Switch to a resumption-style implementation for machines.

src/arcade.rs

@@ -1,35 +1,18 @@
-use crate::endchannel::{Receiver, Sender, channel};
-use crate::machine::Computer;
+use crate::machine::{Computer, RunResult};
 use terminal_graphics::{Colour, Display};
+use std::collections::VecDeque;
 use std::fmt;
-use std::thread;
 
 pub struct Arcade {
     screen: Vec<Tile>,
     width: usize,
     height: usize,
     pub score: usize,
-    joystick_port: Sender<i64>,
-    update_port: Receiver<Update>,
+    logic: Computer,
     ball: (usize, usize),
     paddle: (usize, usize),
 }
 
-pub fn auto_move(arcade: &Arcade) -> Move {
-    let (ball_x, _) = arcade.ball;
-    let (paddle_x, _) = arcade.paddle;
-
-    if paddle_x < ball_x {
-        return Move::Right;
-    }
-
-    if paddle_x > ball_x {
-        return Move::Left;
-    }
-
-    Move::Neutral
-}
-
 #[derive(Clone, Copy, Debug, PartialEq)]
 enum Tile {
     Empty,
@@ -39,13 +22,6 @@ enum Tile {
     Ball,
 }
 
-enum Update {
-    Score(usize),
-    Ball(usize, usize),
-    Paddle(usize, usize),
-    Draw(usize, usize, Tile),
-}
-
 impl fmt::Display for Tile {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
@@ -84,51 +60,72 @@ impl Tile {
 impl Arcade {
     pub fn new(width: usize, height: usize, cheat: bool, logic_file: &str) -> Arcade {
         let mut logic = Computer::load(logic_file);
-        let (    mysend, mut corecv) = channel();
-        let (mut cosend, mut myrecv) = channel();
-        let (mut upsend,     uprecv) = channel();
 
         if cheat { logic.write(0, 2); }
-        thread::spawn(move || logic.run(&mut corecv, &mut cosend));
-
         let mut screen = Vec::with_capacity(width * height);
         screen.resize(width * height, Tile::Empty);
-
-        thread::spawn(move || {
-            while let Some(first) = myrecv.recv() {
-                let second = myrecv.recv().expect("Didn't get second?!");
-                let third  = myrecv.recv().expect("Didn't get third?!");
-
-                if first == -1 && second == 0 {
-                    upsend.send_ignore_error(Update::Score(third as usize));
-                } else {
-                    let x = first as usize;
-                    let y = second as usize;
-                    let t = Tile::new(third);
-                    upsend.send_ignore_error(Update::Draw(x, y, t));
-                    if t == Tile::Ball             {
-                        upsend.send_ignore_error(Update::Ball(x, y));
-                    }
-                    if t == Tile::HorizontalPaddle {
-                        upsend.send_ignore_error(Update::Paddle(x, y));
-                    }
-                }
-            }
-            upsend.conclude();
-        });
-
         Arcade {
             screen,
             width,
             height,
-            joystick_port: mysend,
-            update_port: uprecv,
+            logic,
             score: 0,
             ball: (0, 0),
             paddle: (0, 0),
         }
     }
 
+    pub fn run<F: FnMut(&Arcade)>(mut self, mut redraw: F) -> Self {
+        let mut output_buffer = vec![];
+        let mut input_buffer = VecDeque::new();
+
+        loop {
+            match self.logic.run() {
+                RunResult::Continue(next) =>
+                    self.logic = next,
+                RunResult::Halted(next) => {
+                    self.logic = next;
+                    return self;
+                }
+                RunResult::Output(x, next) => {
+                    self.logic = next;
+                    output_buffer.push(x);
+                    if output_buffer.len() == 3 {
+                        if output_buffer[0] == -1 && output_buffer[1] == 0 {
+                            self.score = output_buffer[2] as usize;
+                        } else {
+                            let x = output_buffer[0] as usize;
+                            let y = output_buffer[1] as usize;
+                            let t = Tile::new(output_buffer[2]);
+                            self.screen[ (y * self.width) + x ] = t;
+                            if t == Tile::Ball {
+                                self.ball = (x, y);
+                                let (paddle_x, _) = self.paddle;
+
+                                if paddle_x < x {
+                                    input_buffer.push_back(Move::Right);
+                                } else if paddle_x > x {
+                                    input_buffer.push_back(Move::Left);
+                                } else {
+                                    input_buffer.push_back(Move::Neutral);
+                                }
+                            }
+                            if t == Tile::HorizontalPaddle {
+                                self.paddle = (x, y);
+                            }
+                        }
+                        output_buffer = vec![];
+                    }
+                }
+                RunResult::Input(c) => {
+                    self.logic = c(input_buffer.pop_front().unwrap().encode());
+                    redraw(&self);
+                }
+            }
+        }
+    }
+
+    #[cfg(test)]
     fn count_blocks(&self) -> usize {
         let mut count = 0;
 
