string2Tiles.lua

-- transforms a pretty-but-difficult string into an ugly-but-easy array for tilemaps

local function string2Tiles(str)
  local tiles = {}

  local row_length = #(str:match("[^\n]+"))

  for x = 1,row_length,1 do 
    tiles[x] = {}
  end

  local x,y = 1,1
  for row in str:gmatch("[^\n]+") do
    assert(#row == row_length, 'Map is not squared: length of row ' .. tostring(y) .. ' should be ' .. tostring(row_length) .. ', but it is ' .. tostring(#row))
    x = 1
    for tile in row:gmatch(".") do
      tiles[x][y] = tile
      x = x + 1
    end
    y=y+1
  end
  
  setmetatable(tiles, { __call = function(self, x,y) return self[x][y] end })

  return tiles
end

local function printMap(map)
  local buffer = {}
  for x,column in ipairs(map) do
    table.insert(buffer, "\n  { '" .. table.concat(column, "', '") .. "' }")
  end
  print( '{' .. table.concat(buffer, ',\n') .. '\n}' )
end

local str = [[
  1***2  
  *   *  
  * 0 *  
  *   *  
  3***4  
]]

local tiles = string2Tiles(str)

print('string:')
print(str)

print('tiles:')
printMap(tiles)

print('tiles[5][3]:', tiles[5][3])
print('tiles(5,3):', tiles(5,3))

--[[ Output:

string:
  1***2  
  *   *  
  * 0 *  
  *   *  
  3***4  

tiles:
{
  { ' ', ' ', ' ', ' ', ' ' },

  { ' ', ' ', ' ', ' ', ' ' },

  { '1', '*', '*', '*', '3' },

  { '*', ' ', ' ', ' ', '*' },

  { '*', ' ', '0', ' ', '*' },

  { '*', ' ', ' ', ' ', '*' },

  { '2', '*', '*', '*', '4' },

  { ' ', ' ', ' ', ' ', ' ' },

  { ' ', ' ', ' ', ' ', ' ' }
}
tiles[5][3]:	0
tiles(5,3):	0

]]