can_move also takes a rope operation table

this is approximately token-neutral but performance-saving. each function parameter makes its call cost worse. When can_move is called inside a loop, we already have a table and we unpack to call can_move; moving the unpack into can_move saves us marshalling cost. It requires us to construct a table in a different spot (where we were not previously doing so) but that spot is not in a loop.

chameleonic.p8

@@ -633,10 +633,12 @@ end
 
 ropecheck=split"-0.6,0.4,0.4"
 
+-- argument "o" is a rope operation:
+-- array of [mx0,my0,dmx,dmy]
 function level:can_move(
- is_player,
+ is_player,o,exclude_src,exclude_dst
- mx0,my0,dmx,dmy,exclude_src,exclude_dst
 )
+ local mx0,my0,dmx,dmy=unpack(o)
  local mx1,my1=mx0+dmx,my0+dmy
  if (is_player and self:win_at(mx1,my1)) return true 
  if (is_player and self:get_open_pit(mx1,my1)) return wrongbleep:adequately_warned()
@@ -652,7 +654,8 @@ function level:can_move(
  return true
 end
 
--- argument is array-like: mx0,my0,dmx,dmy
+-- argument is a rope operation:
+-- array of [mx0,my0,dmx,dmy]
 function level:tug_crate(t)
  local mx0,my0,dmx,dmy=unpack(t)
  local mxy0=_mix{mx0,my0}
@@ -736,7 +739,7 @@ function player:update()
   else
    local x,y=self.x,self.y
    local function try_move(dx,dy,f)
-    if level:can_move(true,x,y,dx,dy,0,2) then 
+    if level:can_move(true,{x,y,dx,dy},0,2) then 
      self.todo=f 
      self.cooldown=3
      local t=f[#f]
@@ -1604,7 +1607,7 @@ function rope:_tug(hypothetically)
   
   if not invalid_move then
    local mv = {mx0,my0,dmx,dmy}
-   if level:can_move(false,mx0,my0,dmx,dmy,1,0) then
+   if level:can_move(false,mv,1,0) then
     if (hypothetically) return ancs,0,{mv},blocks
 
     level:tug_crate(mv) 
@@ -1693,7 +1696,7 @@ function rope:_calc_push(
   else
    local crate=level:get_crate(mx,my)
    if crate then
-    if not level:can_move(false,mx,my,dmx,dmy,0,0) then
+    if not level:can_move(false,o,0,0) then
      add(blocked,o)
      break
     end