Trait Knob 

pub trait Knob<S> {
    // Required methods
    fn name(&self) -> &str;
    fn range(&self) -> RangeInclusive<i32> ;
    fn apply(&self, stage: &S, step: i32) -> Option<S>;
    fn describe(&self, step: i32) -> String;

    // Provided method
    fn stride(&self) -> u32 { ... }
}

One way the game lets the search change a stage definition S: a bounded integer step, 0 being the stage as authored.

Required Methods

fn name(&self) -> &str

Its name, which the change set uses.

fn range(&self) -> RangeInclusive<i32>

The steps it may take. It holds 0, the stage as authored.

fn apply(&self, stage: &S, step: i32) -> Option<S>

stage with this knob moved step, or None when it can’t apply there (no free tile for one more piece). Knobs apply in the order given, each to the result of the one before; a knob at 0 isn’t applied.

fn describe(&self, step: i32) -> String

The change of step in plain words, such as "the foe trips 10% less often".

Provided Methods

fn stride(&self) -> u32

The first step size the search tries: a coarse knob (every enemy’s level) starts larger. The search halves it down to 1.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors