Docs / Quick code

Libraries, data tables and object values

Sharing functions across a script and across the game, keeping game data in tables, and objects' starting values.

#Functions shared by a script

A function written at the top of one Code node can be called from every other Code node of the same script (on the same object). A good habit: one Code node at the side of the graph, not connected to anything, holding the script's helper functions.

#Libraries: functions for the whole game

Make a script (Scripts tab) — say Utils — and put functions in its Code nodes:

-- In the script "Utils":
function clamp_hp(n)
  return clamp(n, 0, 100)
end

function greet(name)
  popup("Welcome, " .. name .. "!")
end

Any code can then use it:

local u = require("Utils")
u.greet("Mira")
local hp = u.clamp_hp(140)    -- 100

• require finds the script by its name or id.
• Its Code nodes run once, all at once (no waiting), the first time it's required in a level; later requires give the same table.
• It gives the table the library returns, if it returns one — otherwise a table of the functions it defines.
• Libraries can require other libraries (not in a circle).

Returning a table makes a tidy module with its own settings:

-- In the script "Combat":
local M = {crit_chance = 15}

function M.damage(base)
  if chance(M.crit_chance) then return base * 2 end
  return base
end

return M

#Data tables

The Data tab holds spreadsheet-like tables of game data — enemy stats, loot drops, shop prices, lines of text — so numbers live in one place instead of inside code. Each row's first column is its key; cells are numbers, text or true / false (typed as they look).

local enemies = data("Enemies")
local g = enemies["Goblin"]
self.hp = g.hp                 -- 10

for name, row in data("Enemies") do
  print(name .. ": " .. row.hp .. " hp")
end

data(name) gives nil when there's no table with that name (or id). Data tables are part of the project, so they're in exported games too.

#Objects' starting values

Select an object, then Properties ▸ Values for code — one per line:

hp = 10
loot = ["Coin", "Gem"]
angry = false

Code reads them as the object's own values (self.hp, object("name").loot) and can change them while the game runs; the changes are saved with the game. Two copies of the same model can start differently. See Objects.