Pattern help

--[[
example format (furnace):
m@minecraft;s@stone;n@none
m:s&m:s&m:s
m:s&n:n&m:s
m:s&m:s&m:s
]]--

local function parse( str )
	local tLines = {}
	for line in str:gmatch( "[^\r\n]+" ) do
		tLines[ #tLines + 1 ] = line
	end
	print( 'parsed lines' )
	print( #tLines )
	print( 'starting tShortcuts' )
	local tShortcuts = {}
	if tLines[ 1 ]:find( "@" ) then
		print( "found shortcuts" )
		--encoding is present
		for s, o in tLines[ 1 ]:gmatch( "([^@]+)@(^;+);?" ) do
			tShortcuts[ s ] = o
		end
		table.remove( tLines, 1 )
	else
		print( 'no shortcuts' )
	end
	print( #tLines )
	print( #tShortcuts )
	local tInv = {}
	local row = 0
	print( 'compiling tInv' )
	for _, str in ipairs( tLines ) do
		local l = 1
		print( str )
		for mod, item in str:gmatch( "([^:]+):(/>[^:\r\n]+)&?" ) do
			print('')
			tInv[ (row * 4) + l ] = ( tShortcuts[ mod ] or mod ) .. ":" .. ( tShortcuts[ item ] or item )
			l = l + 1
		end
		row = row + 1
	end
	return tInv
end

m@minecraft;s@stone;n@none
m:s&m:s&m:s
m:s&n&m:s
m:s&m:s&m:s

{
  [1] = "minecraft:stone",
  [2] = "minecraft:stone",
  [3] = "minecraft:stone",

  [5] = "minecraft:stone",
  [6] = "null:null",
  [7] = "minecraft:stone",

  [9] = "minecraft:stone",
  [10] = "minecraft:stone",
  [11] = "minecraft:stone",
}

{
  [1] = "m:s&m",
  [2] = "s&m:s",
  [5] = "m:s&n&m",
  [10] = "s&m:s",
  [9] = "m:s&m",
}

local function parse( str )
	local tLines = {}
	for line in str:gmatch( "[^\r\n]+" ) do
		tLines[ #tLines + 1 ] = line
	end
	print( 'parsed lines' )
	print( #tLines )
	print( 'starting tShortcuts' )
	local tShortcuts = {}
	if tLines[ 1 ]:find( "@" ) then
		print( "found shortcuts" )
		--encoding is present
		for s, o in tLines[ 1 ]:gmatch( "([^@]+)@([^;]+);?" ) do
			tShortcuts[ s ] = o
			print( s .. " = " .. o )
		end
		table.remove( tLines, 1 )
	else
		print( 'no shortcuts' )
	end
	local tInv = {}
	local row = 0
	print( 'compiling tInv' )
	for _, str in ipairs( tLines ) do
		local l = 1
		for mod, item in str:gmatch( "([^:]+):(/>[^:\r\n]+)&" ) do
			tInv[ (row * 4) + l ] = ( tShortcuts[ mod ] or mod ) .. ":" .. ( tShortcuts[ item ] or item )
			l = l + 1
		end
		row = row + 1
	end
	return tInv
end