@@ -141,39 +138,6 @@ impl Arcade {
         count
     }
 
-    pub fn process_update<F>(&mut self, next_move: F) -> bool
-         where F: Fn(&Arcade) -> Move
-    {
-        let next = self.update_port.recv();
-
-        if let Some(ref update) = next {
-            match update {
-                &Update::Score(s) => self.score = s,
-                &Update::Draw(x, y, t) => self.screen[ (y * self.width) + x ] = t,
-                &Update::Ball(x, y) => {
-                    self.ball = (x, y);
-                    let next = next_move(&self);
-                    self.paddle_move(next);
-                }
-                &Update::Paddle(x, y) => {
-                    self.paddle = (x, y);
-                //    let next = next_move(&self);
-                //    self.paddle_move(next);
-                }
-            }
-        }
-
-        next.is_some()
-    }
-
-    pub fn paddle_move(&mut self, motion: Move) {
-        match motion {
-            Move::Left    => self.joystick_port.send_ignore_error(-1),
-            Move::Neutral => self.joystick_port.send_ignore_error(0),
-            Move::Right   => self.joystick_port.send_ignore_error(1),
-        }
-    }
-
     pub fn draw(&self, display: &mut Display) {
         write_to_screen(display, 0, &format!("Score: {}", self.score));
         for row in 0..self.height {
@@ -202,13 +166,23 @@ pub enum Move {
     Right,
 }
 
+impl Move {
+    fn encode(&self) -> i64 {
+        match self {
+            Move::Left    => -1,
+            Move::Neutral => 0,
+            Move::Right   => 1,
+        }
+    }
+}
+
 #[test]
 fn day13() {
-    let mut arcade1 = Arcade::new(38, 21, false, "inputs/day13");
-    while arcade1.process_update(auto_move) { }
-    assert_eq!(301, arcade1.count_blocks());
+    let arcade1 = Arcade::new(38, 21, false, "inputs/day13");
+    let result1 = arcade1.run(|_| {});
+    assert_eq!(301, result1.count_blocks());
 
-    let mut arcade2 = Arcade::new(38, 21, true, "inputs/day13");
-    while arcade2.process_update(auto_move) { }
-    assert_eq!(14096, arcade2.score);
+    let arcade2 = Arcade::new(38, 21, true, "inputs/day13");
+    let result2 = arcade2.run(|_| {});
+    assert_eq!(14096, result2.score);
 }

src/machine.rs

@@ -1,9 +1,8 @@
-use crate::endchannel::{Sender, Receiver, channel};
+use std::collections::VecDeque;
 use std::fs;
 use std::iter::FromIterator;
 use std::ops::Range;
 use std::str;
-use std::thread;
 
 const ADD: i64         = 1;
 const MULTIPLY: i64    = 2;
@@ -42,6 +41,13 @@ pub struct Computer {
     done: bool
 }
 
+pub enum RunResult {
+    Input(Box<dyn FnOnce(i64) -> Computer>),
+    Output(i64, Computer),
+    Continue(Computer),
+    Halted(Computer),
+}
+
 impl Computer {
     pub fn load(path: &str) -> Computer {
         let byte_buffer = fs::read(path).unwrap();
@@ -108,7 +114,7 @@ impl Computer {
         self.memory[idx] = val;
     }
 
-    fn step(&mut self, input: &mut Receiver<i64>, output: &mut Sender<i64>) {
+    fn step(mut self) -> RunResult {
         let next_instruction = self.read(self.position);
         let opcode = next_instruction % 100;
         let arg1mode = Mode::from((next_instruction / 100) % 10);
@@ -123,6 +129,7 @@ impl Computer {
 
                 self.write(dest, arg1 + arg2);
                 self.position += 4;
+                RunResult::Continue(self)
             }
             MULTIPLY => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
@@ -131,26 +138,20 @@ impl Computer {
 
                 self.write(dest, arg1 * arg2);
                 self.position += 4;
+                RunResult::Continue(self)
             }
             INPUT => {
                 let dest = self.read_dest(arg1mode, self.position + 1) as usize;
-
-                match input.recv() {
-                    None => {
-                        output.conclude();
-                        self.done = true;
-                    }
-                    Some(val) => {
-                        self.write(dest, val);
                 self.position += 2;
-                    }
-                }
+                RunResult::Input(Box::new(move |x| {
+                    self.write(dest, x);
+                    self
+                }))
             }
             OUTPUT => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
-
-                output.send(arg1);
                 self.position += 2;
+                RunResult::Output(arg1, self)
             }
             JMPIF => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
@@ -161,6 +162,7 @@ impl Computer {
                 } else {
                     self.position += 3;
                 }
+                RunResult::Continue(self)
             }
             JMPNIF => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
@@ -171,6 +173,7 @@ impl Computer {
                 } else {
                     self.position += 3;
                 }
+                RunResult::Continue(self)
             }
             LESS_THAN => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
@@ -179,6 +182,7 @@ impl Computer {
 
