Struct EnterRuleEvent 

#[non_exhaustive]
pub struct EnterRuleEvent<'a> {
    pub rule_index: usize,
    pub current: Option<TokenView<'a>>,
}

A rule-entry event delivered to ParseListener::enter_every_rule.

Non-exhaustive so future fields (alt number, invoking state, a context handle) extend the event without breaking implementors.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

rule_index: usize

Index of the rule being entered (compare against the generated RULE_* constants).

current: Option<TokenView<'a>>

The lookahead token the rule starts at — its line/column/offsets anchor listener diagnostics — or None at end of input.

Trait Implementations

impl<'a> Debug for EnterRuleEvent<'a>

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

Formats the value using the given formatter.