Erlang External Term Format

Glaze optionally supports the Erlang External Term Format, abbreviated as EETF.

The Glaze CMake provides the option: glaze_EETF_FORMAT. Enable this option to link in the require Erlang libraries.

In the long term the goal is to remove the requirement on the Erlang libraries, but they are required for now.

If you are not using CMake the macro GLZ_ENABLE_EETF must be added to utilize Glaze's EETF headers. The glaze_EETF_FORMAT will add the GLZ_ENABLE_EETF macro if selected.

See Unit Tests

EETF to JSON Conversion

glz::eetf_to_json converts a buffer of Erlang terms directly to a buffer of JSON.

std::string json{};
auto ec = glz::eetf_to_json(term, json);

binary_as_base64 is off by default, so an Erlang binary is written as a JSON string. Binaries hold arbitrary bytes, and a control character (0x00–1F) among them has no short JSON escape, so the conversion fails with error_code::invalid_control_character.

Two ways across:

// binary_as_base64 is a member of eetf_opts, so set it inline.
// Usually the right answer for a binary: no raw bytes end up in a JSON string.
glz::eetf_to_json<glz::eetf::eetf_opts{.binary_as_base64 = true}>(term, json);

// escape_control_characters is inheritable, so add it to a custom opts struct.
// Keeps the bytes as JSON string content, escaped.
struct escaping : glz::eetf::eetf_opts {
   bool escape_control_characters = true;
};
glz::eetf_to_json<escaping{}>(term, json);

See String Escaping.

Only strings, atoms, and binaries work as object keys, since a JSON key must be a string. The atoms true and false are written as bare JSON literals, except as a key, where they stay quoted.