middleware should now handle multiple turtles

may_2025_thoughts.md

@@ -1233,9 +1233,21 @@ Anyway, here's the tl;dr for basic process linking:
 * `monitor/1` means we can monitor exit messages, these will be `(:exit, pid, (:ok, value))` in the case of successful return, or `(:exit, pid, (:err, msg))` in the case of a panic. These are sent as normal messages to the monitoring process.
 
 Erlang/Elixir has a lot more, but that's basically it for Ludus for now.
+I don't think we need more than the binary: `:ok`/`:err`, or return/panic as how processes exit.
 `monitor/1` makes it easy to write an `await`.
+We would need a way of killing processes remotely if indeed we wanted to write robust distributed applications.
+But I'm less interested in that than in the cognitive modelling here.
 
 As I'm thinking about this, I actually want to roll back `spawn` as a special form.
 I think it's actually a good cognitive shift to understand that functions are reified, deferred computations.
 And that processes take this a long way.
 We can revisit the idea of a special spawn form later.
+
+=> done
+
+And now, we build capacity for building projects.
+
+* [ ] allow for multiple turtles
+    - [ ] rework p5 function in `ludus.js` to properly parse commands targeted at different turtles
+    - [ ] write ludus code to spawn & manipulate turtle actors
+* [ ] do some sample multiturtle sketches

pkg/ludus.js

@@ -1,4 +1,4 @@
-if (window) window.ludus = {run, kill, flush_stdout, stdout, p5, svg, flush_commands, commands, result, flush_result, input, is_running, key_down, key_up, is_starting_up}
+if (window) window.ludus = {run, kill, flush_stdout, stdout, p5, new_p5, svg, flush_commands, commands, result, flush_result, input, is_running, key_down, key_up, is_starting_up}
 
 const worker_url = new URL("worker.js", import.meta.url)
 const worker = new Worker(worker_url, {type: "module"})
@@ -51,7 +51,7 @@ async function handle_messages (e) {
       case "Commands": {
         console.log("Main: ludus commands => ", msg.data)
         for (const command of msg.data) {
-          // attempt to solve out-of-order command bug
+          // commands will arrive asynchronously; ensure correct ordering
           ludus_commands[command[1]] = command
         }
         break
@@ -236,69 +236,71 @@ function unit_of (heading) {
   return [Math.cos(radians), Math.sin(radians)]
 }
 
-function command_to_state (prev_state, command) {
-  const [_target, _id, curr_command] = command
+function command_to_state (state, command) {
+  const [target, _id, curr_command] = command
+  const state_stack = state[target] ?? [turtle_init]
+  const prev_state = state_stack[state_stack.length - 1]
   const [verb] = curr_command
   switch (verb) {
     case "goto": {
       const [_, x, y] = curr_command
-      return {...prev_state, position: [x, y]}
+      return [target, {...prev_state, position: [x, y]}]
     }
     case "home": {
-      return {...prev_state, position: [0, 0], heading: 0}
+      return [target, {...prev_state, position: [0, 0], heading: 0}]
     }
     case "right": {
       const [_, angle] = curr_command
       const {heading} = prev_state
-      return {...prev_state, heading: heading + angle}
+      return [target, {...prev_state, heading: heading + angle}]
     }
     case "left": {
       const [_, angle] = curr_command
       const {heading} = prev_state
-      return {...prev_state, heading: heading - angle}
+      return [target, {...prev_state, heading: heading - angle}]
     }
     case "forward": {
       const [_, steps] = curr_command
       const {heading, position} = prev_state
       const unit = unit_of(heading)
       const move = mult(unit, steps)
-      return {...prev_state, position: add(position, move)}
+      return [target, {...prev_state, position: add(position, move)}]
     }
     case "back": {
       const [_, steps] = curr_command
       const {heading, position} = prev_state
       const unit = unit_of(heading)
       const move = mult(unit, -steps)
-      return {...prev_state, position: add(position, move)}
+      return [target, {...prev_state, position: add(position, move)}]
     }
     case "penup": {
-      return {...prev_state, pendown: false}
+      return [target, {...prev_state, pendown: false}]
     }
     case "pendown": {
-      return {...prev_state, pendown: true}
+      return [target, {...prev_state, pendown: true}]
     }
     case "penwidth": {
       const [_, width] = curr_command
-      return {...prev_state, penwidth: width}
+      return [target, {...prev_state, penwidth: width}]
     }
     case "pencolor": {
       const [_, color] = curr_command
-      return {...prev_state, pencolor: color}
+      return [target, {...prev_state, pencolor: color}]
     }
     case "setheading": {
       const [_, heading] = curr_command
-      return {...prev_state, heading: heading}
+      return [target, {...prev_state, heading: heading}]
     }
     case "loadstate": {
       // console.log("LOADSTATE: ", curr_command)
       const [_, [x, y], heading, visible, pendown, penwidth, pencolor] = curr_command
-      return {position: [x, y], heading, visible, pendown, penwidth, pencolor}
+      return [target, {position: [x, y], heading, visible, pendown, penwidth, pencolor}]
     }
     case "show": {
-      return {...prev_state, visible: true}
+      return [target, {...prev_state, visible: true}]
     }
     case "hide": {
-      return {...prev_state, visible: false}
+      return [target, {...prev_state, visible: false}]
     }
     case "background": {
       background_color = curr_command[1]
@@ -532,4 +534,32 @@ export function p5 (commands) {
   return p5_calls
 }
 
+export function new_p5 (commands) {
+  const all_states = {}
+  commands.reduce((prev_state, command) => {
+    const [turtle_id, new_state] = command_to_state(prev_state, command)
+    if (!all_states[turtle_id]) all_states[turtle_id] = [turtle_init]
+    all_states[turtle_id].push(new_state)
+    return new_state
+  }, all_states)
+  const [r, g, b, _] = resolve_color(background_color)  
+  if ((r + g + b)/3 > 128) turtle_color = [0, 0, 0, 150]
+  const p5_calls = [...p5_call_root()]
+  for (const states of Object.values(all_states)) {
+    console.log(states)
+    for (let i = 1; i < states.length; ++i) {
+      const prev = states[i - 1]
+      const curr = states[i]
+      const calls = states_to_call(prev, curr)
+      for (const call of calls) {
+        p5_calls.push(call)
+      }
+      p5_calls[0] = ["background", ...resolve_color(background_color)]
+      p5_render_turtle(states[states.length - 1], p5_calls)
+    }
+  }
+  p5_calls.push(["pop"])
+  return p5_calls
+}
+