Use function instead of FunctionCall in FunctionResultMessage

[jackmpcollins]

Warning

Breaking Change: FunctionResultMessage init param function_call: FunctionCall replaced by function: Callable

Only the name of the function is needed when serializing the FunctionResultMessage so we do not need the whole FunctionCall. This simplifies creating @chatprompt function where the chat contains a function call. e.g.

from magentic import (
    chatprompt,
    AssistantMessage,
    UserMessage,
    FunctionCall,
    FunctionResultMessage,
)


def plus(a: int, b: int) -> int:
    return a + b


@chatprompt(
    UserMessage("Use the plus function to add 1 and 2."),
    AssistantMessage(FunctionCall(plus, 1, 2)),
    FunctionResultMessage(3, plus),
)
def do_math() -> str:
    ...


do_math()
# 'The sum of 1 and 2 is 3.'

Also

• Add test for message_to_openai_message
• Fix: function name when serializing FunctionResultMessage