It would be helpful if calling color() to change the default color would return the previously default color. I am currently using a snippet like this to restore a previous default color:

 t=band(peek(24357),15)
 color(c)
 blah blah
 color(t)

Further, if color() didn't actually do color(0) we could use it JUST to check the color without changing it!

Zep has said on Twitter that the next version (0.1.12) would have this behaviour, as well as pal(), cursor() and several others.

Could write a function I suppose:

-- push me pull you colors
-- written by dw817 (01-28-20)

function _init()

colt={}

-- maximum # of colors to
-- remember.
cstack=32

cls()

for z=0,3 do

for i=0,15 do
  colr(rnd(15)+1)
  rectfill(i*8,60,i*8+6,63)
end

repeat
  flip()
until btnp()>0

for i=15,0,-1 do
  colr(-1)
  rectfill(i*8,65,i*8+6,68)
end

repeat
  flip()
until btnp()>0

end

end

function colr(n)
local c=colt[#colt]
  if n>=0 then
    color(n)
    if #colt==cstack then
      del(colt,colt[1])
    end
    add(colt,n)
  else
    color(c)
    del(colt,c)
  end
end

While I agree that the API should do this by default for all state-setting calls, for the time being you should remember that you can replace the API if you want to, e.g.:

hooked_color=color
function color(...)
  local t=peek(24357)
  hooked_color(...)
  return t
end

(Note that "..." is a Lua language feature for argument forwarding, and not just my own shorthand.)

Also, no need to band(,15). The value in 24357 is exactly the one passed into color(). The upper 4 bits are only nonzero if you set them nonzero yourself, e.g. 0xb8 for red/green xmas patterns. You'd want to preserve them and not mask them off.