Slightly more efficient fix to level_tug_crate.

Removed unnecessary variable declarations and conditional cases by using an "assume, alternate, verify assumption" pattern and reusing ax0/ay0 when they would never be referenced again.

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,
- mx0,my0,dmx,dmy,exclude_src,exclude_dst
+ is_player,o,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 +654,12 @@ function level:can_move(
  return true
 end
 
-function level:tug_crate(mx0,my0,dmx,dmy)
+-- argument is a rope operation:
+--  array of [mx0,my0,dmx,dmy]
+-- must be a free function
+--   to use as a foreach target
+function level_tug_crate(t)
+ local self,mx0,my0,dmx,dmy=level,unpack(t)
  local mxy0=_mix{mx0,my0}
  local existing=self._crates[mxy0]
  if (not existing) return
@@ -734,7 +741,7 @@ 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]
@@ -1540,22 +1547,19 @@ function rope:_tug(hypothetically)
  local blocks = {}
  for i=#ancs-1,2,-1 do
   local ops_before_trash,blocks_before_trash=self:_calc_push(ancs[i+1],ancs[i],ancs[i-1],ancs[i-2])
-  local ops_to_do,corners={}
+  local ops = {}
   for b in all(blocks_before_trash) do add(blocks, b) end
   if #ops_before_trash>0 then 
-   ops_to_do=ops_before_trash
+   ops=ops_before_trash
   else 
    local ops_after_trash,blocks_after_trash=self:_calc_push(ancs[i-2],ancs[i-1],ancs[i],ancs[i+1])
-   ops_to_do=ops_after_trash
+   ops=ops_after_trash
    for b in all(blocks_after_trash) do add(blocks,b) end
   end
 
-  local ops=ops_to_do
-
   if #ops>0 then
    if (hypothetically) return ancs,i-1,ops,blocks
-
-   for o in all(ops) do level:tug_crate(unpack(o)) end
+   foreach(ops, level_tug_crate)
    return true
   end
  end
@@ -1604,13 +1608,14 @@ function rope:_tug(hypothetically)
   end
   
   if not invalid_move then
-   if level:can_move(false,mx0,my0,dmx,dmy,1,0) then
-    if (hypothetically) return ancs,0,{{mx0,my0,dmx,dmy}},blocks
+   local mv = {mx0,my0,dmx,dmy}
+   if level:can_move(false,mv,1,0) then
+    if (hypothetically) return ancs,0,{mv},blocks
 
-    level:tug_crate(mx0,my0,dmx,dmy) 
+    level_tug_crate(mv) 
     return true
    else
-    add(blocks, {mx0,my0,dmx,dmy})
+    add(blocks, mv)
    end
   end
  end
@@ -1640,21 +1645,16 @@ function rope:_calc_push(
    smy=-smy
   end
   
-  local mx,dmx
+  local dmx=1 -- maybe push right?
   if anch.adx==-1 and a0.x>an.x+7 then
    -- push left
-   mx=ax0-1
-   dmx=-1
-  elseif anch.adx==1 and a0.x<an.x-7 then
-   -- push right
-   mx=ax0
-   dmx=1
-  else
+   ax0, dmx=ax0-1,-1
+  elseif anch.adx!=1 or a0.x>=an.x-7 then
    return {}
   end
   
   for my=my0,my1,smy do
-   add(ops,{mx,my,dmx,0})
+   add(ops,{ax0,my,dmx,0})
   end
  end
  
@@ -1666,38 +1666,26 @@ function rope:_calc_push(
    smx=-smx
   end
   
-  local my,dmy
+  local dmy=1 -- maybe push down?
   if anch.ady==-1 and a0.y>an.y+6 then
    -- push up
-   my=ay0-1
-   dmy=-1
-   
-  elseif anch.ady==1 and a0.y<an.y-6 then
-   -- push down
-   my=ay0
-   dmy=1
-  else
+   ay0,dmy=ay0-1,-1
+  elseif anch.ady!=1 or a0.y>=an.y-6 then
    return {}
   end
   
   for mx=mx0,mx1,smx do
-   add(ops,{mx,my,0,dmy})
+   add(ops,{mx,ay0,0,dmy})
   end
  end
 
  local ops2,blocked={},{}
  for o in all(ops) do
-  local mx,my,dmx,dmy=unpack(o)
-  if not level:mcoll(mx,my) then
-   -- great!
-  else
-   local crate=level:get_crate(mx,my)
-   if crate then
-    if not level:can_move(false,mx,my,dmx,dmy,0,0) then
-     add(blocked,o)
-     break
-    end
-   else
+  local mx,my=unpack(o)
+  if level:mcoll(mx,my) then
+   if (not level:get_crate(mx, my)) break
+   if not level:can_move(false,o,0,0) then
+    add(blocked,o)
     break
    end
    add(ops2,o)