Targeting

Targeting is a fundamental mechanic in Magic: The Gathering that determines which game objects (cards, players, etc.) will be affected by a spell or ability. This document outlines how targeting is implemented in Rummage.

Core Concepts

Target Types

The targeting system supports various target types:

Cards: Cards in any zone
Players: Players in the game
Tokens: Token creatures on the battlefield
Spells: Spells on the stack
Emblems: Persistent effects in the command zone
Abilities: Abilities on the stack

Target Restrictions

Targets can be restricted based on:

Characteristics: Card type, subtypes, color, power/toughness, etc.
Game State: Tapped/untapped, controller, zone, etc.
Custom Conditions: Any programmable condition

Implementation

Target Selection

Target selection is implemented using queries and predicates:

#![allow(unused)]
fn main() {
// Example of a targeting predicate for "target creature you control"
pub fn creature_you_control_predicate(
    entity: Entity,
    world: &World,
    source_player: Entity,
) -> bool {
    let card_type = world.get::<CardType>(entity);
    let controller = world.get::<Controller>(entity);
    let zone = world.get::<Zone>(entity);
    
    matches!(card_type, Ok(CardType::Creature)) &&
    matches!(controller, Ok(Controller(player)) if *player == source_player) &&
    matches!(zone, Ok(Zone::Battlefield))
}
}