feat!: add function calling support to client.chat() & client.chat_async()

BREAKING CHANGE: Too many to count in this version. Check the README examples.

examples/chat_with_function_calling_async.rs

@@ -0,0 +1,75 @@
+use mistralai_client::v1::{
+    chat::{ChatMessage, ChatMessageRole, ChatParams},
+    client::Client,
+    constants::Model,
+    tool::{Function, Tool, ToolChoice, ToolFunctionParameter, ToolFunctionParameterType},
+};
+use serde::Deserialize;
+use std::any::Any;
+
+#[derive(Debug, Deserialize)]
+struct GetCityTemperatureArguments {
+    city: String,
+}
+
+struct GetCityTemperatureFunction;
+#[async_trait::async_trait]
+impl Function for GetCityTemperatureFunction {
+    async fn execute(&self, arguments: String) -> Box<dyn Any + Send> {
+        // Deserialize arguments, perform the logic, and return the result
+        let GetCityTemperatureArguments { city } = serde_json::from_str(&arguments).unwrap();
+
+        let temperature = match city.as_str() {
+            "Paris" => "20°C",
+            _ => "Unknown city",
+        };
+
+        Box::new(temperature.to_string())
+    }
+}
+
+#[tokio::main]
+async fn main() {
+    let tools = vec![Tool::new(
+        "get_city_temperature".to_string(),
+        "Get the current temperature in a city.".to_string(),
+        vec![ToolFunctionParameter::new(
+            "city".to_string(),
+            "The name of the city.".to_string(),
+            ToolFunctionParameterType::String,
+        )],
+    )];
+
+    // This example suppose you have set the `MISTRAL_API_KEY` environment variable.
+    let mut client = Client::new(None, None, None, None).unwrap();
+    client.register_function(
+        "get_city_temperature".to_string(),
+        Box::new(GetCityTemperatureFunction),
+    );
+
+    let model = Model::MistralSmallLatest;
+    let messages = vec![ChatMessage {
+        role: ChatMessageRole::User,
+        content: "What's the temperature in Paris?".to_string(),
+        tool_calls: None,
+    }];
+    let options = ChatParams {
+        temperature: Some(0.0),
+        random_seed: Some(42),
+        tool_choice: Some(ToolChoice::Auto),
+        tools: Some(tools),
+        ..Default::default()
+    };
+
+    client
+        .chat_async(model, messages, Some(options))
+        .await
+        .unwrap();
+    let temperature = client
+        .get_last_function_call_result()
+        .unwrap()
+        .downcast::<String>()
+        .unwrap();
+    println!("The temperature in Paris is: {}.", temperature);
+    // => "The temperature in Paris is: 20°C."
+}