Struct MemberEnv 

pub struct MemberEnv { /* private fields */ }

Grammar-declared member state: numbered scalar and stack slots.

Recognition threads this by value along each speculative path (it is part of the parser’s memo key), so it is ordered and compares structurally. Absent slots are not stored: a slot holding 0 is distinct from one never written, but an emptied stack is canonicalized back to absent so two logically identical paths stay Eq — and keep sharing memo entries.

Scalar and stack slot numbers live in separate namespaces; the generator assigns each declared member to one or the other.

Implementations

impl MemberEnv

pub const fn new() -> Self

pub fn with_initial_scalars( initial: impl IntoIterator<Item = (usize, i64)>, ) -> Self

Builds an environment holding a grammar’s declared initial scalar values.

Grammars write private bool verbatium = true; / private int level = 1;. Those initializers are part of the grammar’s meaning: a predicate reading a slot that silently started at 0 instead would reject input the source grammar accepts. Generated recognizers seed with this so a fresh recognizer — and every Self::reset_to_initial afterwards — starts where the grammar says.

pub fn reset_to_initial( &mut self, initial: impl IntoIterator<Item = (usize, i64)>, )

Clears all state back to the declared initial scalar values.

This is what a recognizer reset needs: not “empty”, but the state a freshly constructed recognizer had. Stacks always reset to empty, since a declaration cannot pre-seed one.

pub fn is_empty(&self) -> bool

Whether no slot has been written.

pub fn scalar(&self, member: usize) -> Option<i64>

Reads a scalar slot; None when never written.

pub fn set_scalar(&mut self, member: usize, value: i64)

Writes a scalar slot.

pub fn add_scalar(&mut self, member: usize, delta: i64) -> i64

Adds to a scalar slot (absent reads as 0) and returns the new value.

pub fn stack_top(&self, member: usize) -> Option<i64>

Top of a stack slot; None when empty or never pushed.

pub fn stack_len(&self, member: usize) -> usize

Depth of a stack slot; 0 when never pushed.

pub fn push_stack(&mut self, member: usize, value: i64)

Pushes onto a stack slot.

pub fn pop_stack(&mut self, member: usize) -> Option<i64>

Pops a stack slot, returning the removed value, or None when empty.

An emptied stack drops its slot so it compares equal to one never pushed — otherwise push-then-pop would produce a memo key that no longer matches the equivalent untouched path.

pub fn scalars(&self) -> impl Iterator<Item = (usize, i64)> + '_

Iterates written scalar slots in slot order.

Trait Implementations

impl Clone for MemberEnv

fn clone(&self) -> MemberEnv

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MemberEnv

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

Formats the value using the given formatter.

impl Default for MemberEnv

fn default() -> MemberEnv

Returns the “default value” for a type.

impl Eq for MemberEnv

impl Ord for MemberEnv

fn cmp(&self, other: &MemberEnv) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for MemberEnv

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for MemberEnv

fn partial_cmp(&self, other: &MemberEnv) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for MemberEnv