OpenAI result_format JSON

[ryanpeach]

Is your feature request related to a problem? Please describe.

OpenAI now provides a JSON response format! https://community.openai.com/t/how-do-i-use-the-new-json-mode/475890/14

Since OpenAI does not support enforced grammar, this is a big deal.

Describe the solution you'd like

The json grammar should trigger this functionality in the OpenAIChatEngine

[ryanpeach]

Relevant lines of code:

guidance/guidance/models/_openai.py

Lines 243 to 251 in 7c71e90

	generator = self.client.chat.completions.create(
	model=self.model_name,
	messages=messages,
	max_tokens=self.max_streaming_tokens,
	n=1,
	top_p=1.0,# TODO: this should be controllable like temp (from the grammar)
	temperature=temperature,
	stream=True
	)

guidance/guidance/library/_json.py

Lines 204 to 211 in 7c71e90

	@guidance(stateless=True)
	def json(lm, json_schema: Mapping[str, Any], name: Optional[str] = None):
	_DEFS_KEY = "$defs"
	definitions = {}
	if _DEFS_KEY in json_schema:
	definitions = _build_definitions(json_schema[_DEFS_KEY])
	return lm + guidance.capture(_gen_json(json_schema, definitions), name=name)

[ryanpeach]

Need to upgrade openai to 1.1 based on openai/openai-python@v1.0.1...v1.1.0

[ryanpeach]

Relevant api link https://platform.openai.com/docs/api-reference/chat/create#chat-create-response_format

[ryanpeach]

Related PR's #699 #724