                 self.write(dest, if arg1 < arg2 { 1 } else { 0 });
                 self.position += 4;
+                RunResult::Continue(self)
             }
             EQUALS => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
@@ -187,16 +191,18 @@ impl Computer {
 
                 self.write(dest, if arg1 == arg2 { 1 } else { 0 });
                 self.position += 4;
+                RunResult::Continue(self)
             }
             ADJUST_BASE => {
                 let arg1 = self.read_arg(arg1mode, self.position + 1);
 
                 self.relative_base += arg1;
                 self.position += 2;
+                RunResult::Continue(self)
             }
             HALT => {
-                output.conclude();
                 self.done = true;
+                RunResult::Halted(self)
             }
             /* */
             unknown_pos =>
@@ -204,29 +210,69 @@ impl Computer {
         }
     }
 
-    fn halted(&self) -> bool {
-        self.done
+    pub fn run(mut self) -> RunResult {
+        loop {
+            match self.step() {
+                RunResult::Continue(next) =>
+                    self = next,
+                result =>
+                    return result,
+            }
+        }
     }
 
-    pub fn run(&mut self, input: &mut Receiver<i64>, output: &mut Sender<i64>) {
-        while !self.halted() {
-            self.step(input, output);
+    pub fn standard_run(mut self, inputs: &[i64]) -> Vec<i64> {
+        let mut idx = 0;
+        let mut res = vec![];
+
+        loop {
+            match self.step() {
+                RunResult::Continue(next) =>
+                    self = next,
+                RunResult::Halted(_) =>
+                    return res,
+                RunResult::Input(c) if idx < inputs.len() => {
+                    self = c(inputs[idx]);
+                    idx += 1;
+                }
+                RunResult::Input(_) =>
+                    panic!("Ran out of inputs in standard run."),
+                RunResult::Output(x, next) => {
+                    res.push(x);
+                    self = next;
+                }
+            }
         }
     }
 
     pub fn serialize(&self, inputs: Vec<i64>) -> i64 {
-        let mut previous_output = vec![0];
+        let mut previous_output = VecDeque::new();
 
+        previous_output.push_back(0);
         for input in inputs.iter() {
-            let mut my_machine = self.clone();
-            let (    mysend, mut corecv) = channel();
-            let (mut cosend,     myrecv) = channel();
-            mysend.send(*input);
-            for i in previous_output.iter() {
-                mysend.send(*i);
+            let mut my_machine = self.clone().prime(*input);
+            let mut output = VecDeque::new();
+
+            loop {
+                match my_machine.run() {
+                    RunResult::Continue(next) =>
+                        my_machine = next,
+                    RunResult::Halted(_) =>
+                        break,
+                    RunResult::Input(c) =>
+                        match previous_output.pop_front() {
+                            None =>
+                                panic!("Serialized machine wanted input I didn't have!"),
+                            Some(next_input) =>
+                                my_machine = c(next_input),
+                        },
+                    RunResult::Output(o, next) => {
+                        output.push_back(o);
+                        my_machine = next;
                     }
-            my_machine.run(&mut corecv, &mut cosend);
-            previous_output = myrecv.collect();
+                }
+            }
+            previous_output = output;
         }
 
         assert_eq!(previous_output.len(), 1);
@@ -263,127 +309,143 @@ impl Computer {
         (best_score, best_result)
     }
 
+    pub fn prime(self, input: i64) -> Self {
+        match self.run() {
+            RunResult::Input(c) => c(input),
+            _                   =>
+                panic!("Priming failure: machine didn't ask for input first.")
+        }
+    }
+
     pub fn amplifier(&self, settings: Vec<i64>) -> i64 {
         assert_eq!(settings.len(), 5);
 
-        let mut machine_a = self.clone();
-        let mut machine_b = self.clone();
-        let mut machine_c = self.clone();
-        let mut machine_d = self.clone();
-        let mut machine_e = self.clone();
-
-        let (    send_ha, mut recv_ha) = channel(); send_ha.send(settings[0]);
-        let (mut send_ab, mut recv_ab) = channel(); send_ab.send(settings[1]);
-        let (mut send_bc, mut recv_bc) = channel(); send_bc.send(settings[2]);
-        let (mut send_cd, mut recv_cd) = channel(); send_cd.send(settings[3]);
-        let (mut send_de, mut recv_de) = channel(); send_de.send(settings[4]);
-        let (mut send_eh,     recv_eh) = channel();
-
-        thread::spawn(move || { machine_a.run(&mut recv_ha, &mut send_ab) });
-        thread::spawn(move || { machine_b.run(&mut recv_ab, &mut send_bc) });
-        thread::spawn(move || { machine_c.run(&mut recv_bc, &mut send_cd) });
-        thread::spawn(move || { machine_d.run(&mut recv_cd, &mut send_de) });
-        thread::spawn(move || { machine_e.run(&mut recv_de, &mut send_eh) });
-
-        send_ha.send(0); // kick it off
-
+        let mut machine_a = self.clone().prime(settings[0]);
+        let mut machine_b = self.clone().prime(settings[1]);
+        let mut machine_c = self.clone().prime(settings[2]);
+        let mut machine_d = self.clone().prime(settings[3]);
+        let mut machine_e = self.clone().prime(settings[4]);
         let mut last_output = 0;
 
-        for output in recv_eh {
-            last_output = output;
-            send_ha.send_ignore_error(output);
+        loop {
+            let aout = loop { match machine_a.run() {
+                RunResult::Halted(_) => return last_output,
+                RunResult::Output(o, next) => { machine_a = next; break o; }
+                RunResult::Input(c) => machine_a = c(last_output),
+                _ => panic!("Unexpted aout"),
+            } };
+            let bout = loop { match machine_b.run() {
+                RunResult::Halted(_) => return last_output,
+                RunResult::Output(o, next) => { machine_b = next; break o; }
+                RunResult::Input(c) => machine_b = c(aout),
+                _ => panic!("Unexpted aout"),
+            } };
+            let cout = loop { match machine_c.run() {
+                RunResult::Halted(_) => return last_output,
+                RunResult::Output(o, next) => { machine_c = next; break o; }
+                RunResult::Input(c) => machine_c = c(bout),
+                _ => panic!("Unexpted aout"),
+            } };
+            let dout = loop { match machine_d.run() {
+                RunResult::Halted(_) => return last_output,
+                RunResult::Output(o, next) => { machine_d = next; break o; }
+                RunResult::Input(c) => machine_d = c(cout),
+                _ => panic!("Unexpted aout"),
+            } };
+            let eout = loop { match machine_e.run() {
+                RunResult::Halted(_) => return last_output,
+                RunResult::Output(o, next) => { machine_e = next; break o; }
+                RunResult::Input(c) => machine_e = c(dout),
+                _ => panic!("Unexpted aout"),
+            } };
+            last_output = eout;
         }
-
-        last_output
     }
 }
 
 #[cfg(test)]
-fn run_example(computer: Vec<i64>, inputs: Vec<i64>, targets: Vec<i64>) {
+fn run_example(computer: Vec<i64>, inputs: &[i64], targets: &[i64]) {
     let day5a = Computer{ memory: computer, position: 0, relative_base: 0, done: false };
     run_computer(day5a, inputs, targets);
 }
 
 #[cfg(test)]
-fn run_computer(mut computer: Computer, inputs: Vec<i64>, targets: Vec<i64>) {
-    let (    mysend, mut corecv) = channel();
-    let (mut cosend,     myrecv) = channel();
-    for i in inputs.iter() {
-        mysend.send(*i);
-    }
-    computer.run(&mut corecv, &mut cosend);
-    let outputs: Vec<i64> = myrecv.collect();
-    assert_eq!(targets, outputs);
+fn run_computer(computer: Computer, inputs: &[i64], targets: &[i64]) {
+    let outputs = computer.standard_run(inputs);
+    assert_eq!(&outputs, &targets);
 }
 
 #[test]
 fn test_examples() {
-    let (mut deadsend, mut deadrecv) = channel();
-
-    let mut example1 = Computer::from_string("1,0,0,0,99");
+    let example1 = Computer::from_string("1,0,0,0,99");
     let answer1  = Computer{ memory: vec![2,0,0,0,99], position: 4, relative_base: 0, done: false };
-    example1.step(&mut deadrecv, &mut deadsend);
-    assert_eq!(example1, answer1);
+    match example1.step() {
+        RunResult::Continue(result) => assert_eq!(answer1, result),
+        _                           => assert!(false),
+    }
 
-    let mut example2 = Computer::from_string("2,3,0,3,99");
+    let example2 = Computer::from_string("2,3,0,3,99");
     let answer2 = Computer{ memory: vec![2,3,0,6,99], position: 4, relative_base: 0, done: false };
-    example2.step(&mut deadrecv, &mut deadsend);
-    assert_eq!(example2, answer2);
+    match example2.step() {
+        RunResult::Continue(result) => assert_eq!(answer2, result),
+        _                           => assert!(false),
+    }
 
-    let mut example3 = Computer::from_string("2,4,4,5,99,0");
+    let example3 = Computer::from_string("2,4,4,5,99,0");
     let answer3 = Computer{ memory: vec![2,4,4,5,99,9801], position: 4, relative_base: 0, done: false };
-    example3.step(&mut deadrecv, &mut deadsend);
-    assert_eq!(example3, answer3);
+    match example3.step() {
+        RunResult::Continue(result) => assert_eq!(answer3, result),
+        _                           => assert!(false),
+    }
 
