On Fri, 1 May 2020, Hans Hagen wrote:

> On 5/1/2020 6:12 AM, Jairo A. del Rio wrote:
>> I've adapted the following code to make mazes in LuaLaTeX and ConTeXt: 
>> https://www.rosettacode.org/wiki/Maze_generation#Lua
>> 
>> I defined a modified version to make content visible to TeX and I saved in 
>> a file named maze.lua:
>> 
>> function make_maze_tex(w, h, m)
>>    w = w or 16
>>    h = h or 8
>>
>>    local map = initialize_grid(w*2+1, h*2+1)
>>
>>    function walk(x, y)
>>      map[y][x] = false
>>
>>      local d = { 1, 2, 3, 4 }
>>      shuffle(d)
>>      for i, dirnum in ipairs(d) do
>>        local xx = x + dirs[dirnum].x
>>        local yy = y + dirs[dirnum].y
>>        if map[yy] and map[yy][xx] then
>>          map[avg(y, yy)][avg(x, xx)] = false
>>          walk(xx, yy)
>>        end
>>      end
>>    end
>>
>>    walk(math.random(1, w)*2, math.random(1, h)*2)
>> 
>> ...ext/tex/texmf-context/tex/context/base/mkiv/supp-ran.lua:30: C stack 
>> overflow 
>> Why does it happen? I guess it has something to do with math.randomseed, 
>> but I don't know how to avoid this error message.
> no, it's just lua running out of stack space so it depends on the binary 
> (and als the initial random value)

But why is it running out of stack? Isn't the walk function tail recursive, in which case it should not cause a stack overflow (https://www.lua.org/pil/6.3.html).

Aditya