pico-8 cartridge // http://www.pico-8.com
version 42
__lua__
-- splubp data transport
-- by kistaro windrider

-- shrinko-8 hints
DEBUG = true --[[const]]

-- >8
-- utilities

-- generate standard "overlay"
-- constructor for type tt.
-- if tt.init is defined, generated
-- new calls tt.init(ret) after
-- ret is definitely not nil,
-- after calling setmetatable.
-- use to initialize mutables.
--
-- if there was a previous new,
-- it is invoked before
-- setting tt's metatable, so
-- each new will see its
-- inheritance chain.
function mknew(tt)
 local mt,oldinit,more = {__index=tt},tt.superinit,rawget(tt, "init")
 tt.new=function(ret)
  if(not ret) ret = {}
  ret.new = false
  setmetatable(ret, mt)
  if(oldinit) oldinit(ret)
  if (more) more(ret)
  return ret
 end

 if oldinit and more then
  tt.superinit = function(ret)
   oldinit(ret)
   more(ret)
  end
 elseif more then
  tt.superinit = more
 end
 return tt
end

function trim(s)
 local f, e = 1, #s
 while (f <= e and s[f]==" ") f += 1
 while (e >= f and s[e]==" ") e -= 1
 if (f<e) return sub(s,f,e)
 return ""
end

function shatter(s)
 local ret ={}
 for line in all(split(s, "\n")) do
  local row = {}
  for cell in all(split(split(line, "--")[1], " ")) do
   cell = trim(cell)
   if (#cell > 0) add(row, cell)
  end
  if (#row > 0) add(ret, row)
 end
 return ret
end

function crush(s)
 ret = ""
 for line in shatter(s) do
  for tok in line do
   ret..=tok.." "
  end
  ret = sub(ret, 1, -2).."\n"
 end
 if (#ret > 0) return sub(ret, 1, -2)
 return ""
end

-- >8
-- common

--[[preserve-keys]] splubp = mknew{
 ptr = 0x8000,
 init = function(self)
  -- fill from ffile or saved file
  self.fmts = {}
  if (not self.ffile) self.ffile, self.ptr = self:e()
  for f in all(split(self.ffile, "===", false)) do
   local tok = shatter(f)
   assert(#tok > 1, "not enough rows in "..tostr(tok)) -- debug
   assert(#tok[1] == 1 and tok[1][1][1] == ".", "bad extension row: "..tostr(tok[1])) -- debug
   self.fmts[sub(deli(tok, 1)[1], 1)] = tok
  end
 end,
}

function splubp:e()
 local ret = chr(peek(self.ptr + 2, %self.ptr))
 return ret, self.ptr + 2 + #ret
end

-- >8
-- writer

function splubp:emit_fmts()
 self.ptr = self:emit_e(self.ffile)
end

function splubp:emit_item(obj, filename)
 debug_last_emit = obj -- global debug
 filename = filename or obj._file
 obj._addr = self.ptr
 self.ptr = self:write_s(filename)
 for row in all(self.fmts[split(filename, ".")[2]]) do
  local alt = self.wdirectives[row[1]]
  if alt then
   self.ptr = alt(self, obj, row)
  else
   self.ptr = self:write_fmt(obj[row[1]], row, 2)
  end
 end
end

-- TODO: splubp.wdirectives -- a
--       table mapping non-key
--       special values to
--       functions to write them     
-- TODO: write_fmt: recursive
--       writing thing

function splubp:write_s(s)
 poke(self.ptr, #s, ord(s, 1, #s))
 return self.ptr + 1 + #s
)
end

function splubp:write_e(s)
 poke2(self.ptr, #s)
 poke(self.ptr+2, ord(s, 1, #s))
 return self.ptr + 2 + #s
end

-->8
-- loader

function splubp:s()
 local ret = chr(peek(self.ptr + 1, @self.ptr))
 return ret, self.ptr + 1 + #ret
end