refactor to have a world run a process

sandbox.ld

@@ -1,4 +1 @@
-repeat 1 {
+:foobar
- fd! (100)
- rt! (0.25)
-}

src/lib.rs

@@ -8,7 +8,9 @@ const DEBUG_PRELUDE_COMPILE: bool = false;
 const DEBUG_PRELUDE_RUN: bool = false;
 
 mod base;
+
 mod world;
+use crate::world::World;
 
 mod spans;
 use crate::spans::Spanned;
@@ -144,8 +146,11 @@ pub fn ludus(src: String) -> String {
 
     let vm_chunk = compiler.chunk;
 
-    let mut vm = Creature::new(vm_chunk, DEBUG_SCRIPT_RUN);
+    let vm = Creature::new(vm_chunk, DEBUG_SCRIPT_RUN);
-    let result = vm.run();
+    let grip = World::new(vm);
+    grip.borrow_mut().run();
+    let world = grip.borrow();
+    let result = world.result.clone().unwrap();
 
     let console = postlude.get("console").unwrap();
     let Value::Box(console) = console else {
@@ -165,7 +170,6 @@ pub fn ludus(src: String) -> String {
         unreachable!()
     };
     let commands = commands.borrow();
-    dbg!(&commands);
     let commands = commands.to_json().unwrap();
 
     let output = match result {
@@ -176,7 +180,7 @@ pub fn ludus(src: String) -> String {
         }
     };
     if DEBUG_SCRIPT_RUN {
-        vm.print_stack();
+        // vm.print_stack();
     }
 
     // TODO: use serde_json to make this more robust?

src/vm.rs

@@ -4,13 +4,17 @@ use crate::op::Op;
 use crate::parser::Ast;
 use crate::spans::Spanned;
 use crate::value::{LFn, Value};
+use crate::world::Grasp;
 use imbl::{HashMap, Vector};
 use num_traits::FromPrimitive;
 use std::cell::RefCell;
+use std::collections::VecDeque;
 use std::fmt;
 use std::mem::swap;
 use std::rc::Rc;
 
+const MAX_REDUCTIONS: usize = 100;
+
 #[derive(Debug, Clone, PartialEq)]
 pub enum Panic {
     Str(&'static str),
@@ -86,6 +90,9 @@ pub struct Creature {
     debug: bool,
     last_code: usize,
     pub id: &'static str,
+    pub world: Grasp,
+    pub mbx: VecDeque<Value>,
+    pub reductions: usize,
 }
 
 impl Creature {
@@ -117,9 +124,20 @@ impl Creature {
             debug,
             last_code: 0,
             id: "",
+            world: None,
+            mbx: VecDeque::new(),
+            reductions: 0,
         }
     }
 
+    pub fn reduce(&mut self) {
+        self.reductions += 1;
+    }
+
+    pub fn receive(&mut self, value: Value) {
+        self.mbx.push_back(value);
+    }
+
     pub fn chunk(&self) -> &Chunk {
         self.frame.chunk()
     }
@@ -225,6 +243,9 @@ impl Creature {
                 self.result = Some(Ok(self.stack.pop().unwrap()));
                 return;
             }
+            if self.reductions >= MAX_REDUCTIONS {
+                return;
+            }
             let code = self.read();
             if self.debug {
                 self.last_code = self.ip - 1;

src/world.rs

@@ -1,10 +1,11 @@
 use crate::value::Value;
 use crate::vm::{Creature, Panic};
 use ran::ran_u8;
-use std::collections::{HashMap, VecDeque};
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::rc::Rc;
 
 const ANIMALS: [&str; 24] = [
-    "turtle",
     "tortoise",
     "hare",
     "squirrel",
@@ -28,6 +29,7 @@ const ANIMALS: [&str; 24] = [
     "giraffe",
     "leopard",
     "lion",
+    "hippopotamus",
 ];
 
 #[derive(Debug, Clone, PartialEq)]
@@ -43,6 +45,7 @@ struct Zoo {
     empty: Vec<usize>,
     ids: HashMap<&'static str, usize>,
     dead: Vec<&'static str>,
+    active: usize,
 }
 
 impl Zoo {
@@ -52,14 +55,28 @@ impl Zoo {
             empty: vec![],
             ids: HashMap::new(),
             dead: vec![],
+            active: 0,
         }
     }
 
+    fn random_id(&self) -> String {
+        let rand = ran_u8() as usize % 24;
+        let idx = self.procs.len();
+        format!("{}_{idx}", ANIMALS[rand])
+    }
+
+    fn new_id(&self) -> &'static str {
+        let mut new = self.random_id();
+        while self.dead.iter().any(|old| *old == new) {
+            new = self.random_id();
+        }
+        new.leak()
+    }
+
     pub fn put(&mut self, mut proc: Creature) -> &'static str {
         if self.empty.is_empty() {
-            let rand = ran_u8() as usize % 24;
+            let id = self.new_id();
             let idx = self.procs.len();
-            let id = format!("{}_{idx}", ANIMALS[rand]).leak();
             proc.id = id;
             self.procs.push(Status::Nested(proc));
             self.ids.insert(id, idx);
@@ -106,76 +123,136 @@ impl Zoo {
             unreachable!("tried to return a process the world doesn't know about");
         }
     }
+
+    pub fn next(&mut self, curr_id: &'static str) -> &'static str {
+        let idx = self.ids.get(curr_id).unwrap();
+        if *idx != self.active {
+            panic!(
+                "tried to get next creature after {curr_id} while {} is active",
+                self.active
+            );
+        }
+        self.active = (self.active + 1) % self.procs.len();
+        while self.procs[self.active] != Status::Empty {
+            self.active = (self.active + 1) % self.procs.len();
+        }
+        match &self.procs[self.active] {
+            Status::Empty => unreachable!(),
+            Status::Borrowed => panic!(
+                "encountered unexpectedly borrowed process at idx {}",
+                self.active
+            ),
+            Status::Nested(proc) => proc.id,
+        }
+    }
 }
 
