start work on actor model

src/lib.rs

@@ -8,6 +8,7 @@ const DEBUG_PRELUDE_COMPILE: bool = false;
 const DEBUG_PRELUDE_RUN: bool = false;
 
 mod base;
+mod world;
 
 mod spans;
 use crate::spans::Spanned;
@@ -34,7 +35,7 @@ mod value;
 use value::Value;
 
 mod vm;
-use vm::Vm;
+use vm::Creature;
 
 const PRELUDE: &str = include_str!("../assets/test_prelude.ld");
 
@@ -81,7 +82,7 @@ fn prelude() -> HashMap<&'static str, Value> {
     compiler.compile();
 
     let chunk = compiler.chunk;
-    let mut vm = Vm::new(chunk, DEBUG_PRELUDE_RUN);
+    let mut vm = Creature::new(chunk, DEBUG_PRELUDE_RUN);
     let prelude = vm.run().clone().unwrap();
     match prelude {
         Value::Dict(hashmap) => *hashmap,
@@ -143,7 +144,7 @@ pub fn ludus(src: String) -> String {
 
     let vm_chunk = compiler.chunk;
 
-    let mut vm = Vm::new(vm_chunk, DEBUG_SCRIPT_RUN);
+    let mut vm = Creature::new(vm_chunk, DEBUG_SCRIPT_RUN);
     let result = vm.run();
 
     let console = postlude.get("console").unwrap();

src/vm.rs

@@ -12,14 +12,6 @@ use std::mem::swap;
 use std::rc::Rc;
 
 #[derive(Debug, Clone, PartialEq)]
-// pub struct Panic {
-//     pub input: &'static str,
-//     pub src: &'static str,
-//     pub msg: String,
-//     pub span: SimpleSpan,
-//     pub trace: Vec<Trace>,
-//     pub extra: String,
-// }
 pub enum Panic {
     Str(&'static str),
     String(String),
@@ -44,6 +36,7 @@ pub struct Trace {
     pub src: &'static str,
 }
 
+#[derive(Debug, Clone, PartialEq)]
 pub struct CallFrame {
     pub function: Value,
     pub arity: u8,
@@ -80,7 +73,8 @@ fn combine_bytes(high: u8, low: u8) -> usize {
     out as usize
 }
 
-pub struct Vm {
+#[derive(Debug, Clone, PartialEq)]
+pub struct Creature {
     pub stack: Vec<Value>,
     pub call_stack: Vec<CallFrame>,
     pub frame: CallFrame,
@@ -91,10 +85,11 @@ pub struct Vm {
     pub result: Option<Result<Value, Panic>>,
     debug: bool,
     last_code: usize,
+    pub id: &'static str,
 }
 
-impl Vm {
-    pub fn new(chunk: Chunk, debug: bool) -> Vm {
+impl Creature {
+    pub fn new(chunk: Chunk, debug: bool) -> Creature {
         let lfn = LFn::Defined {
             name: "user script",
             doc: None,
@@ -110,7 +105,7 @@ impl Vm {
             ip: 0,
             arity: 0,
         };
-        Vm {
+        Creature {
             stack: vec![],
             call_stack: Vec::with_capacity(64),
             frame: base_frame,
@@ -121,6 +116,7 @@ impl Vm {
             result: None,
             debug,
             last_code: 0,
+            id: "",
         }
     }
 

