Docstring parsing using docstring-parser (#76)

* adds description for params

* add test for missing param description

* adds docstring parsing to OpenAISchema

* docs

---------

Co-authored-by: Jason Liu <jxnl@users.noreply.github.com>

tests/test_function_calls.py

@@ -1,7 +1,9 @@
+from typing import Literal
+
 import pytest
 from pydantic import BaseModel
 
-from instructor import openai_schema, OpenAISchema
+from instructor import openai_schema, OpenAISchema, openai_function
 
 
 def test_openai_schema():
@@ -40,3 +42,48 @@ def test_no_docstring():
         Dummy.openai_schema["description"]
         == "Correctly extracted `Dummy` with all the required parameters with correct types"
     )
+
+
+def test_openai_function():
+    @openai_function
+    def get_current_weather(
+            location: str, format: Literal["celsius", "fahrenheit"] = "celsius"
+    ):
+        """
+        Gets the current weather in a given location, use this function for any questions related to the weather
+
+        Parameters
+        ----------
+        location
+            The city to get the weather, e.g. San Francisco. Guess the location from user messages
+
+        format
+            A string with the full content of what the given role said
+        """
+
+    @openai_function
+    def get_current_weather_no_format_docstring(
+            location: str, format: Literal["celsius", "fahrenheit"] = "celsius"
+    ):
+        """
+        Gets the current weather in a given location, use this function for any questions related to the weather
+
+        Parameters
+        ----------
+        location
+            The city to get the weather, e.g. San Francisco. Guess the location from user messages
+        """
+
+    scheme_missing_param = get_current_weather_no_format_docstring.openai_schema
+    assert (
+        scheme_missing_param["parameters"]["properties"]["location"]["description"]
+        ==
+        "The city to get the weather, e.g. San Francisco. Guess the location from user messages"
+    )
+    assert (
+        scheme_missing_param["parameters"]["properties"]["format"]["enum"]
+        ==
+        ["celsius", "fahrenheit"]
+    )
+    with pytest.raises(KeyError, match="description"):
+        scheme_missing_param["parameters"]["properties"]["format"]["description"]