Optionally Write Keys at Runtime (while using Partials) about glaze HOT 2 OPEN

Thanks for explaining your problem in detail. We can still have compile time hash tables with runtime inclusion/exclusion, since we know our potential keys at compile time.

The problem with runtime JSON pointers to keys is that this induces runtime sorting and grouping, which is a significant cost. But, I'm sure you're looking for flexibility and not peak performance.

Better performance can be achieved if we don't use JSON pointers and only allow top level keys.

Do you find yourself using nested partial writing? Or, would you be satisfied with only top level keys in an object being specified?

Potential API:

std::vector<std::string> keys = { "key_one", "key_two" };
glz::write_partial_json(keys, object, buffer);

from glaze.

We're only writing top level keys for the foreseeable future, so this would be a nice enhancement.

That api is pretty much what I want to do. I'd love to keep the compile time key performance, but It would be nice to set flags in my struct that indicate which known compile time keys that should be ignored during serialization (you have a flags() method available in glz::meta but Im not sure it solves my use case):

static constexpr auto value = flags("my-conditional-key", &T::bSerializeConditionalKey); // this seems to only work for the field bSerializeConditionalKey itself, not another field with a real value.

Something like:

struct myData
{
  bool bField1Flag{false};
  bool bField2Flag{false};

 char someField1[]
 char someField2[]
}


template <>
struct meta<myData>
{
using T = myData;

  static constexpr auto value = object("field-1", , glz::custom<read_field_1  , write_field1
, true                     // always read
, &T::bFieldFlag1 // runtime conditionally write
>.
}

from glaze.