-    let mut example4 = Computer::from_string("1,1,1,4,99,5,6,0,99");
+    let example4 = Computer::from_string("1,1,1,4,99,5,6,0,99");
     let answer4 = Computer{ memory: vec![30,1,1,4,2,5,6,0,99], position: 8, relative_base: 0, done: true };
-    example4.run(&mut deadrecv, &mut deadsend);
-    assert_eq!(example4, answer4);
-    assert!(example4.halted());
+    match example4.run() {
+        RunResult::Halted(result) => assert_eq!(answer4, result),
+        _                         => assert!(false),
+    }
 
-    let mut example5 = Computer::from_string("1002,4,3,4,33");
+    let example5 = Computer::from_string("1002,4,3,4,33");
     let answer5 = Computer{ memory: vec![1002,4,3,4,99], position: 4, relative_base: 0, done: true };
-    example5.run(&mut deadrecv, &mut deadsend);
-    assert_eq!(example5, answer5);
-    assert!(example5.halted());
+    match example5.run() {
+        RunResult::Halted(result) => assert_eq!(answer5, result),
+        _                         => assert!(false),
+    }
 
-    let mut example6 = Computer::from_string("1101,100,-1,4,0");
+    let example6 = Computer::from_string("1101,100,-1,4,0");
     let answer6 = Computer{ memory: vec![1101,100,-1,4,99], position: 4, relative_base: 0, done: true };
-    example6.run(&mut deadrecv, &mut deadsend);
-    assert_eq!(example6, answer6);
-    assert!(example6.halted());
+    match example6.run() {
+        RunResult::Halted(result) => assert_eq!(answer6, result),
+        _                         => assert!(false),
+    }
 
-    let mut day5a = Computer::load("inputs/day5");
+    let day5a = Computer::load("inputs/day5");
     let target = vec![0,0,0,0,0,0,0,0,0,7_259_358];
-    let (    mysend, mut corecv) = channel();
-    let (mut cosend,     myrecv) = channel();
-    mysend.send(1);
-    day5a.run(&mut corecv, &mut cosend);
-    let outputs: Vec<i64> = myrecv.collect();
+    let outputs = day5a.standard_run(&[1]);
     assert_eq!(target, outputs);
 
-    run_example(vec![3,9,8,9,10,9,4,9,99,-1,8], vec![8], vec![1]);
-    run_example(vec![3,9,8,9,10,9,4,9,99,-1,8], vec![9], vec![0]);
-    run_example(vec![3,9,7,9,10,9,4,9,99,-1,8], vec![4], vec![1]);
-    run_example(vec![3,9,7,9,10,9,4,9,99,-1,8], vec![8], vec![0]);
-    run_example(vec![3,9,7,9,10,9,4,9,99,-1,8], vec![9], vec![0]);
-    run_example(vec![3,3,1108,-1,8,3,4,3,99],   vec![8], vec![1]);
-    run_example(vec![3,3,1108,-1,8,3,4,3,99],   vec![9], vec![0]);
-    run_example(vec![3,3,1107,-1,8,3,4,3,99],   vec![4], vec![1]);
-    run_example(vec![3,3,1107,-1,8,3,4,3,99],   vec![8], vec![0]);
-    run_example(vec![3,3,1107,-1,8,3,4,3,99],   vec![9], vec![0]);
+    run_example(vec![3,9,8,9,10,9,4,9,99,-1,8], &[8], &[1]);
+    run_example(vec![3,9,8,9,10,9,4,9,99,-1,8], &[9], &[0]);
+    run_example(vec![3,9,7,9,10,9,4,9,99,-1,8], &[4], &[1]);
+    run_example(vec![3,9,7,9,10,9,4,9,99,-1,8], &[8], &[0]);
+    run_example(vec![3,9,7,9,10,9,4,9,99,-1,8], &[9], &[0]);
+    run_example(vec![3,3,1108,-1,8,3,4,3,99],   &[8], &[1]);
+    run_example(vec![3,3,1108,-1,8,3,4,3,99],   &[9], &[0]);
+    run_example(vec![3,3,1107,-1,8,3,4,3,99],   &[4], &[1]);
+    run_example(vec![3,3,1107,-1,8,3,4,3,99],   &[8], &[0]);
+    run_example(vec![3,3,1107,-1,8,3,4,3,99],   &[9], &[0]);
     run_example(vec![3,21,1008,21,8,20,1005,20,22,107,8,21,20,1006,20,31,
                      1106,0,36,98,0,0,1002,21,125,20,4,20,1105,1,46,104,
                      999,1105,1,46,1101,1000,1,20,4,20,1105,1,46,98,99],
-                vec![3], vec![999]);
+                &[3], &[999]);
     run_example(vec![3,21,1008,21,8,20,1005,20,22,107,8,21,20,1006,20,31,
                      1106,0,36,98,0,0,1002,21,125,20,4,20,1105,1,46,104,
                      999,1105,1,46,1101,1000,1,20,4,20,1105,1,46,98,99],
-                vec![8], vec![1000]);
+                &[8], &[1000]);
     run_example(vec![3,21,1008,21,8,20,1005,20,22,107,8,21,20,1006,20,31,
                      1106,0,36,98,0,0,1002,21,125,20,4,20,1105,1,46,104,
                      999,1105,1,46,1101,1000,1,20,4,20,1105,1,46,98,99],
-                vec![192], vec![1001]);
+                &[192], &[1001]);
 
