Enum HirKind

pub enum HirKind {
    Empty,
    Literal(Literal),
    Class(Class),
    Look(Look),
    Repetition(Repetition),
    Capture(Capture),
    Concat(Vec<Hir>),
    Alternation(Vec<Hir>),
}

The underlying kind of an arbitrary Hir expression.

An HirKind is principally useful for doing case analysis on the type of a regular expression. If you’re looking to build new Hir values, then you must use the smart constructors defined on Hir, like Hir::repetition, to build new Hir values. The API intentionally does not expose any way of building an Hir directly from an HirKind.

Variants

Empty

The empty regular expression, which matches everything, including the empty string.

Literal(Literal)

A literalstring that matches exactly these bytes.

Class(Class)

A single character class that matches any of the characters in the class. A class can either consist of Unicode scalar values as characters, or it can use bytes.

A class may be empty. In which case, it matches nothing.

Look(Look)

A look-around assertion. A look-around match always has zero length.

Repetition(Repetition)

A repetition operation applied to a sub-expression.

Capture(Capture)

A capturing group, which contains a sub-expression.

Concat(Vec<Hir>)

A concatenation of expressions.

A concatenation matches only if each of its sub-expressions match one after the other.

Concatenations are guaranteed by Hir’s smart constructors to always have at least two sub-expressions.

Alternation(Vec<Hir>)

An alternation of expressions.

An alternation matches only if at least one of its sub-expressions match. If multiple sub-expressions match, then the leftmost is preferred.

Alternations are guaranteed by Hir’s smart constructors to always have at least two sub-expressions.

Implementations

impl HirKind

pub fn subs(&self) -> &[Hir]

Returns a slice of this kind’s sub-expressions, if any.

Trait Implementations

impl Clone for HirKind

fn clone(&self) -> HirKind

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for HirKind

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

Formats the value using the given formatter.

impl PartialEq for HirKind

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for HirKind

impl StructuralPartialEq for HirKind

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 40 bytes

Size for each variant:

• Empty: 0 bytes
• Literal: 24 bytes
• Class: 40 bytes
• Look: 12 bytes
• Repetition: 32 bytes
• Capture: 40 bytes
• Concat: 32 bytes
• Alternation: 32 bytes