Enum ParserPredicate 

pub enum ParserPredicate {
    True,
    False,
    FalseWithMessage {
        message: &'static str,
    },
    Invoke {
        value: bool,
    },
    LookaheadTextEquals {
        offset: isize,
        text: &'static str,
    },
    LookaheadNotEquals {
        offset: isize,
        token_type: i32,
    },
    TokenPairAdjacent,
    ContextChildRuleTextNotEquals {
        rule_index: usize,
        text: &'static str,
    },
    LocalIntEquals {
        value: i64,
    },
    LocalIntLessOrEqual {
        value: i64,
    },
    MemberModuloEquals {
        member: usize,
        modulus: i64,
        value: i64,
        equals: bool,
    },
    MemberEquals {
        member: usize,
        value: i64,
        equals: bool,
    },
}

Parser semantic predicate rendered from a supported target template.

The metadata recognizer evaluates these at the token-stream index where the predicate transition is reached. Unsupported or absent predicate templates remain unconditional so existing generated parsers keep their previous behavior unless the generator opts into this table.

Variants

True

False

FalseWithMessage

Predicate that always fails and carries ANTLR’s <fail='...'> message.

Fields

message: &'static str

Invoke

Target-template test helper that reports predicate evaluation before returning the wrapped boolean value.

Fields

value: bool

LookaheadTextEquals

Fields

offset: isize

text: &'static str

LookaheadNotEquals

Fields

offset: isize

token_type: i32

TokenPairAdjacent

Checks that the last two consumed visible tokens were adjacent in the token stream. Used by C# parser predicates for split operator tokens.

ContextChildRuleTextNotEquals

Checks a generated parser context child by rule index and text.

If the child is absent the predicate succeeds, matching target helpers that treat incomplete or non-matching contexts as non-restrictive.

Fields

rule_index: usize

text: &'static str

LocalIntEquals

Compares the current rule invocation’s integer argument with a literal value from a supported ValEquals("$i", "...") target template.

Fields

value: i64

LocalIntLessOrEqual

Checks ANTLR-style raw predicates like 5 >= $_p against the current rule invocation’s integer argument.

Fields

value: i64

MemberModuloEquals

Compares a generated parser integer member modulo a literal value.

Fields

member: usize

modulus: i64

value: i64

equals: bool

MemberEquals

Compares a generated parser integer member with a literal value.

Fields

member: usize

value: i64

equals: bool

Implementations

impl ParserPredicate

pub fn lower_into_semir(self, ir: &mut SemIr) -> ExprId

Lowers the legacy predicate metadata variant into SemIR.

This is the compatibility adapter for generated parsers produced while the runtime still emitted closed enum tables. Newer generated parsers emit SemIR directly.

pub const fn failure_message(self) -> Option<&'static str>

Trait Implementations

impl Clone for ParserPredicate

fn clone(&self) -> ParserPredicate

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ParserPredicate

impl Debug for ParserPredicate

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

Formats the value using the given formatter.

impl Eq for ParserPredicate

impl Ord for ParserPredicate

fn cmp(&self, other: &ParserPredicate) -> 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 ParserPredicate

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for ParserPredicate

fn partial_cmp(&self, other: &ParserPredicate) -> 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 ParserPredicate