     let example7a = Computer::from_string("3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0");
     let result7a = example7a.serialize(vec![4,3,2,1,0]);
@@ -416,15 +478,15 @@ fn test_examples() {
     assert_eq!(vec![9,7,8,5,6], example7ft);
 
     run_example(vec![109,1,204,-1,1001,100,1,100,1008,100,16,101,1006,101,0,99],
-                vec![],
-                vec![109,1,204,-1,1001,100,1,100,1008,100,16,101,1006,101,0,99]);
+                &[],
+                &[109,1,204,-1,1001,100,1,100,1008,100,16,101,1006,101,0,99]);
     run_example(vec![1102,34915192,34915192,7,4,7,99,0],
-                vec![],
-                vec![1219070632396864]);
+                &[],
+                &[1219070632396864]);
     run_example(vec![104,1125899906842624,99],
-                vec![],
-                vec![1125899906842624]);
+                &[],
+                &[1125899906842624]);
 
-    run_computer(Computer::load("inputs/day9"), vec![1], vec![3063082071]);
-    run_computer(Computer::load("inputs/day9"), vec![2], vec![81348]);
+    run_computer(Computer::load("inputs/day9"), &[1], &[3063082071]);
+    run_computer(Computer::load("inputs/day9"), &[2], &[81348]);
 }

src/main.rs

@@ -1,17 +1,16 @@
 mod arcade;
 mod args;
-mod endchannel;
 mod fuel;
 mod image;
 mod machine;
 mod orbits;
+#[cfg(test)]
 mod repair;
+#[cfg(test)]
 mod robot;
 mod wiremap;
 
-use crate::arcade::{auto_move, Move};
 use crate::args::Command;
-use crate::endchannel::channel;
 use crate::fuel::calculate_fuel;
 use crate::orbits::Object;
 use crate::wiremap::WireMap;
@@ -32,15 +31,12 @@ fn main() {
             println!("TOTAL FUEL: {}", total);
         }
 
-        Command::RunComputer(mut initial) => {
-            let (my_sender,    mut their_receiver) = channel();
-            let (mut their_sender, my_receiver)    = channel();
+        Command::RunComputer(initial) => {
             println!("Initial Computer:");
             initial.show();
             println!("Running, with input 5.");
-            my_sender.send(5);
-            initial.run(&mut their_receiver, &mut their_sender);
-            for val in my_receiver {
+            let results = initial.standard_run(&[5]);
+            for val in results.iter() {
                 println!("Received value: {}", val);
             }
         }
@@ -162,15 +158,15 @@ fn main() {
             image.draw();
         }
 
-        Command::Arcade(mut arcade) => {
+        Command::Arcade(arcade) => {
             let mut screen = Display::new(40, 40);
 
             screen.clear();
-            while arcade.process_update(auto_move) {
-                arcade.draw(&mut screen);
+            let result = arcade.run(move |a| {
+                a.draw(&mut screen);
                 screen.print();
-            }
-            println!("Final score: {}", arcade.score);
+            });
+            println!("Final score: {}", result.score);
         }
     }
  }

src/repair.rs

@@ -1,7 +1,5 @@
-use crate::endchannel::{Receiver, Sender, channel};
-use crate::machine::Computer;
+use crate::machine::{Computer, RunResult};
 use std::collections::VecDeque;
-use std::thread;
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 enum Direction {
@@ -20,16 +18,6 @@ impl Direction {
             Direction::West  => (x - 1, y),
         }
     }
-
-    fn random() -> Direction {
-        match rand::random::<u8>() & 0x3 {
-            0 => Direction::North,
-            1 => Direction::East,
-            2 => Direction::South,
-            3 => Direction::West,
-            _ => panic!("The world broke")
-        }
-    }
 }
 
 const ALL_DIRECTIONS: [Direction; 4] = [Direction::North,
@@ -38,15 +26,6 @@ const ALL_DIRECTIONS: [Direction; 4] = [Direction::North,
                                         Direction::West];
 
 impl Direction {
-    fn reverse(&self) -> Direction {
-        match self {
-            Direction::North => Direction::South,
-            Direction::East  => Direction::West,
-            Direction::South => Direction::North,
-            Direction::West  => Direction::East,
-        }
-    }
-
     fn encode(&self) -> i64 {
         match self {
             Direction::North => 1,
@@ -67,16 +46,6 @@ impl Path {
         Path{ steps: vec![] }
     }
 
