Struct Lock 

pub struct Lock {
    pub tiers: BTreeMap<String, Tier>,
}

The persisted previous solution — §3.4’s stability guardrail.

A one-line edit must not re-place unrelated code. Nothing in the cost model prevents that on its own: costs are a function of the whole program, so a new definition shifts them everywhere. The lock is what turns “the solver happens to agree with yesterday” into “the solver is asked to agree with yesterday, and says so when it cannot” — a tie-break and a record, never an override, because a lock that could force an illegal placement would be a way to defeat §3.5.

Fields

tiers: BTreeMap<String, Tier>

Implementations

impl Lock

pub const FILE: &'static str = "beck.lock"

pub fn from_json(text: &str) -> Option<Lock>

pub fn to_json(&self) -> String

pub fn of(solution: &Solution) -> Lock

Trait Implementations

impl Clone for Lock

fn clone(&self) -> Lock

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Lock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Lock

fn default() -> Lock

Returns the “default value” for a type.