(root) {}
   void insert(GcRootList* node) {
-    GcRootList* next = _next;
-
-    _next = node;
-    node->_next = next;
+    node->_next = _next;
     node->_prev = this;
+    if (_next) _next->_prev = node;
+    _next = node;
   }
 
   void remove() {
diff --git a/src/common.cpp b/src/common.cpp
index 2cd7772..e1c3b3e 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -52,6 +52,7 @@ Result<ByteArray> ByteArray::create(Arena& arena, String& str) {
     size += utf8_codepoint_size(TRY(str[i]));
   }
   auto pod = TRY(arena.alloc<PodByteArray>(size * sizeof(char)));
+  pod->size = size;
 
   char* res = pod->data;
   for (uint64_t i = 0; i < str.size(); i++) {
@@ -59,7 +60,6 @@ Result<ByteArray> ByteArray::create(Arena& arena, String& str) {
     size = utf8_codepoint_size(codepoint);
     res = utf8_write_codepoint(res, codepoint);
   }
-  pod->size = size;
 
   return ByteArray(TRY(MkGcRoot(pod, arena)));
 }
@@ -137,3 +137,13 @@ Result<Value> reverse(Arena& arena, Value& val) {
 
   return res;
 }
+
+Result<void> debug_print(Arena& arena, String& val) {
+  auto ba = TRY(ByteArray::create(arena, val));
+
+  for (uint64_t i = 0; i < ba.size(); i++) {
+    std::cout << TRY(ba[i]);
+  }
+  std::cout << "\n";
+  return Result<void>();
+}
diff --git a/src/common.hpp b/src/common.hpp
index d21ec9e..40c0df4 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -423,6 +423,7 @@ class Value {
   }
 
   Value& operator=(Value&& val) {
+    ((Object*)buf)->~Object();
     memcpy(buf, val.buf, 24);
     new (val.buf) Nil();
     return *this;
@@ -455,3 +456,5 @@ class Value {
 Result<Value> syntax_unwrap(Value& val);
 
 Result<Value> reverse(Arena& arena, Value& val);
+
+Result<void> debug_print(Arena& arena, String& val);
diff --git a/src/result.hpp b/src/result.hpp
index 3a0e32f..4e4f120 100644
--- a/src/result.hpp
+++ b/src/result.hpp
@@ -7,8 +7,8 @@
 template <class T>
 class Result {
  public:
-  Result(const T& res) : _value(res) {}
-  Result(T&& res) : _value(std::move(res)) {}
+  Result(const T& res) : _value(res), _error(ErrorCode::Success) {}
+  Result(T&& res) : _value(std::move(res)), _error(ErrorCode::Success) {}
   Result(ErrorCode err) : _error(err) {}
 
   bool has_error() { return _error != ErrorCode::Success; }
@@ -24,6 +24,30 @@ class Result {
   ErrorCode _error;
 };
 
+template <>
+class Result<void> {
+ public:
+  using ResultType = void;
+
+  Result(Result&& res) = default;
+
+  Result(ErrorCode err) : err(err) {}
+  Result() : err(ErrorCode::Success) {}
+
+  Result& operator=(Result&& res) = default;
+
+  bool has_error() { return err != ErrorCode::Success; }
+  bool has_value() { return !has_error(); }
+
+  void value() {}
+  void release_value() {}
+
+  ErrorCode error() { return err; }
+
+ private:
+  ErrorCode err;
+};
+
 #define TRY(m)                                       \
   (({                                                \
      auto ___res = (m);                              \
diff --git a/src/vli.cpp b/src/vli.cpp
index 2cb020e..662bcde 100644
--- a/src/vli.cpp
+++ b/src/vli.cpp
@@ -36,5 +36,8 @@ int main() {
   auto writer = Writer(arena);
   auto s2 = DIEIF(writer.write_one(r));
 
+  std::cout << "size: " << s.size() << "\n";
+  std::cout << "char: " << (char)DIEIF(s[0]) << "\n";
+  DIEIF(debug_print(arena, s2));
   return 0;
 }