multi-step shot prototype

nothing reaches this new logic yet, and multiple steps aren't drawn

vacuum_gambit.p8

@@ -257,22 +257,30 @@ function updategame()
    if(es:hitship(ps)) eship_collider:yoink(es)
   end
   ebullets:strip(function(eb)
-   -- loopify this when split moves implemented
-   if (eb:move()) return true
-   if (not collides(pbox, hurtbox(eb))) return
-   ps:hitbullet(eb)
-   return eb:hitship(ps)
+   local disposition
+   repeat
+    disposition=eb:step()
+    if collides(pbox, hurtbox(eb)) then
+     ps:hitbuillet(eb)
+     if (eb:hitship(ps)) return true
+    end
+   until disposition
+   return disposition == "dead"
   end)
  else
-  ebullets:stripmove()
+  ebullets:strip(function(eb) repeat until eb:step() end)
  end
 
  pbullets:strip(function(pb)
-  if (pb:move()) return true
+  local disposition
+  repeat
+   disposition=pb:step()
    for es in eship_collider:iterate_collisions(hurtbox(pb)) do
     if (es:hitbullet(pb)) eship_collider:yoink(es)
     if (pb:hitship(es)) return true
    end
+  until disposition
+  return disposition == "dead"
  end)
  
  intangibles_fg:stripmove()
@@ -692,9 +700,10 @@ end
 --   default: die, return true.
 --   returns whether to delete
 --   the bullet
--- die -- on-removal event,
---   default no-op
-bullet_base = mknew{ }
+bullet_base = mknew{
+ steps=1,
+ current_step=0
+}
 
 gun_base = mknew{ 
  shoot_ready = -32768,
@@ -820,11 +829,13 @@ function bullet_base:hitship(_)
  return true
 end
 
-function bullet_base:move()
+function bullet_base:step()
+ self.current_step=(self.current_step+1)%self.steps
  self.x += self.dx
  self.y += self.dy
  if (self.f) self.f -= 1
- return (self.y > 130) or (self.y < -self.height*8) or (self.f and self.f < 0) or (self.x > 128) or (self.x < -self.width*8)
+ if ((self.y > 130) or (self.y < -self.height*8) or (self.f and self.f < 0) or (self.x > 128) or (self.x < -self.width*8)) return "dead"
+ if (self.current_step == 0) return "stop"
 end
 
 function bullet_base:draw()