# Create a world
var world = World()

# Add an entity
let entityId = world.addEntity (
  Character(name: "Marcus", class: "Warrior"),
  Health(health: 120, maxHealth: 120)
)

# Get a component from an entity
for health in world.component(entityId, Health):
  health.health += 75

# Get multiple components from an entity
for (character, health) in world.component(entityId, (Character, Health)):
  character.name = "Happy " & character.name
  health.health += 75

# Query for components
var characterWithSwordsQuery = Query[(Character, Sword)]()
for (character, sword) in world.query(characterWithSwordsQuery):
  echo character.name, " has a sword, ", sword.name, "!"

# Removing an entity
world.removeEntity entityId

# Adding a component
world.addComponent(entityId, Shield(name: "Steel Shield", defense: 15))

# Removing a component
world.removeComponent(entityId, Shield)

# Using an Id component fills it with the Id of the entity
# This is useful for embedding references to other entities into components
let entityId = world.addEntity (Id(), Character(name: "Leon", class: "Paladin"))

for idComponent in world.component(entityId, Id):
  assert entityId == idComponent

# Query components for writting
var characterWithSwordsQuery = Query[(Character, Write[Health])]()
for (character, health) in world.query(characterWithSwordsQuery):
  health.health += 10

# Query for optional components
var characterWithSwordsQuery = Query[(Character, Opt[Weapon])]()
for (character, weapon) in world.query(characterWithSwordsQuery):
  weapon.isSmoething:
    echo character.name, " has a weapon, ", weapon.name
  weapon.isNothing:
    echo character.name, " has no weapon"

# Exclude components from a query
var disarmedCharacters = Query[(Character, Not[Weapon])]()
for (character,) in world.query(disarmedCharacters):
  echo character.name, " has no weapon"