//! Conditions (Module 11): `X ON Z IS P` gives an X the property P only while it is on a Z.
//!
//! The parser reads a condition into the rule (`Rule::conditions`); the engine never
//! decides it there. A condition is evaluated for one object, against the board as
//! it is, every time a rule is about to be used: by `Level::has_property` (and so by
//! movement, the hazards and the win check), and by conversion. What a condition
//! word means is a `ConditionCheck` that content provides, registered by word, as
//! movement responses and hazards are. The engine knows only that a word with role
//! `Condition` may stand between the subjects and `IS`.

use std::collections::HashMap;

use super::grid::ObjectId;
use super::level::Level;

/// Content's meaning for one condition word: does the condition, with these nouns
/// (in the order they are written), hold for object `id` on the board as it is now?
pub type ConditionCheck = fn(&Level, ObjectId, &[String]) -> bool;

/// Content's condition checks, by condition word: `{"ON": on}`.
pub type ConditionChecks = HashMap<String, ConditionCheck>;