pac4

--a shortcut for string.format
sf = string.format

--[[
helper function
split a line into a table
--]]

function split(source, delimiters)
        local elements = {}
        local pattern = '([^'..delimiters..']+)'
        string.gsub(source, pattern, function(value) elements[#elements + 1] =     value;  end);
        return elements
  end
--[[
helper function to ignore comments in data file
returns true if String starts with Start, false otherwise
--]]
function startsWith(String,Start)
   return string.sub(String,1,string.len(Start))==Start
end
--[[
helper function to determine
from the row number which way
the turtle is going and which
way to turn when done
it illustrates some advanced
functional features of lua
like returning a sequence and
returning a function as a value
end
--]]

function leftEnd()
  turtle.turnLeft()
  turtle.back()
  turtle.turnLeft()
end

function rightEnd()
  turtle.turnRight()
  turtle.back()
  turtle.turnRight()
end

function stripes(i,length)
if i % 2 == 0 then
  return 1,length, 1, leftEnd
end
  return length,1,rightEnd
end
-- assumes turtle is on the spot
-- being acted upon
action = {
 [0] = function() turtle.back() end,
 [2] = function()
   turtle.select(2)
   turle.placeUp()
   turtle.select(1)
   turtle.back()
 end,

 [1] = function()
   turtle.select(1)
   turtle.back()
   turtle.place()
 end,
 [3] = function()
   turtle.select(3)
   turtle.placeUp()
   turtle.select(1)
   turtle.back()
 end
 }

--[[ ----- begin the main work -------------------------
--]]
io.input("maze.dat")
io.output("debug.txt")
local lines = {}
-- read the file into table 'lines'
-- split by lines and each line by commas
-- ignore comment lines in the line that begin with "#"
for line in io.lines() do
   if not startsWith(line, "#") then
       row = split(line,",")
       table.insert(lines, row)
    end
end
io.input():close()
-- build the maze
--remove the maze sizes from the list
rows = lines[1][1]
table.remove(lines,1)
io.write(sf("%d\n",rows))

columns = lines[1][1]
table.remove(lines,1)
io.write(sf("%d\n",columns))
for i, l in ipairs(lines) do
   jstart,jend,jstep,turn = stripe(i,table.getn(l))
   for j = jstart,jend, jstep do
      actionIndex = l[j]
      io.write(sf("(%d %d)",j,actionIndex))
       --action[actionIndex]()
    end
    --turn()
    io.write("\n")
--    return
end
io.output():close()