build/ludus.mjs

@@ -6,22 +6,25 @@ let result = null
 
 export function run (source) {
   const output = mod.ludus(source).value
+  // console.log(output)
   result = JSON.parse(output)
   return result
 }
 
 export function stdout () {
-  if (!result) return ""
   return result.io.console.data
 }
 
 export function turtle_commands () {
-  if (!result) return []
   return result.io.turtle.data
 }
 
+export function p5_calls () {
+  return p5_call_list
+}
+
 export function svg () {
-  // TODO
+  
 }
 
 const turtle_init = {
@@ -52,14 +55,13 @@ const colors = {
 	aqua: [0, 255, 25, 255],
 }
 
-function resolve_color (color) {
+let turtle_states = [turtle_init]
-  if (typeof color === 'string') return colors[color]
-  if (typeof color === 'number') return [color, color, color, 255]
-  if (Array.isArray(color)) return color
-}
-
 let background_color = "black"
 
+function last_state () {
+  return turtle_states[turtle_states.length - 1]
+}
+
 function add (v1, v2) {
   const [x1, y1] = v1
   const [x2, y2] = v2
@@ -74,84 +76,83 @@ function mult (vector, scalar) {
 function unit_of (heading) {
   const turns = -heading + 0.25
   const radians = turn_to_rad(turns)
-  return [Math.cos(radians), Math.sin(radians)]
+  [Math.cos (radians), Math.sin(radians)]
 }
 
-function command_to_state (prev_state, curr_command) {
+function command_to_state (previous, command) {
-  const verb = curr_command[0]
+  const verb = command[0]
   switch (verb) {
     case "goto": {
-      const [_, x, y] = curr_command
+      const [_, x, y] = command
-      return {...prev_state, position: [x, y]}
+      return {...previous, position: [x, y]}
     }
     case "home": {
-      return {...prev_state, position: [0, 0], heading: 0}
+      return {...previous, position: [0, 0], heading: 0}
     }
     case "right": {
-      const [_, angle] = curr_command
+      const [_, angle] = command
-      const {heading} = prev_state
+      const {heading} = previous
-      return {...prev_state, heading: heading + angle}
+      return {...previous, heading: heading + angle}
     }
     case "left": {
-      const [_, angle] = curr_command
+      const [_, angle] = command
-      const {heading} = prev_state
+      const {heading} = previous
-      return {...prev_state, heading: heading - angle}
+      return {...previous, heading: heading - angle}
     }
     case "forward": {
-      const [_, steps] = curr_command
+      const [_, steps] = command
-      const {heading, position} = prev_state
+      const {heading, position} = previous
       const unit = unit_of(heading)
       const move = mult(unit, steps)
-      return {...prev_state, position: add(position, move)}
+      return {...previous, position: add(position, move)}
     }
     case "back": {
-      const [_, steps] = curr_command
+      const [_, steps] = command
-      const {heading, position} = prev_state
+      const {heading, position} = previous
       const unit = unit_of(heading)
       const move = mult(unit, -steps)
-      return {...prev_state, position: add(position, move)}
+      return {...previous, position: add(position, move)}
     }
     case "penup": {
-      return {...prev_state, pendown: false}
+      return {...previous, pendown: false}
     }
     case "pendown": {
-      return {...prev_state, pendown: true}
+      return {...previous, pendown: true}
     }
     case "pendwith": {
-      const [_, width] = curr_command
+      const [_, width] = command
-      return {...prev_state, penwidth: width}
+      return {...previous, penwidth: width}
     }
     case "pencolor": {
-      console.log(curr_command)
+      if (command.length = 2) {
-      if (curr_command.length = 2) {
+        const [_, color] = command
-        const [_, color] = curr_command
+        return {...previous, pencolor: color}
-        return {...prev_state, pencolor: color}
       } else {
-        const [_, r, g, b, a] = curr_command
+        const [_, r, g, b, a] = command
-        return {...prev_state, pencolor: [r, g, b, a]}
+        return {...previous, pencolor: [r, g, b, a]}
       }
     }
     case "setheading": {
-      const [_, heading] = curr_command
+      const [_, heading] = command
-      return {...prev_state, heading: heading}
+      return {...previous, heading: heading}
     }
     case "loadstate": {
-      const [_, x, y, heading, visible, pendown, penwidth] = curr_command
+      const [_, x, y, heading, visible, pendown, penwidth] = command
       // there are 7 fixed-arity arguments
       // color will either be the last one or four
-      let pencolor = curr_command.slice(7)
+      let pencolor = command.slice(7)
       // if there's one, it's a string, unpack it
       if (pencolor.length = 1) pencolor = pencolor[0]
       return {position: [x, y], heading, visible, pendown, penwidth, pencolor}
     }
     case "show": {
-      return {...prev_state, visible: true}
+      return {...position, visible: true}
     }
     case "hide": {
-      return {...prev_state, visible: false}
+      return {...position, visible: false}
     }
     case "background": {
-      let color = curr_command.slice(1)
+      let color = command.slice(1)
       if (color.lengh = 1) color = color[0]
       background_color = color
       return
@@ -165,26 +166,8 @@ function are_eq (v1, v2) {
   return (x1 === x2) && (y1 === y2)
 }
 