+pub type Grasp = Option<Rc<RefCell<World>>>;
+
+#[derive(Debug, Clone, PartialEq)]
 pub struct World {
-    procs: Zoo,
+    zoo: Zoo,
-    mbxes: HashMap<String, VecDeque<Value>>,
+    active: Option<Creature>,
-    active: Creature,
-    // TODO: we need a lifetime here
     main: &'static str,
+    handle: Grasp,
+    pub result: Option<Result<Value, Panic>>,
 }
 
 impl World {
-    pub fn new(proc: Creature) -> World {
+    pub fn new(proc: Creature) -> Rc<RefCell<World>> {
-        let mut creatures = Zoo::new();
+        let mut zoo = Zoo::new();
-        let id = creatures.put(proc);
+        let id = zoo.put(proc);
-        let caught = creatures.catch(id);
+        let world = World {
-        World {
+            zoo,
-            procs: creatures,
+            active: None,
-            mbxes: HashMap::new(),
-            active: caught,
             main: id,
-        }
+            handle: None,
+            result: None,
+        };
+        let handle = Rc::new(RefCell::new(world));
+        let grasped = handle.clone();
+        let mut world = grasped.as_ref().borrow_mut();
+        world.handle = Some(grasped.clone());
+
+        let mut caught = world.zoo.catch(id);
+        caught.world = world.handle.clone();
+        world.zoo.release(caught);
+
+        handle
     }
 
     pub fn spawn(&mut self, proc: Creature) -> Value {
-        let id = self.procs.put(proc);
+        let id = self.zoo.put(proc);
         Value::Keyword(id)
     }
 
     pub fn send_msg(&mut self, id: &'static str, msg: Value) {
-        let mbx = self.mbxes.get_mut(id).unwrap();
+        let mut proc = self.zoo.catch(id);
-        mbx.push_back(msg);
+        proc.receive(msg);
+        self.zoo.release(proc);
     }
 
-    pub fn sleep(&mut self, id: &'static str) {
+    fn next(&mut self) {
-        // check if the id is the actually active process
+        let id = self.zoo.next(self.active.as_ref().unwrap().id);
-        // return it to the nursery
+        let mut active = None;
-        // get the next process from the nursery
+        std::mem::swap(&mut active, &mut self.active);
+        let mut holding_pen = self.zoo.catch(id);
+        let mut active = active.unwrap();
+        std::mem::swap(&mut active, &mut holding_pen);
+        self.zoo.release(holding_pen);
+        let mut active = Some(active);
+        std::mem::swap(&mut active, &mut self.active);
     }
 
-    pub fn get_msg(&self, id: &'static str) -> Option<(usize, Value)> {
+    // pub fn sleep(&mut self, id: &'static str) {
-        // check if the id is of the active process
+    //     // check if the id is the actually active process
-        todo!()
+    //     if self.active.id != id {
-    }
+    //         panic!("attempted to sleep a process from outside that process: active = {}; to sleep: = {id}", self.active.id);
+    //     }
+    //     self.next(id);
+    // }
 
-    pub fn match_msg(&mut self, id: &'static str, idx: usize) {
+    // pub fn panic(&mut self, id: &'static str, panic: Panic) {
-        // again, check for activity
+    //     // TODO: devise some way of linking processes (study the BEAM on this)
-        // delete the message at idx, which we gave along with the value as the tuple in get_msg
+    //     // check if the id is active
-    }
+    //     if self.active.id != id {
+    //         panic!("attempted to panic from a process from outside that process: active = {}; panicking = {id}; panic = {panic}", self.active.id);
+    //     }
+    //     // check if the process is `main`, and crash the program if it is
+    //     if self.main == id {
+    //         self.result = self.active.result.clone();
+    //     }
+    //     // kill the process
+    //     self.zoo.kill(id);
+    //     self.next(id);
+    // }
 
-    pub fn r#yield(&mut self, id: &'static str) {
+    // pub fn complete(&mut self) {
-        // check if the id is active
+    //     if self.main == self.active.id {
-        // swap out the currently active process for the next one
+    //         self.result = self.active.result.clone();
-    }
+    //     }
+    //     self.next(id);
+    // }
 
-    pub fn panic(&mut self, id: &'static str) {
+    pub fn run(&mut self) {
-        // TODO: devise some way of linking processes (study the BEAM on this)
+        loop {
-        // check if the id is active
+            if self.active.is_none() {
-        // check if the process is `main`, and crash the program if it is
+                let main = self.zoo.catch(self.main);
-        // kill the process
+                self.active = Some(main);
-        // swap out this process for the next one
             }
-
+            self.active.as_mut().unwrap().interpret();
-    pub fn complete(&mut self, id: &'static str, value: Value) {
+            match self.active.as_ref().unwrap().result {
-        // check if the id is active
+                None => (),
-        // check if the process is main
+                Some(_) => {
-        // if it is: stash the value somehow and exit the program cleanly
+                    if self.active.as_ref().unwrap().id == self.main {
+                        self.result = self.active.as_ref().unwrap().result.clone();
+                        return;
+                    }
+                    self.zoo.kill(self.active.as_ref().unwrap().id);
+                }
+            }
+            self.next();
         }
-
-    pub fn run(&mut self) -> Result<Value, Panic> {
-        todo!()
     }
 
     // TODO: