Export PICO-8 map to TMX format

 -- the width and height of the map
 local width,height=0,0

 -- create the filename from the current date and time
 local filename=""
 for i=90,95 do
  filename=filename..sub("0"..stat(i),-2)
 end

 -- ascertain the width and height of our map
 for y=0,127 do
  for x=0,63 do
   local t=mget(x,y)
   if t>0 then
    if x>width then width=x+1 end
    if y>height then height=y+1 end
   end
  end
 end

 -- start building an xml string to write to file
 local tmx='<?xml version="1.0" encoding="UTF-8"?>\n'
 tmx=tmx..'<map version="1.2" tiledversion="1.3.1" orientation="orthogonal" renderorder="right-down" compressionlevel="0" width="'..width..'" height="'..height..'" tilewidth="8" tileheight="8" infinite="0" nextlayerid="2" nextobjectid="1">\n'
 tmx=tmx..' <editorsettings>\n'
 tmx=tmx..'  <export target="'..filename..'.lua" format="lua"/>\n'
 tmx=tmx..' </editorsettings>\n'
 tmx=tmx..' <tileset firstgid="1" name="'..filename..'" tilewidth="8" tileheight="8" tilecount="256" columns="16">\n'
 tmx=tmx..'  <image source="'..filename..'.png" trans="000000" width="128" height="128"/>\n'
 tmx=tmx..' </tileset>\n'
 tmx=tmx..' <layer id="1" name="pico8" width="'..width..'" height="'..height..'">\n'
 tmx=tmx..'  <data encoding="csv">\n'

 -- add the map data to the string in csv format
 local comma=","
 for y=0,height-1 do
  for x=0,width-1 do
   if y==height-1 and x==width-1 then comma="" end
   tmx=tmx..mget(x,y)..comma
  end
  tmx=tmx..'\n'
 end

 -- complete the xml string
 tmx=tmx..'  </data>\n'
 tmx=tmx..' </layer>\n'
 tmx=tmx..'</map>\n'

 -- dump the xml to a p8l file in the current directory (remove the .p8l extension manually)
 printh(tmx,filename..".tmx",true)

 -- dump the xml to the clipboard (paste into a new file and save as .tmx)
 printh(tmx,"@clip",true)