purescript-cpp-create-game.md

Unboxing in the Last Lambda Function

exports["setScale"] = [](const boxed& nodePath_) -> boxed {
  return [=](const boxed& x_) -> boxed {
    return [=](const boxed& y_) -> boxed {
      return [=](const boxed& z_) -> boxed {
        return [=]() -> boxed {
          auto nodePath = unbox<NodePath>(nodePath_);
          const auto x = unbox<double>(x_);
          const auto y = unbox<double>(y_);
          const auto z = unbox<double>(z_);
          nodePath.set_scale(x, y, z);
          return boxed();
        };
      };
    };
  };
};

Unboxing in the First Lambda Function and Capturing by Reference

exports["setScale"] = [](const boxed& nodePath_) -> boxed {
  auto nodePath = unbox<NodePath>(nodePath_);
  return [&](const boxed& x_) -> boxed {
    const auto x = unbox<double>(x_);
    return [&](const boxed& y_) -> boxed {
      const auto y = unbox<double>(y_);
      return [&](const boxed& z_) -> boxed {
        const auto z = unbox<double>(z_);
        return [&]() -> boxed {
          nodePath.set_scale(x, y, z);
          return boxed();
        };
      };
    };
  };
};

Trying to Mutate a Constant NodePath

exports["setScale"] = [](const boxed& nodePath_) -> boxed {
  auto nodePath = unbox<NodePath>(nodePath_);
  return [=](const boxed& x_) -> boxed {
    const auto x = unbox<double>(x_);
    return [=](const boxed& y_) -> boxed {
      const auto y = unbox<double>(y_);
      return [=](const boxed& z_) -> boxed {
        const auto z = unbox<double>(z_);
        return [=]() -> boxed {
          nodePath.set_scale(x, y, z);
          return boxed();
        };
      };
    };
  };
};

Using the Mutable Keyword

exports["setScale"] = [](const boxed& nodePath_) -> boxed {
  auto nodePath = unbox<NodePath>(nodePath_);
  return [=](const boxed& x_) mutable -> boxed {
    const auto x = unbox<double>(x_);
    return [=](const boxed& y_) mutable -> boxed {
      const auto y = unbox<double>(y_);
      return [=](const boxed& z_) mutable -> boxed {
        const auto z = unbox<double>(z_);
        return [=]() mutable -> boxed {
          nodePath.set_scale(x, y, z);
          return boxed();
        };
      };
    };
  };
};

Creating an Ambient Light

exports["createAmbientLight"] = [](const boxed& s_) -> boxed {
  return [&](const boxed& r_) -> boxed {
    return [&](const boxed& g_) -> boxed {
      return [&](const boxed& b_) -> boxed {
        return [&]() -> boxed {
          const auto s = unbox<string>(s_);
          const auto r = unbox<double>(r_);
          const auto g = unbox<double>(g_);
          const auto b = unbox<double>(b_);
          AmbientLight* l = new AmbientLight(s);
          l->set_color(LVecBase4f(r, g, b, 1));
          PandaNode* pandaNode = l->as_node();
          return box<PandaNode*>(pandaNode);
        };
      };
    };
  };
};