Text based adventure game navigation

Question

I have a problem with my code. I made so much code, and now I need to place ends, which I cannot figure out how to do because I need to line everything up and then place at least 5 or 6 ends in the right places. I am fairly new to Lua and I'm sure that there's a better way to go about this, so if there is, tell me in your answer. Also, this code is unfinished.

math.randomseed(os.clock())
math.random();math.random();math.random()
local function navigate()
  print("Where would you like to go?")
  print("Somewhere peaceful(type peaceful), somewhere dangerous(type dangerous), or somewhere civilized?")
  local destination = io.read() 
  if destination == "peaceful" then
    local event = math.random(5)
    if event == 1 then
      print("You find a leafy forest.")
      print("What would you like to do? Search, Cut tree, Inventory")
      local action = io.read()
      if action == "search" then
        local searchevent = math.random(3)
          if searchevent == 1 then
          require("battle")
          elseif searchevent == 2 then
            lootdrop = math.random(5)
            if lootdrop == 1 then
              print("You found an abandoned sword. You pick it up.")
              if g_inventory1 == nil then
                g_inventory1 = "a sword"
              elseif g_inventory2 == nil then
                g_inventory2 = "a sword"
              elseif g_inventory3 == nil then
                g_inventory3 = "a sword"
              else
                print("You don't have room for this sword.Type 'leave it' or replace items. Items to replace:")
                print(g_inventory1)
                print(g_inventory2)
                print(g_inventory3)
                replace = io.read()
                if replace == g_inventory1 then
                  io.write("You replaced the "); io.write(replace); io.write(" with a sword.")
                  g_inventory1 = "a sword"
                elseif replace == g_inventory2 then
                  io.write("You replaced the "); io.write(replace); io.write(" with a sword.")
                  inventory2 = "a sword"
                elseif replace == g_inventory3 then
                  io.write("You replaced the "); io.write(replace); io.write(" with a sword.")
                  inventory3 = "a sword"
                elseif replace == "leave it" then
                  print("You leave the sword.")
                else
                  print("You randomly thought of a pointless word and moved on ahead.")
                end
            if lootdrop == 2 then
              print("A hatchet sticks out of a tree stump, and you take it out.")
              if inventory1 == nil then
                inventory1 = "a hatchet"
              elseif inventory2 == nil then
                inventory2 = "a hatchet"
              elseif inventory3 == nil then
                inventory3 = "a hatchet"
              else
                print("You don't have room for this hatchet. Replace items or 'leave it'? Items to replace:")
                  print(g_inventory1)
                  print(g_inventory2)
                  print(g_inventory3)
                  replace = io.read()
                  if replace == g_inventory1 then
                    io.write("You replaced the "); io.write(replace); io.write(" with the hatchet.")
                    g_inventory1 = "a hatchet"
                  elseif replace == g_inventory2 then
                    io.write("You replaced the "); io.write(replace); io.write(" with the hatchet.")
                    inventory2 = "a hatchet"
                  elseif replace == g_inventory3 then
                    io.write("You replaced the "); io.write(replace); io.write(" with the hatchet.")
                    inventory3 = "a hatchet"
                  elseif replace == "leave it" then
                    print("You leave the hatchet.")
                  else
                    print("You randomly thought of a pointless word and moved on ahead.")
                  end
               end
             if lootdrop == 3 then
              if g_inventory1 == nil then
                print("You have found a carving knife. You pick it up.")
                g_inventory1 = "a carving knife"
              elseif g_inventory2 == nil then
                print("You have found a carving knife. You pick it up.")
                g_inventory2 = "a carving knife"  
              elseif g_inventory3 == nil then
                print("You have found a carving knife. You pick it up.")
                g_inventory3 = "a carving knife"
              else
                print("You have no room for this carving knife. 'leave it' or replace an item? Items to replace:")
                print(g_inventory1)
                print(g_inventory2)
                print(g_inventory3)
                replace = io.read()
                if replace == g_inventory1 then
                  io.write("You replaced the "); io.write(inventory1); io.write(" with a carving knife.")
                  g_inventory1 = "a carving knife"
                elseif replace == g_inventory2 then
                  io.write("You replaced the "); io.write(inventory1); io.write(" with a carving knife.")
                  g_inventory2 = "a carving knife"
                elseif replace == g_inventory3 then
                  io.write("You replaced the "); io.write(inventory1); io.write(" with a carving knife.")
                  g_inventory3 = "a carving knife"
                elseif replace == "leave it" then
                  print("You leave the sword.")
                else
                  print("You think of a pointless word and move on ahead.")
                end
            if lootdrop == 4 then
              if g_inventory1 == nil then
              print("You have found a magical amulet. You pick it up.")
              g_inventory1 = "a magical amulet"
            elseif g_inventory2 == nil then
              print("You have found a magical amulet. You pick it up.")
              g_inventory2 = "a magical amulet"  
            elseif g_inventory3 == nil then
              print("You have found a carving knife. You pick it up.")
              g_inventory3 = "a magical amulet"
            else
              print("You have no room for this magical amulet. 'leave it' or replace an item? Items to replace:")
              print(g_inventory1)
              print(g_inventory2)
              print(g_inventory3)
              replace = io.read()
              if replace == g_inventory1 then
                io.write("You replaced the "); io.write(inventory1); io.write(" with a magical amulet.")
                g_inventory1 = "a magical amulet"
              elseif replace == g_inventory2 then
                io.write("You replaced the "); io.write(inventory1); io.write(" with a magical amulet.")
                g_inventory2 = "a magical amulet"
              elseif replace == g_inventory3 then
                io.write("You replaced the "); io.write(inventory1); io.write(" with a magical amulet.")
                g_inventory3 = "a magical amulet"
              elseif replace == "leave it" then
                print("You leave the amulet.")
              else
                print("You think of a pointless word and move on ahead.")   
            if lootdrop == 5 then
              print("You failed to find anything useful.")
              end
          elseif searchevent == 3 then
            print("You find nothing.")