-function states_to_call (prev, curr) {
+function state_to_call (prev, curr) {
-  const calls = []
+  
-  // whose state should we use?
-  // pen states will only differ on more than one property
-  // if we use `loadstate`
-  // my sense is `prev`, but that may change
-  if (prev.pendown && !are_eq(prev.position, curr.position)) {
-    calls.push(["line", prev.position[0], prev.position[1], curr.position[0], curr.position[1]])
-  }
-  if (curr.pencolor !== prev.pencolor) {
-    if (Array.isArray(curr.pencolor)) {
-      calls.push(["stroke", ...curr.pencolor])
-    } else {
-      calls.push(["stroke", curr.pencolor])
-    }
-  }
-  if (curr.penwidth !== prev.penwidth) {
-    calls.push(["strokeWeight", curr.penwidth])
-  }
-  return calls
 }
 
 const turtle_radius = 20
@@ -193,65 +176,47 @@ const turtle_angle = 0.385
 
 const turtle_color = [255, 255, 255, 150]
 
-const p5_call_root = [
+let p5_call_list = []
-  ["background", ...resolve_color(background_color)],
+
-  ["stroke", ...resolve_color(turtle_init.pencolor)]
+function add_p5_call (call) {
-]
+  p5_call_list.push(call)
+}
 
 function rotate (vector, heading) {
   const radians = turn_to_rad(heading)
   const [x, y] = vector
   return [
-    (x * Math.cos (radians)) - (y * Math.sin (radians)),
+    (x * cos (radians)) - (y * sin (radians)),
-    (x * Math.sin (radians)) + (y * Math.cos (radians))
+    (x * sin (radians)) + (y * cos (radians))
   ]
 }
 
 function turn_to_rad (heading) {
-  return heading * 2 * Math.PI
+  heading * 2 * Math.PI
 }
 
-function render_turtle (state, calls) {
+function render_turtle () {
+  const state = last_state ()
   if (!state.visible) return
-  calls.push(["push"])
   const [r, g, b, a] = turtle_color
-  calls.push(["fill", r, g, b, a])
+  add_call("fill", r, g, b, a)
-  const {heading, pencolor, position: [x, y], pendown} = state
+  const {heading, pencolor: [pen_r, pen_g, pen_b, pen_a], position: [x, y], pendown} = state
   const origin = [0, turtle_radius]
   const [x1, y1] = origin
   const [x2, y2] = rotate(origin, turtle_angle)
   const [x3, y3] = rotate(origin, -turtle_angle)
-  calls.push(["translate", x, y])
+  add_p5_call(["push"])
-  calls.push(["rotate", turn_to_rad(heading)])
+  add_p5_call(["translate", x, y])
-  calls.push(["noStroke"])
+  add_p5_call(["rotate", turn_to_rad(heading)])
-  calls.push(["beginShape"])
+  add_p5_call(["noStroke"])
-  calls.push(["vertex", x1, y1])
+  add_p5_call(["beginShape"])
-  calls.push(["vertex", x2, y2])
+  add_p5_call(["vertex", x1, y1])
-  calls.push(["vertex", x3, y3])
+  add_p5_call(["vertex", x2, y2])
-  calls.push(["endShape"])
+  add_p5_call(["vertex", x3, y3])
-  calls.push(["stroke", ...resolve_color(pencolor)])
+  add_p5_call(["endShape"])
-  if (pendown) calls.push(["line", 0, 0, x1, y1])
+  add_p5_call(["stroke", pen_r, pen_g, pen_b, pen_a])
-  calls.push(["pop"])
+  if (pendown) add_p5_call(["line", 0, 0, x1, y1])
-  return calls
+  add_p5_call(["pop"])
 }
 
-export function p5_calls (commands) {
+
-  const states = [turtle_init]
-  commands.reduce((prev_state, command) => {
-    const new_state = command_to_state(prev_state, command)
-    states.push(new_state)
-    return new_state
-  }, turtle_init)
-  const p5_calls = [...p5_call_root]
-  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)]
-  render_turtle(states[states.length - 1], p5_calls)
-  return p5_calls
-}

postlude.ld

@@ -3,5 +3,7 @@
 & the goal is to output any global state held in Ludus
 & this does not have base loaded into it, only prelude: must be pure Ludus
 