src/world.rs

@@ -0,0 +1,205 @@
+use crate::value::Value;
+use crate::vm::{Creature, Panic};
+use ran::ran_u8;
+use std::collections::{HashMap, VecDeque};
+
+const ANIMALS: [&str; 24] = [
+    "turtle",
+    "tortoise",
+    "hare",
+    "squirrel",
+    "hawk",
+    "woodpecker",
+    "cardinal",
+    "coyote",
+    "raccoon",
+    "rat",
+    "axolotl",
+    "cormorant",
+    "duck",
+    "orca",
+    "humbpack",
+    "tern",
+    "quokka",
+    "koala",
+    "kangaroo",
+    "zebra",
+    "hyena",
+    "giraffe",
+    "leopard",
+    "lion",
+];
+
+#[derive(Debug, Clone, PartialEq)]
+enum Status {
+    Empty,
+    Borrowed,
+    Nested(Creature),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+struct Zoo {
+    procs: Vec<Status>,
+    empty: Vec<usize>,
+    ids: HashMap<&'static str, usize>,
+    dead: Vec<&'static str>,
+}
+
+impl Zoo {
+    pub fn new() -> Zoo {
+        Zoo {
+            procs: vec![],
+            empty: vec![],
+            ids: HashMap::new(),
+            dead: vec![],
+        }
+    }
+
+    pub fn put(&mut self, mut proc: Creature) -> &'static str {
+        if self.empty.is_empty() {
+            let rand = ran_u8() as usize % 24;
+            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);
+            id
+        } else {
+            let idx = self.empty.pop().unwrap();
+            let rand = ran_u8() as usize % 24;
+            let id = format!("{}_{idx}", ANIMALS[rand]).leak();
+            proc.id = id;
+            self.ids.insert(id, idx);
+            self.procs[idx] = Status::Nested(proc);
+            id
+        }
+    }
+
+    pub fn kill(&mut self, id: &'static str) {
+        if let Some(idx) = self.ids.get(id) {
+            self.procs[*idx] = Status::Empty;
+            self.empty.push(*idx);
+            self.ids.remove(&id);
+            self.dead.push(id);
+        }
+    }
+
+    pub fn catch(&mut self, id: &'static str) -> Creature {
+        if let Some(idx) = self.ids.get(id) {
+            let mut proc = Status::Borrowed;
+            std::mem::swap(&mut proc, &mut self.procs[*idx]);
+            let Status::Nested(proc) = proc else {
+                unreachable!("tried to borrow an empty or already-borrowed process");
+            };
+            proc
+        } else {
+            unreachable!("tried to borrow a non-existent process");
+        }
+    }
+
+    pub fn release(&mut self, proc: Creature) {
+        let id = proc.id;
+        if let Some(idx) = self.ids.get(id) {
+            let mut proc = Status::Nested(proc);
+            std::mem::swap(&mut proc, &mut self.procs[*idx]);
+        } else {
+            unreachable!("tried to return a process the world doesn't know about");
+        }
+    }
+}
+
+pub struct World {
+    procs: Zoo,
+    mbxes: HashMap<String, VecDeque<Value>>,
+    active: Creature,
+    // TODO: we need a lifetime here
+    main: &'static str,
+}
+
+impl World {
+    pub fn new(proc: Creature) -> World {
+        let mut creatures = Zoo::new();
+        let id = creatures.put(proc);
+        let caught = creatures.catch(id);
+        World {
+            procs: creatures,
+            mbxes: HashMap::new(),
+            active: caught,
+            main: id,
+        }
+    }
+
+    pub fn spawn(&mut self, proc: Creature) -> Value {
+        let id = self.procs.put(proc);
+        Value::Keyword(id)
+    }
+
+    pub fn send_msg(&mut self, id: &'static str, msg: Value) {
+        let mbx = self.mbxes.get_mut(id).unwrap();
+        mbx.push_back(msg);
+    }
+
+    pub fn sleep(&mut self, id: &'static str) {
+        // check if the id is the actually active process
+        // return it to the nursery
+        // get the next process from the nursery
+    }
+
+    pub fn get_msg(&self, id: &'static str) -> Option<(usize, Value)> {
+        // check if the id is of the active process
+        todo!()
+    }
+
+    pub fn match_msg(&mut self, id: &'static str, idx: usize) {
+        // again, check for activity
+        // delete the message at idx, which we gave along with the value as the tuple in get_msg
+    }
+
+    pub fn r#yield(&mut self, id: &'static str) {
+        // check if the id is active
+        // swap out the currently active process for the next one
+    }
+
+    pub fn panic(&mut self, id: &'static str) {
+        // TODO: devise some way of linking processes (study the BEAM on this)
+        // check if the id is active
+        // check if the process is `main`, and crash the program if it is
+        // kill the process
+        // swap out this process for the next one
+    }
+
+    pub fn complete(&mut self, id: &'static str, value: Value) {
+        // check if the id is active
+        // check if the process is main
+        // if it is: stash the value somehow and exit the program cleanly
+    }
+
+    pub fn run(&mut self) -> Result<Value, Panic> {
+        todo!()
+    }
+
+    // TODO:
+    // * [ ] Maybe I need to write this from the bottom up?
+    //   What do processes need to do?
+    //   - [ ] send a message to another process
+    //   - [ ] tell the world to spawn a new process, get the pid back
+    //   - [ ] receive its messages (always until something matches, or sleep if nothing matches)
+    //   - [ ] delete a message from the mbx if it's a match (by idx)
+    //   - [ ] yield
+    //   - [ ] panic
+    //   - [ ] complete
+    //  Thus the other side of this looks like:
+    //  * [x] Spawn a process
+    //  * [x]
+}
+
+// Okay, some more thinking
+// The world and process can't have mutable references to one another
+// They will each need an Rc<RefCell<PostOffice>>
+// All the message passing and world/proc communication will happen through there
+// And ownership goes World -> Process A -> World -> Process B
+
+// Both the world and a process will have an endless `loop`.
+// But I already have three terms: Zoo, Creature, and World
+// That should be enough indirection?
+// To solve tomorrow.