-    fn reverse(&self) -> Path {
-        let mut steps = Vec::with_capacity(self.steps.len());
-
-        for step in self.steps.iter().rev() {
-            steps.push(step.reverse());
-        }
-
-        Path{ steps }
-    }
-
     fn extend(&self) -> Vec<Path> {
         let mut res = Vec::with_capacity(4);
 
@@ -145,29 +114,33 @@ impl RepairSearch {
     }
 
     fn try_path(&mut self, path: &Path) -> MoveResult {
-        let (mut mysend, mut corecv) = channel();
-        let (mut cosend, mut myrecv) = channel();
-        let my_computer = self.computer.clone();
+        let mut my_computer = self.computer.clone();
         let mut last_response = MoveResult::Done;
+        let mut idx = 0;
 
-        thread::spawn(move || my_computer.clone().run(&mut corecv, &mut cosend));
-        for step in path.steps.iter() {
-            mysend.send(step.encode());
-            match myrecv.recv() {
-                None =>
+        loop {
+            match my_computer.run() {
+                RunResult::Continue(next) =>
+                    my_computer = next,
+                RunResult::Halted(_) =>
                     return last_response,
-                Some(response) => {
-                    last_response = MoveResult::new(response);
+                RunResult::Output(x, next) => {
+                    my_computer = next;
+                    last_response = MoveResult::new(x);
                     if last_response == MoveResult::HitWall {
-                        break
+                        return last_response;
+                    }
+                }
+                RunResult::Input(c)  => {
+                    if idx >= path.steps.len() {
+                        return last_response;
+                    }
+                    my_computer = c(path.steps[idx].encode());
+                    idx += 1;
                 }
             }
         }
     }
-        mysend.conclude();
-
-        last_response
-    }
 
     fn run_search(&mut self) -> usize {
         let mut horizon = Path::new().extend();
@@ -201,8 +174,7 @@ enum Tile {
 
 struct Room {
     layout: Vec<Tile>,
-    computer_input: Sender<i64>,
-    computer_output: Receiver<i64>,
+    computer: Computer,
     width: usize,
     height: usize,
     x: usize,
@@ -211,17 +183,13 @@ struct Room {
 
 impl Room {
     fn new(width: usize, height: usize, f: &str) -> Room {
-        let (mut mysend, mut corecv) = channel();
-        let (mut cosend, mut myrecv) = channel();
-        let mut my_computer = Computer::load(f);
+        let computer = Computer::load(f);
         let mut layout = Vec::with_capacity(width * height);
 
         layout.resize(width * height, Tile::Unknown);
-        thread::spawn(move || my_computer.run(&mut corecv, &mut cosend));
         Room{
             layout,
-            computer_input: mysend,
-            computer_output: myrecv,
+            computer,
             width, height,
             x: width / 2,
             y: height / 2,
@@ -248,6 +216,7 @@ impl Room {
         res
     }
 
+    /*
     fn print(&self) {
         println!("\n\n\n\n\n\n");
         for y in 0..self.height {
@@ -266,6 +235,7 @@ impl Room {
             println!();
         }
     }
+    */
 
     fn next_unknown(&self) -> Option<Direction> {
         let mut visited = vec![];
@@ -292,51 +262,61 @@ impl Room {
         None
     }
 
-    fn step(&mut self, direction: Direction) -> bool {
+    fn step(mut self, direction: Direction) -> (Self, bool) {
         let (tx, ty) = direction.apply(self.x, self.y);
 
         if self.get(tx, ty) == Tile::Wall {
-            return false;
+            return (self, false);
         }
 
-        self.computer_input.send(direction.encode());
-        match self.computer_output.recv() {
-            None => false,
-            Some(resp) => {
+        loop {
+            match self.computer.run() {
+                RunResult::Continue(next) =>
+                    self.computer = next,
+                RunResult::Halted(next) => {
+                    self.computer = next;
+                    return (self, false);
+                }
+                RunResult::Input(c) =>
+                    self.computer = c(direction.encode()),
+                RunResult::Output(resp, next) => {
                     let response = MoveResult::new(resp);
 
+                    self.computer = next;
                     match response {
                         MoveResult::HitWall => {
                             self.set(tx, ty, Tile::Wall);
-                        false
+                            return (self, false);
                         }
                         MoveResult::Done => {
                             self.set(tx, ty, Tile::Empty);
                             self.x = tx;
                             self.y = ty;
-                        true
+                            return (self, true);
                         }
                         MoveResult::FoundSystem => {
                             self.set(tx, ty, Tile::Oxygen);
                             self.x = tx;
                             self.y = ty;
-                        true
+                            return (self, true);
+                        }
                     }
                 }
             }
         }
     }
 
-    fn map_room(&mut self) -> usize {
+    fn map_room(mut self) -> (Self, usize) {
         let mut steps = 0;
 
         while let Some(next_step) = self.next_unknown() {
             //println!("Steps taken: {} [x {}, y {}, next {:?}]", steps, self.x, self.y, next_step);
-            self.step(next_step);
+            let (next, _) = self.step(next_step);
+            self = next;
             steps += 1;
         }
 
