Transliteration perl->lua of thgie's implementation of Doran and Parberry's procedural quest system

doran_parberry.lua

-- procedural quest generation

math.randomseed(os.time())
local DEPTH = 3

actions = {
  goto = {
    { description = 'Just wander around and look',
      sequence = { '>explore' }
    },
    { description = 'Find out where to go and go there',
      sequence = { 'learn', '>goto' }
    }
  },
  learn = {
    { description = 'Go someplace, get something, and read what is written on it',
      sequence = { 'goto', 'get', '>read' }
    }
  },
  get = {
    { description = 'Steal it from somebody', sequence = { 'steal' } },
    { description = 'Go someplace and pick something up that is lying around there',
      sequence = { 'goto', '>gather' }
    }
  },
  steal = {
    { description = 'Go someplace, sneak up on somebody, and take something',
      sequence = { 'goto', '>stealth', '>take' }
    },
    { description = 'Go someplace, kill somebody and take something',
      sequence = { 'goto', 'kill', '>take' }
    }
  },
  spy = {
    { description = 'Go someplace, spy on somebody, return and report',
      sequence = { 'goto', '>spy', 'goto', '>report' }
    },
  },
  capture = {
    { description = 'Get something, go someplace and use it to capture somebody',
      sequence = { 'get', 'goto', '>capture' }
    }
  },
  kill = {
    { description = 'Go someplace and kill somebody',
      sequence = { 'goto', '>kill' }
    }
  },
}
motivations = {
  knowledge = {
    { description = 'Deliver item for study',
      sequence = { 'get', 'goto', '>give' }
    },
    { description = 'Spy', sequence = { 'spy' } },
    { description = 'Interview NPC',
      sequence = { 'goto', '>listen', 'goto', '>report' }
    },
    { description = 'Use an item in the field',
      sequence = { 'get', 'goto', '>use', 'goto', '>give' }
    }
  },
  comfort = {
    { description = 'Obtain luxuries',
      sequence = { 'get', 'goto', '>give' }
    },
    { description = 'Kill pests',
      sequence = { 'goto', '>damage', 'goto', '>report' }
    },
  },
  reputation = {
    { description = 'Obtain rare items',
      sequence = { 'get', 'goto', '>give' }
    },
    { description = 'Kill enemies',
      sequence = { 'goto', 'kill', 'goto', '>report' }
    },
    { description = 'Visit a dangerous place',
      sequence = { 'goto', 'goto', '>report' }
    }
  },
  serenity = {
    { description = 'Revenge, justice',
      sequence = { 'goto', '>damage' }
    },
    { description = 'Capture Criminal(1)',
      sequence = { 'get', 'goto', '>use', 'goto', '>give' }
    },
    { description = 'Capture Criminal(2)',
      sequence = { 'get', 'goto', '>use', '>capture', 'goto', '>give' }
    },
    { description = 'Check on NPC(1)',
      sequence = { 'goto', '>take', 'goto', '>give' }
    },
    { description = 'Recover lost/stolen item',
      sequence = { 'get', 'goto', '>give' }
    },
    { description = 'Rescue captured NPC',
      sequence = { 'goto', '>damage', '>escort', 'goto', '>report' }
    }
  },
  protection = {
    { description = 'Attack threatening entities',
      sequence = { 'goto', '>damage', 'goto', '>report' }
    },
    { description = 'Treat or repair (1)',
      sequence = { 'get', 'goto', '>use' }
    },
    { description = 'Treat or repair (2)',
      sequence = { 'goto', '>repair' }
    },
    { description = 'Create Diversion (1)',
      sequence = { 'get', 'goto', '>use' }
    },
    { description = 'Create Diversion (2)',
      sequence = { 'goto', '>damage' }
    },
    { description = 'Assemble fortification',
      sequence = { 'goto', 'repair' }
    },
    { description = 'Guard entity',
      sequence = { 'goto', '>defend' }
    }
  },
  conquest = {
    { description = 'Attack enemy', sequence = { 'goto', '>damage' } },
    { description = 'Steal stuff',
      sequence = { 'goto', 'steal', 'goto', '>give' }
    }
  },
  wealth = {
    { description = 'Gather raw materials', sequence = { 'goto', 'get' } },
    { description = 'Steal valuables for resale',
      sequence = { 'goto', 'steal' } },
    { description = 'Make valuables for resale',
      sequence = { '>repair' }
    }
  },
  ability = {
    { description = 'Assemble tool for new skill',
      sequence = { '>repair', '>use' }
    },
    { description = 'Obtain training materials',
      sequence = { '>get', '>use' }
    },
    { description = 'Use existing tools',
      sequence = { '>use' }
    },
    { description = 'Practice combat',
      sequence = { '>damage' }
    },
    { description = 'Practice skill',
      sequence = { '>use' }
    },
    { description = 'Research a skill(1)',
      sequence = { 'get', '>use' }
    },
    { description = 'Research a skill(1)',
      sequence = { 'get', '>experiment' }
    }
  },
  equipment = {
    { description = 'Assemble', sequence = { '>repair' } },
    { description = 'Deliver supplies',
      sequence = { 'get', 'goto', '>give' }
    },
    { description = 'Steal supplies',
      sequence = { 'steal' }
    },
    { description = 'Trade for supplies',
      sequence = { 'goto', '>exchange' }
    }
  }
}

function randomly_choose(array)
  return array[math.random(#array)]
end

local generated_subs = {}
local current_depth = 0
for action, options in pairs(actions) do
  generated_subs[action] = function ()
    local choice = options[math.random(#options)]
    local description = choice.description
    local sequence = choice.sequence
    current_depth = current_depth + 1
    local padding = string.rep('  ', current_depth)
    print(padding .. '[' .. description .. ']')
    for _, step in ipairs(sequence) do
      print(padding .. step)
      if step:sub(1, 1) ~= '>' and
         current_depth + 1 <= DEPTH
      then
        assert(generated_subs[step], 'could not find: ' .. step)
        generated_subs[step]()
      end
    end
    current_depth = current_depth - 1
  end
end

local mlist = {}
for motivation, _ in pairs(motivations) do
  table.insert(mlist, motivation)
end
local motivation = mlist[math.random(#mlist)]
local options = motivations[motivation]
choice = options[math.random(#options)]

print('generating a quest for: ' .. motivation .. ': ' .. choice.description)

for _, step in ipairs(choice.sequence) do
  print(step)
  if step:sub(1, 1) ~= '>' then
    generated_subs[step]()
  end
end