Answer 1

I would separate the data from the navigation; have variables for a state. That way, as you expand your game, if you decide to change something about the interface, it's in one spot instead instead of mixed in with the data.

#!/usr/local/bin/lua

map = {
    ["peace"] = {
        title = "Peaceful",
        description = [[You find a leafy forest.]],
        exits = { danger = true },
        objects = { "tree" }
    },
    ["danger"] = {
        title = "Dangerous",
        description = [[You are on an erupting volcano with hot lava.]],
        exits = { peace = true, civil = true },
        objects = { "sword" }
    },
    ["civil"] = {
        title = "Civilized",
        description = [[You find yourself having tea in the countryside.]],
        exits = { danger = true },
        objects = {  }
    }
}

objects = {
    ["tree"] = {
        name = "tree",
        description = "A tree is here.",
        take = false
    },
    ["sword"] = {
        name = "sharp sword",
        description = "A sword is here.",
        take = "You found an abandoned sword. You pick it up."
    }
}

-- these are commands that the user enters
-- they take a list of words that are generated by split()
action = {
    ["exit"] = function(words)
        where = nil
    end,
    ["go"]   = function(words)
        local to = words[2]
        if(to == nil) then
            print("Go where?")
            return
        end
        if(map[where].exits[to] == true) then
            where = to
        else
            print("No exit to " .. to .. ".")
        end
    end,
    ["take"] = function(words)
        print("fixme: take has not been implemented")
    end,
    ["look"] = function(words)
        -- it refreshes the screen automatically anyway
    end
}

-- split by white space
function split(str)
    local words = {}
    local w = 1
    for s in str:gmatch("([%S]+)") do
        words[w] = s
        w = w + 1
    end
    return words
end

-- this is called in a loop; io.read is blocking for input
function navigate()
    -- describe state
    print(map[where].title .. "\n" .. map[where].description);
    for k,v in pairs(map[where].objects) do print(objects[v].description) end
    print("Exits:")
    for k,v in pairs(map[where].exits) do print(k) end

    -- input
    print("Where would you like to do?")
    local input = io.read("*line")
    local words = split(input)

    -- parse to command
    local act = action[words[1]]
    if act then
        act(words)
    else
        print("That is not a command; commands:")
        for k, v in pairs(action) do print(k) end
    end

end

-- starting state
where = "civil"
inventory = { }

-- main loop
while where do
    navigate();
    print("")
end

print("Goodbye.")

The state I used is contained in where and it's an index to the table map; when it goes nil, it exits the programme. Also inventory is a state list, but it is not used, yet. I used the tutorials at:

• https://www.lua.org/pil/11.html
• https://stackoverflow.com/questions/1426954/split-string-in-lua
• http://lua-users.org/wiki/SwitchStatement
• https://www.lua.org/pil/4.3.1.html
• https://coronalabs.com/blog/2014/09/02/tutorial-printing-table-contents/
• https://stackoverflow.com/questions/656199/search-for-an-item-in-a-lua-list