From ce65afa27791188edce8140f2f8ea9044983eabb Mon Sep 17 00:00:00 2001
From: Edward Shen <code@eddie.sh>
Date: Sun, 5 Apr 2020 13:31:05 -0400
Subject: [PATCH] use dynamic dispatch for actor selection

---
 src/cli.rs  | 10 +++++++---
 src/main.rs |  6 +++---
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/cli.rs b/src/cli.rs
index f1bd2e8..59c6abd 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -70,7 +70,8 @@ pub struct Train {
 arg_enum! {
     #[derive(Debug)]
     pub enum Agent {
-        QLearning
+        QLearning,
+        ApproximateQLearning,
     }
 }
 
@@ -87,6 +88,9 @@ pub fn init_verbosity(opts: &Opts) -> Result<(), Box<dyn std::error::Error>> {
     Ok(())
 }
 
-pub fn get_actor() -> impl Actor {
-    qlearning::QLearningAgent::default()
+pub fn get_actor(agent: Agent) -> Box<dyn Actor> {
+    match agent {
+        Agent::QLearning => Box::new(qlearning::QLearningAgent::default()),
+        Agent::ApproximateQLearning => todo!(),
+    }
 }
diff --git a/src/main.rs b/src/main.rs
index 00339c3..5bcf9bd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -33,7 +33,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     match opts.subcmd {
         SubCommand::Play(sub_opts) => {}
         SubCommand::Train(sub_opts) => {
-            let mut to_train = get_actor();
+            let mut to_train = get_actor(sub_opts.agent);
             to_train.set_learning_rate(sub_opts.learning_rate);
             to_train.set_discount_rate(sub_opts.discount_rate);
             to_train.set_exploration_prob(sub_opts.exploration_prob);
@@ -61,7 +61,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     Ok(())
 }
 
-fn train_actor(episodes: usize, mut actor: impl Actor) -> impl Actor {
+fn train_actor(episodes: usize, mut actor: Box<dyn Actor>) -> Box<dyn Actor> {
     let mut rng = rand::rngs::SmallRng::from_entropy();
     let mut avg = 0.0;
 
@@ -109,7 +109,7 @@ fn train_actor(episodes: usize, mut actor: impl Actor) -> impl Actor {
     actor
 }
 
-async fn play_game(mut actor: Option<impl Actor>) -> Result<(), Box<dyn std::error::Error>> {
+async fn play_game(mut actor: Option<Box<dyn Actor>>) -> Result<(), Box<dyn std::error::Error>> {
     let mut rng = rand::rngs::SmallRng::from_entropy();
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;