small demo of pico-8's runtime drag-and-drop interface

serial.p8

--[[
    0x800           dropped file   //  stat(120) returns true when data is available
    0x802           dropped image  //  stat(121) returns true when data is available
    0x804           stdin
    0x805           stdout
    0x806           file specifed with: pico8 -i filename
    0x807           file specifed with: pico8 -o filename
]]

function readline(maxlen)
 maxlen=maxlen or 1000
 local s=""
 for i=1,maxlen do
  serial(0x800,0,1)
  local ch=chr(@0)
  if ch=="\n" then
   return s
  end
  s..=ch
 end
 assert(nil,"line too long")
end

-- -- zep's verison, from `load #activity`:
-- -- tbh something like might be better than my
-- -- way above

-- while (stat(120)) do
--  local len=
--   serial(0x800, 0, 16000)
--  
--  for i=1,len do
--   local c=chr(@(i-1))
--   assert(c, @(i-1))
--   if (c=="\n") then
--    process_line(ln)
--    ln=""
--   else
--     ln..=c
--    end
--  end
--  
--  print_stats() flip()
--  
-- end
-- process_line(ln) --leftovers

function _init()
 lines={}
end

function _update60()
 if stat(120) then
  local s=readline()
  add(lines,s)
 end
end

function _draw()
 cls(1)
 if #lines==0 then
  print"drag-drop a text file"
 else
  for l in all(lines) do
   print(l)
  end
 end
end