+print! ("running postlude")
+
 store! (turtle_state, turtle_init)
 store! (turtle_commands, [])

prelude.ld

@@ -1106,14 +1106,90 @@ let turtle_init = #{
 box turtle_commands = []
 box turtle_state = turtle_init
 
+& fn reset_turtle! {
+& 	"Resets the turtle to its original state."
+& 	() -> store! (turtle_states, [turtle_init])
+& }
+
 fn add_command! (command) -> {
 	update! (turtle_commands, append! (_, command))
 	let prev = unbox (turtle_state)
 	let curr = apply_command (prev, command)
 	store! (turtle_state, curr)
+	& let call = state/call ()
+	& if call then { add_call! (call); :ok } else :ok
 	:ok
 }
 
+& fn make_line ((x1, y1), (x2, y2)) -> (:line, x1, y1, x2, y2)
+
+& let turtle_radius = 20
+
+& let turtle_angle = 0.385
+
+& let turtle_color = (255, 255, 255, 150)
+
+& fn render_turtle! () -> {
+& 	let state = do turtle_states > unbox > last
+& 	if state :visible?
+& 		then {
+& 			let (r, g, b, a) = turtle_color
+& 			add_call! ((:fill, r, g, b, a))
+& 			let #{heading
+& 				:pencolor (pen_r, pen_g, pen_b, pen_a)
+& 				:position (x, y)
+& 				pendown?
+& 				...} = state
+& 			let origin = mult ((0, 1), turtle_radius)
+& 			let (x1, y1) = origin
+& 			let (x2, y2) = rotate (origin, turtle_angle)
+& 			let (x3, y3) = rotate (origin, neg (turtle_angle))
+& 			add_call! ((:push))	
+& 			add_call! ((:translate, x, y))
+& 			add_call! ((:rotate, turn/rad (heading)))
+& 			add_call! ((:noStroke))
+& 			add_call! ((:beginShape))
+& 			add_call! ((:vertex, x1, y1))
+& 			add_call! ((:vertex, x2, y2))
+& 			add_call! ((:vertex, x3, y3))
+& 			add_call! ((:endShape))
+& 			& there's a happy bug here: the stroke will be the same width as the pen width. Keep this for now. Consider also showing the pen colour here?
+& 			add_call! ((:stroke, pen_r, pen_g, pen_b, pen_a))
+& 			if pendown? then add_call! ((:line, 0, 0, x1, y1)) else nil
+& 			add_call! ((:pop))
+& 			:ok
+& 		}
+& 		else :ok
+& }
+
+& fn state/call () -> {
+& 	let cmd = do turtle_commands > unbox > last > first
+& 	let states = unbox (turtle_states)
+& 	let curr = last (states)
+& 	let prev = at (states, sub (count (states), 2))
+& 	match cmd with {
+& 		:forward -> if curr :pendown?
+& 			then make_line (prev :position, curr :position)
+& 			else nil
+& 		:back -> if curr :pendown?
+& 			then make_line (prev :position, curr :position)
+& 			else nil
+& 		:home -> if curr :pendown?
+& 			then make_line (prev :position, curr :position)
+& 			else nil
+& 		:goto -> if curr :pendown?
+& 			then make_line (prev :position, curr :position)
+& 			else nil
+& 		:penwidth -> (:strokeWeight, curr :penwidth)
+& 		:pencolor -> {
+& 			let (r, g, b, a) = curr :pencolor
+& 			(:stroke, r, g, b, a)
+& 		}
+& 		:clear -> (:background, 0, 0, 0, 255)
+& 		_ -> nil
+& 	}
+& }
+
 fn forward! {
 	"Moves the turtle forward by a number of steps. Alias: fd!"
 	(steps as :number) -> add_command! ((:forward, steps))
@@ -1175,7 +1251,7 @@ let pw! = penwidth!
 
 fn background! {
 	"Sets the background color behind the turtle and path. Alias: bg!"
-	(color as :keyword) -> add_command! ((:background, color))
+	(color as :keyword) -> add_command! ((:background, :color))
 	(gray as :number) -> add_command! ((:background, gray, gray, gray, 255))
 	((r as :number, g as :number, b as :number)) -> add_command! ((:background, r, g, b, 255))
 	((r as :number, g as :number, b as :number, a as :number)) -> add_command! ((:background, r, g, b, a))
@@ -1262,7 +1338,6 @@ fn apply_command {
 		(:loadstate, x, y, heading, visible?, pendown?, penwidth, r, g, b, a) -> #{:position (x, y), heading, visible?, pendown?, penwidth, :pencolor (r, g, b, a)}
 		(:show) -> assoc (state, :visible?, true)
 		(:hide) -> assoc (state, :visible?, false)
-		(:background, _) -> state
 	}
 }