Struct Rule 

pub struct Rule {
    pub origin: String,
    pub origin_id: NontermId,
    pub expansion: Vec<Symbol>,
    pub alias: Option<String>,
    pub order: i64,
    pub expand1: bool,
    pub priority: Option<i32>,
    pub keep_all_tokens: bool,
    pub empty_indices: Vec<bool>,
    pub display_id: DisplayId,
    pub shape: RuleShape,
}

A grammar rule. Lark’s RuleOptions fields are flattened onto the rule (keep flattened): a rule with multiple BNF expansions would otherwise SHARE one options object, which is exactly the aliasing that makes Lark’s priority='invert' negate a multi-expansion rule once per expansion (a net no-op — see the tp_prio_plus_invert note in the conformance corpus). Owning the fields by value makes that class of bug unrepresentable.

Flat storage, not a flat parameter list: in-crate construction goes through Rule::build from a RuleDraft rather than threading the fields one by one.

The raw keep_all_tokens is retained: AmbiguousExpander needs it and it is not reconstructible from RuleShape::to_include.

Fields

origin: String

origin_id: NontermId

The origin nonterminal’s id — a goto_actions COLUMN index (the LHS nonterminal a reduce gotos on), NOT a rule index. The rules[] index space is RuleId.

expansion: Vec<Symbol>

alias: Option<String>

order: i64

expand1: bool

priority: Option<i32>

Rule priority (rule.3:); None when undeclared. Earley ambiguity resolution consumes it.

keep_all_tokens: bool

empty_indices: Vec<bool>

Lark’s maybe_placeholders encoding: true at logical position i = “insert a placeholder here at reduce time”.

display_id: DisplayId

Index into ParseTable::display_names (origin, or alias when present).

shape: RuleShape

Precomputed reduce-time shaping (built by build_rule_shape).

Trait Implementations

impl Clone for Rule

fn clone(&self) -> Rule

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Rule

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

Formats the value using the given formatter.

impl Eq for Rule

impl PartialEq for Rule

fn eq(&self, other: &Rule) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Rule