#kupas/orjson

#Usage

///|
test {
  let json = @orjson.parse("{\"a\": [1, 2.5, true, null]}")
  let text = @orjson.stringify(json)
  assert_eq(text, "{\"a\":[1,2.5,true,null]}")

  // indented output with sorted keys (like OPT_INDENT_2 | OPT_SORT_KEYS)
  let pretty = @orjson.stringify_with(json, indent=2, sort_keys=true)
  assert_eq(
    pretty, "{\n  \"a\": [\n    1,\n    2.5,\n    true,\n    null\n  ]\n}",
  )
}

#API

• parse(String) -> Json raise JsonError — parse a JSON document (mirrors orjson.loads(str)). Strings containing lone surrogates are rejected.
• parse_bytes(Bytes) -> Json raise JsonError — parse UTF-8 bytes (mirrors orjson.loads(bytes)). Invalid UTF-8 is rejected.
• stringify(Json) -> String raise JsonError — compact output (mirrors orjson.dumps).
• stringify_with(Json, indent~, sort_keys~, append_newline~) -> String raise JsonError — indent=2 matches orjson.OPT_INDENT_2, sort_keys=true matches orjson.OPT_SORT_KEYS, append_newline=true matches orjson.OPT_APPEND_NEWLINE.

#orjson compatibility

• Strict RFC 8259 parsing: comments, trailing commas, NaN/Infinity literals and other non-standard extensions are rejected.
• Non-negative integers decode as UInt, negative integers as Int, and numbers outside the 64-bit integer ranges decode as Float.
• Strings are escaped exactly like orjson (\b, \f, \n, \r, \t, lowercase \u00xx for other control characters, raw UTF-8 elsewhere).
• Doubles use orjson's shortest-round-trip formatting: scientific notation when the decimal exponent is >= 16 or <= -6, with an explicit sign (1e+16, 1e-6) and a .0 suffix for integral values (1.0). NaN and infinities serialize as null.
• Decode errors carry orjson's message format {message}: line {line} column {column} (char {pos}) and the 0-based character position.
• Nesting limits match orjson: parse depth 1024, serialize depth 254 (Recursion limit reached).
• Duplicate object keys keep the last value; Raw fragments are never validated.

#Differences from orjson

• Object dumping follows MoonBit Map iteration order unless sort_keys=true (orjson preserves dict insertion order).
• int/float are separated into Int/UInt/Float constructors (orjson uses Python's arbitrary-precision int).
• The package is native-only.

#Layout

• orjson.mbt — public API.
• ffi.mbt — extern declarations of the C bridge.
• orjson_test.mbt — hand-written unit tests.
• orjson_diff_test.mbt, orjson_err_diff_test.mbt — generated differential tests that compare outputs and decode errors byte-for-byte against orjson 3.13.0.
• c/bridge.c — the C bridge (tree, parser, accessors, serializer).
• c/yyjson_impl.c, c/yyjson_conf.h — compile the vendored yyjson with orjson-compatible settings.
• vendor/yyjson/ — yyjson as vendored and modified by orjson (MIT; see vendor/README.md and the license files under vendor/).