Struct LookSet

pub struct LookSet {
    pub bits: u32,
}

LookSet is a memory-efficient set of look-around assertions.

This is useful for efficiently tracking look-around assertions. For example, a thompson::NFA provides properties that return LookSets.

Fields

bits: u32

The underlying representation this set is exposed to make it possible to store it somewhere efficiently. The representation is that of a bitset, where each assertion occupies bit i where i = Look::as_repr().

Note that users of this internal representation must permit the full range of u16 values to be represented. For example, even if the current implementation only makes use of the 10 least significant bits, it may use more bits in a future semver compatible release.

Implementations

impl LookSet

pub fn empty() -> LookSet

Create an empty set of look-around assertions.

pub fn full() -> LookSet

Create a full set of look-around assertions.

This set contains all possible look-around assertions.

pub fn singleton(look: Look) -> LookSet

Create a look-around set containing the look-around assertion given.

This is a convenience routine for creating an empty set and inserting one look-around assertions.

pub fn len(self) -> usize

Returns the total number of look-around assertions in this set.

pub fn is_empty(self) -> bool

Returns true if and only if this set is empty.

pub fn contains(self, look: Look) -> bool

Returns true if and only if the given look-around assertion is in this set.

pub fn contains_anchor(&self) -> bool

Returns true if and only if this set contains any anchor assertions. This includes both “start/end of haystack” and “start/end of line.”

pub fn contains_anchor_haystack(&self) -> bool

Returns true if and only if this set contains any “start/end of haystack” anchors. This doesn’t include “start/end of line” anchors.

pub fn contains_anchor_line(&self) -> bool

Returns true if and only if this set contains any “start/end of line” anchors. This doesn’t include “start/end of haystack” anchors. This includes both \n line anchors and CRLF (\r\n) aware line anchors.

pub fn contains_anchor_lf(&self) -> bool

Returns true if and only if this set contains any “start/end of line” anchors that only treat \n as line terminators. This does not include haystack anchors or CRLF aware line anchors.

pub fn contains_anchor_crlf(&self) -> bool

Returns true if and only if this set contains any “start/end of line” anchors that are CRLF-aware. This doesn’t include “start/end of haystack” or “start/end of line-feed” anchors.

pub fn contains_word(self) -> bool

Returns true if and only if this set contains any word boundary or negated word boundary assertions. This include both Unicode and ASCII word boundaries.

pub fn contains_word_unicode(self) -> bool

Returns true if and only if this set contains any Unicode word boundary or negated Unicode word boundary assertions.

pub fn contains_word_ascii(self) -> bool

Returns true if and only if this set contains any ASCII word boundary or negated ASCII word boundary assertions.

pub fn iter(self) -> LookSetIter

Returns an iterator over all of the look-around assertions in this set.

pub fn insert(self, look: Look) -> LookSet

Return a new set that is equivalent to the original, but with the given assertion added to it. If the assertion is already in the set, then the returned set is equivalent to the original.

pub fn set_insert(&mut self, look: Look)

Updates this set in place with the result of inserting the given assertion into this set.

pub fn remove(self, look: Look) -> LookSet

Return a new set that is equivalent to the original, but with the given assertion removed from it. If the assertion is not in the set, then the returned set is equivalent to the original.

pub fn set_remove(&mut self, look: Look)

Updates this set in place with the result of removing the given assertion from this set.

pub fn subtract(self, other: LookSet) -> LookSet

Returns a new set that is the result of subtracting the given set from this set.

pub fn set_subtract(&mut self, other: LookSet)

Updates this set in place with the result of subtracting the given set from this set.

pub fn union(self, other: LookSet) -> LookSet

Returns a new set that is the union of this and the one given.

pub fn set_union(&mut self, other: LookSet)

Updates this set in place with the result of unioning it with the one given.

pub fn intersect(self, other: LookSet) -> LookSet

Returns a new set that is the intersection of this and the one given.

pub fn set_intersect(&mut self, other: LookSet)

Updates this set in place with the result of intersecting it with the one given.

pub fn read_repr(slice: &[u8]) -> LookSet

Return a LookSet from the slice given as a native endian 32-bit integer.

Panics

This panics if slice.len() < 4.

pub fn write_repr(self, slice: &mut [u8])

Write a LookSet as a native endian 32-bit integer to the beginning of the slice given.

Panics

This panics if slice.len() < 4.

pub fn available(self) -> Result<(), UnicodeWordBoundaryError>

Checks that all assertions in this set can be matched.

Some assertions, such as Unicode word boundaries, require optional (but enabled by default) tables that may not be available. If there are assertions in this set that require tables that are not available, then this will return an error.

Specifically, this returns an error when the the unicode-word-boundary feature is not enabled and this set contains a Unicode word boundary assertion.

It can be useful to use this on the result of NFA::look_set_any when building a matcher engine to ensure methods like LookMatcher::matches_set do not panic at search time.

Trait Implementations

impl Clone for LookSet

fn clone(&self) -> LookSet

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LookSet

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

Formats the value using the given formatter.

impl Default for LookSet

fn default() -> LookSet

Returns the “default value” for a type.

impl PartialEq for LookSet

fn eq(&self, other: &LookSet) -> 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 Copy for LookSet

impl Eq for LookSet

impl StructuralPartialEq for LookSet