stephenberry/glaze v5.3.1

on GitHub

First Missing Key Now Reported

When error_on_missing_keys = true we now report the first missing key.

Console output of glz::format_error when "hello" key is missing:

1:33: missing_key
   [{"i":287,"d":0.0,"arr":[1,2,3]}]
                                   ^ hello

• In #1766

New glz::cast wrapper for static casting fields

This provides cleaner syntax than using glz::custom.

glz::cast is a simple wrapper that will serialize and deserialize the cast type rather than underlying type. This enables the user to parse JSON for a floating point value into an integer, or perform similar static_cast behaviors.

struct cast_obj
{
   int integer{};
};

template <>
struct glz::meta<cast_obj>
{
   using T = cast_obj;
   static constexpr auto value = object("integer", cast<&T::integer, double>);
};

In use:

cast_obj obj{};
std::string buffer = R"({"integer":5.7})";
expect(not glz::read_json(obj, buffer));
expect(obj.integer == 5);

• In #1758

Integer IDs for std::variant

Previously only JSON strings could be used as IDs for std::variant. Now, this is possible:

struct Command401
{
   int code{};
   int indent{};
   std::vector<std::string> parameters{};
};

struct Command250Params
{
   std::string name{};
   int volume{};
   int pitch{};
   int pan{};
};

struct Command250
{
   int code{};
   int indent{};
   std::vector<Command250Params> parameters{};
};

using CommandVariant = std::variant<Command250, Command401>;

template <>
struct glz::meta<CommandVariant>
{
   static constexpr std::string_view tag = "code";
   static constexpr std::array ids = {250, 401};
};

Glaze will decode the proper type based on the tag's field, e.g. "code": 401 will parse a Command401 type.

• In #1764

Other Improvements

• Equality operators for glz::async_vector by @stephenberry in #1757

Fixes

• Remove bad unit test causing GCC 15 compilation failure by @stephenberry in #1763

Full Changelog: v5.3.0...v5.3.1