Tips and Tricks

A handful of habits that make everyday Concord code shorter and harder to get wrong. None of this is required.

Method chaining

give, ensure, remove, assemble, and destroy all return the Entity. Spawn in one expression when the recipe is obvious:

world:newEntity()
  :give("position", 50, 50)
  :give("terrestrial")

Stop chaining when a step needs a comment, a branch, or a name you will use again. A local Cat you can print is worth more than a clever one-liner.

Direct field access

Once a Component is given, it is a field:

print(Cat.position.x, Cat.position.y)

if Cat.terrestrial then
  print("Walks!")
end

Entity:has and Entity:get exist for when the name is in a variable, or when a typo should be an error instead of nil. Day-to-day game code uses the field.

Entity:getComponents is a shallow copy for inspection. Mutating a Component you got that way still mutates the Entity. It is not a clone.

Utils

Utils.shallowCopy copies keys from one table onto another. Nested tables are shared, not cloned. Concord uses it internally for serialize and for the “copy this class onto the instance” optimization. You may want it when you are writing your own serialize. You usually do not want it as a substitute for Cloning a Component.

Utils.loadNamespace belongs to its own article: Loading Namespaces.

See also

• Entities Guide
• Making a game with Concord and LÖVE