pub enum Look {
Show 18 variants
Start = 1,
End = 2,
StartLF = 4,
EndLF = 8,
StartCRLF = 16,
EndCRLF = 32,
WordAscii = 64,
WordAsciiNegate = 128,
WordUnicode = 256,
WordUnicodeNegate = 512,
WordStartAscii = 1_024,
WordEndAscii = 2_048,
WordStartUnicode = 4_096,
WordEndUnicode = 8_192,
WordStartHalfAscii = 16_384,
WordEndHalfAscii = 32_768,
WordStartHalfUnicode = 65_536,
WordEndHalfUnicode = 131_072,
}
Expand description
The high-level intermediate representation for a look-around assertion.
An assertion match is always zero-length. Also called an “empty match.”
Variants§
Start = 1
Match the beginning of text. Specifically, this matches at the starting position of the input.
End = 2
Match the end of text. Specifically, this matches at the ending position of the input.
StartLF = 4
Match the beginning of a line or the beginning of text. Specifically,
this matches at the starting position of the input, or at the position
immediately following a \n
character.
EndLF = 8
Match the end of a line or the end of text. Specifically, this matches
at the end position of the input, or at the position immediately
preceding a \n
character.
StartCRLF = 16
Match the beginning of a line or the beginning of text. Specifically,
this matches at the starting position of the input, or at the position
immediately following either a \r
or \n
character, but never after
a \r
when a \n
follows.
EndCRLF = 32
Match the end of a line or the end of text. Specifically, this matches
at the end position of the input, or at the position immediately
preceding a \r
or \n
character, but never before a \n
when a \r
precedes it.
WordAscii = 64
Match an ASCII-only word boundary. That is, this matches a position where the left adjacent character and right adjacent character correspond to a word and non-word or a non-word and word character.
WordAsciiNegate = 128
Match an ASCII-only negation of a word boundary.
WordUnicode = 256
Match a Unicode-aware word boundary. That is, this matches a position where the left adjacent character and right adjacent character correspond to a word and non-word or a non-word and word character.
WordUnicodeNegate = 512
Match a Unicode-aware negation of a word boundary.
WordStartAscii = 1_024
Match the start of an ASCII-only word boundary. That is, this matches a position at either the beginning of the haystack or where the previous character is not a word character and the following character is a word character.
WordEndAscii = 2_048
Match the end of an ASCII-only word boundary. That is, this matches a position at either the end of the haystack or where the previous character is a word character and the following character is not a word character.
WordStartUnicode = 4_096
Match the start of a Unicode word boundary. That is, this matches a position at either the beginning of the haystack or where the previous character is not a word character and the following character is a word character.
WordEndUnicode = 8_192
Match the end of a Unicode word boundary. That is, this matches a position at either the end of the haystack or where the previous character is a word character and the following character is not a word character.
WordStartHalfAscii = 16_384
Match the start half of an ASCII-only word boundary. That is, this matches a position at either the beginning of the haystack or where the previous character is not a word character.
WordEndHalfAscii = 32_768
Match the end half of an ASCII-only word boundary. That is, this matches a position at either the end of the haystack or where the following character is not a word character.
WordStartHalfUnicode = 65_536
Match the start half of a Unicode word boundary. That is, this matches a position at either the beginning of the haystack or where the previous character is not a word character.
WordEndHalfUnicode = 131_072
Match the end half of a Unicode word boundary. That is, this matches a position at either the end of the haystack or where the following character is not a word character.
Implementations§
Source§impl Look
impl Look
Sourcepub const fn reversed(self) -> Look
pub const fn reversed(self) -> Look
Flip the look-around assertion to its equivalent for reverse searches.
For example, StartLF
gets translated to EndLF
.
Some assertions, such as WordUnicode
, remain the same since they
match the same positions regardless of the direction of the search.
Sourcepub const fn as_repr(self) -> u32
pub const fn as_repr(self) -> u32
Return the underlying representation of this look-around enumeration
as an integer. Giving the return value to the Look::from_repr
constructor is guaranteed to return the same look-around variant that
one started with within a semver compatible release of this crate.
Sourcepub const fn from_repr(repr: u32) -> Option<Look>
pub const fn from_repr(repr: u32) -> Option<Look>
Given the underlying representation of a Look
value, return the
corresponding Look
value if the representation is valid. Otherwise
None
is returned.
Sourcepub const fn as_char(self) -> char
pub const fn as_char(self) -> char
Returns a convenient single codepoint representation of this look-around assertion. Each assertion is guaranteed to be represented by a distinct character.
This is useful for succinctly representing a look-around assertion in human friendly but succinct output intended for a programmer working on regex internals.
Trait Implementations§
impl Copy for Look
impl Eq for Look
impl StructuralPartialEq for Look
Auto Trait Implementations§
impl Freeze for Look
impl RefUnwindSafe for Look
impl Send for Look
impl Sync for Look
impl Unpin for Look
impl UnwindSafe for Look
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)