-        steps
+        (self, steps)
     }
 
     fn has_empty_space(&self) -> bool {
@@ -381,8 +361,9 @@ fn day15a() {
 
 #[test]
 fn day15b() {
-    let mut day15b = Room::new(50, 50, "inputs/day15");
+    let day15b = Room::new(50, 50, "inputs/day15");
     assert!(day15b.next_unknown().is_some());
-    assert_eq!(2452, day15b.map_room());
-    assert_eq!(346, day15b.spread());
+    let (mut mapped, size) = day15b.map_room();
+    assert_eq!(2452, size);
+    assert_eq!(346, mapped.spread());
 }

src/robot.rs

@@ -1,33 +1,26 @@
-use crate::endchannel::{Sender, Receiver, channel};
-use crate::machine::Computer;
+use crate::machine::{Computer, RunResult};
 use image::{ImageBuffer, Rgb};
-use std::thread;
 
 struct HullGrid {
     data: ImageBuffer<Rgb<u8>, Vec<u8>>,
+    computer: Computer,
     robot_x: u32,
     robot_y: u32,
     robot_dir: Direction,
-    sender: Sender<i64>,
-    receiver: Receiver<i64>,
 }
 
 impl HullGrid {
     fn new(width: u32, height: u32, computer_path: &str) -> HullGrid {
-        let mut init_computer = Computer::load(computer_path);
-        let (    mysend, mut corecv) = channel();
-        let (mut cosend,     myrecv) = channel();
+        let computer = Computer::load(computer_path);
 
         assert!(width & 1 == 1);
         assert!(height & 1 == 1);
-        thread::spawn(move || init_computer.run(&mut corecv, &mut cosend));
         HullGrid {
             data: ImageBuffer::new(width, height),
+            computer,
             robot_x: width / 2,
             robot_y: height / 2,
             robot_dir: Direction::Up,
-            sender: mysend,
-            receiver: myrecv,
         }
     }
 
@@ -53,29 +46,55 @@ impl HullGrid {
         }
     }
 
-    fn paint_next(&mut self) -> bool {
-        self.sender.send_ignore_error(if self.is_white() { 1 } else { 0 });
-        match self.receiver.recv() {
-            None =>
-                false,
-            Some(new_color) => {
-                let rotation = self.receiver.recv().expect("Didn't get rotation back");
-                if new_color == 0 { self.set_black() } else { self.set_white() }
+    fn paint_next(mut self, output: Option<&str>) -> Option<Self> {
+        let mut new_color: Option<i64> = None;
+
+        loop {
+            let color = if self.is_white() { 1 } else { 0 };
+
+            match self.computer.run() {
+                RunResult::Continue(next) =>
+                    self.computer = next,
+                RunResult::Halted(next) => {
+                    self.computer = next;
+                    if let Some(fname) = output {
+                        self.render(fname);
+                    }
+                    return None;
+                }
+                RunResult::Input(c) =>
+                    self.computer = c(color),
+                RunResult::Output(o, next) if new_color.is_none() => {
+                    new_color = Some(o);
+                    self.computer = next;
+                }
+                RunResult::Output(rotation, next) => {
+                    self.computer = next;
+
+                    if new_color.unwrap() == 0 {
+                        self.set_black()
+                    } else {
+                        self.set_white()
+                    }
+
                     self.robot_dir = if rotation == 0 {
                         self.robot_dir.rotate_right()
                     } else {
                         self.robot_dir.rotate_left()
                     };
+
                     self.step();
-                true
+                    return Some(self);
+                }
             }
         }
     }
 
-    fn paint_hull(&mut self) -> usize {
+    fn paint_hull(mut self, output: Option<&str>) -> usize {
         let mut points = vec![];
 
-        while self.paint_next() {
+        while let Some(next) = self.paint_next(output) {
+            self = next;
             let cur = (self.robot_x, self.robot_y);
             if !points.contains(&cur) {
                 points.push(cur);
@@ -86,7 +105,12 @@ impl HullGrid {
     }
 
     fn render(&self, file: &str) {
-        self.data.save(file);
+        match self.data.save(file) {
+            Err(e) =>
+                println!("Error saving file: {}", e),
+            Ok(_) =>
+                {}
+        }
     }
 }
 
@@ -143,10 +167,9 @@ fn rotations_work() {
 
 #[test]
 fn day11() {
-    let mut day1a = HullGrid::new(1001, 1001, "inputs/day11");
-    assert_eq!(2373, day1a.paint_hull());
+    let day1a = HullGrid::new(1001, 1001, "inputs/day11");
+    assert_eq!(2373, day1a.paint_hull(None));
     let mut day1b = HullGrid::new(1001, 1001, "inputs/day11");
     day1b.set_white();
-    assert_eq!(249, day1b.paint_hull());
-    day1b.render("day1.png");
+    assert_eq!(249, day1b.paint_hull(None));
 }