Struct RE

pub struct RE {
    pub nullable: bool,
    /* private fields */
}

Regular expression structure

A regular expression includes an expression of type BaseRegLan, which is an abstract syntax tree.

In addition, each regular expression e has a unique integer id and three attributes:

• e.nullable is true if the language of e contains the empty string
• e.singleton is true if the language of e contains a single string
• e.deriv_class is the list of derivative classes of e.

The derivative classes are disjoint interval characters that cover a subset of the alphabet, and a complementary class that covers the rest. See CharPartition. The deriv_class partition is constructed to ensure that all the characters in a class produce the same derivative of e: if c1 and c2 are in the same derivative class of e then deriv(e, c1) and deriv(e, c2) are equal.

Operations on regular expressions use hash-consing and are performed with an ReManager.

Fields

nullable: bool

Whether the language contains the empty string

Implementations

impl RE

pub fn empty_complement(&self) -> bool

check whether the complementary class is empty

pub fn num_deriv_classes(&self) -> usize

number of derivative classes (not including the complementary class)

pub fn valid_class_id(&self, cid: ClassId) -> bool

check whether cid is a valid class id

pub fn is_empty(&self) -> bool

Check whether this RE is equal to the empty RE

pub fn class_ids(&self) -> ClassIdIterator<'_>

iterator to go through valid classIds

pub fn char_ranges(&self) -> impl Iterator<Item = &CharSet>

iterator to go through the intervals in an RE derivative classes

pub fn included_in(&self, other: &Self) -> bool

incomplete check for inclusion

• if this returns true then self is included in other
• otherwise, we don’t know

Trait Implementations

impl Debug for RE

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

Formats the value using the given formatter.

impl Display for RE

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

Formats the value using the given formatter.

impl Hash for RE

The hash code of an RE is just the hash code of its id.

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for RE

fn cmp(&self, other: &Self) -> 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 RE

Equality on RE is derived from the unique ids.

Two REs are equal iff they have the same id.

fn eq(&self, other: &Self) -> 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 PartialOrd for RE

Ordering on REs is based on unique ids.

We have re1 < re2 iff re1.id < re2.id

fn partial_cmp(&self, other: &Self) -> 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 Eq for RE