onclimb = function(...)

    onclimb = function()

function initialise_ziggurat(z)

function initialise_ziggurat(z, portal)
  if portal then
    z.props = portal.props
  end

function ziggurat_initialiser()

function ziggurat_initialiser(portal)

  initialise_ziggurat(zig())

  initialise_ziggurat(zig(), portal)

local function depth_if(spec, fn)

local function spec_if(fn, spec)

local function depth_ge(lev, spec)
  return depth_if(spec, function ()
                          return zig().depth >= lev
                        end)

local function depth_ge(lev)
  return function ()
           return zig().depth >= lev
         end
end
local function depth_range(low, high)
  return function ()
           local depth = zig().depth
           return depth >= low and depth <= high
         end

local function depth_lt(lev, spec)
  return depth_if(spec, function ()
                          return zig().depth < lev
                        end)

local function depth_lt(lev)
  return function ()
           return zig().depth < lev
         end

local mons_populations = {
  -- Dress up monster sets a bit.
  "place:Elf:$ w:300 / deep elf blademaster / deep elf master archer / " ..
    "deep elf annihilator / deep elf sorcerer / deep elf demonologist",
  "place:Orc:$ w:120 / orc warlord / orc knight / stone giant",
  "place:Vault:$",
  with_props("place:Slime:$", { jelly_protect = true }),
  "place:Snake:$",
  "place:Lair:$",
  "place:Tomb:$ w:200 / greater mummy",
  "place:Crypt:$",
  "place:Abyss",
  "place:Shoal:$",
  "place:Coc:$",
  "place:Geh:$",
  "place:Dis:$",
  "place:Tar:$",
  "daeva / angel",
  depth_ge(6, "place:Pan w:400 / w:15 pandemonium lord"),
  depth_lt(6, "place:Pan")
}

local mons_populations = { }
local function mset(...)
  util.foreach({ ... }, function (spec)
                          table.insert(mons_populations, spec)
                        end)
end

local function mons_random_gen(x, y, nth)
  set_random_floor_colour()
  local mgen = nil
  while not mgen do
    mgen = monster_creator_fn(util.random_from(mons_populations))
    if mgen then
      mgen = mgen.fn
    end
  end
  return mgen(x, y, nth)

local function mset_if(condition, ...)
  mset(unpack(util.map(util.curry(spec_if, condition), { ... })))

mset("place:Elf:$ w:300 / deep elf blademaster / deep elf master archer / " ..
     "deep elf annihilator / deep elf sorcerer / deep elf demonologist",
     "place:Orc:$ w:120 / orc warlord / orc knight / stone giant",
     "place:Vault:$",
     with_props("place:Slime:$", { jelly_protect = true }),
     "place:Snake:$",
     with_props("place:Lair:$", { weight = 5 }),
     "place:Tomb:$ w:200 / greater mummy",
     "place:Crypt:$",
     "place:Abyss",
     "place:Shoal:$",
     "place:Coc:$",
     "place:Geh:$",
     "place:Dis:$",
     "place:Tar:$",
     "daeva / angel")
mset_if(depth_ge(6), "place:Pan w:400 / w:15 pandemonium lord")
mset_if(depth_lt(6), "place:Pan")

local mons_generators = {
  mons_random_gen,
  depth_ge(6, mons_drac_gen),
  depth_ge(8, mons_panlord_gen)
}

mset_if(depth_ge(6), mons_drac_gen)
mset_if(depth_ge(8), mons_panlord_gen)

  return util.map(monster_creator_fn,
                  util.catlist(mons_populations, mons_generators))

  return util.map(monster_creator_fn, mons_populations)

  return ziggurat_vet_monster(util.random_from(ziggurat_monster_creators()))

  return ziggurat_vet_monster(
           util.random_weighted_from(
             'weight',
             ziggurat_monster_creators()))

--crawl.mpr("area=" .. area .. ", a: " .. a .. ", lx=" .. left.x .. ", rx=" .. right.x)  
  

--crawl.mpr("area=" .. area .. ", a: " .. a .. ", lx=" .. left.x .. ", rx=" .. right.x)

function util.curry(fn, ...)
  local params = { ... }
  if #params == 1 then
    return function (...)
             return fn(params[1], ...)
           end
  else
    return function (...)
             return fn(unpack(util.catlist(params, ...)))
           end
  end
end

end
function util.foreach(list, fn)
  for _, val in ipairs(list) do
    fn(val)
  end

end
function util.random_weighted_from(weightfn, list)
  if type(weightfn) ~= "function" then
    weightfn = function (table)
                 return table[weightfn]
               end
  end
  local cweight = 0
  local chosen = nil
  util.foreach(list,
               function (e)
                 local wt = weightfn(e) or 10
                 cweight = cweight + wt
                 if crawl.random2(cweight) < wt then
                   chosen = e
                 end
               end)
  return chosen