pub fn is_meta_character(c: char) -> bool
Expand description
Returns true if the given character has significance in a regex.
Generally speaking, these are the only characters which must be escaped
in order to match their literal meaning. For example, to match a literal
|
, one could write \|
. Sometimes escaping isn’t always necessary. For
example, -
is treated as a meta character because of its significance
for writing ranges inside of character classes, but the regex -
will
match a literal -
because -
has no special meaning outside of character
classes.
In order to determine whether a character may be escaped at all, the
is_escapeable_character
routine should be used. The difference between
is_meta_character
and is_escapeable_character
is that the latter will
return true for some characters that are not meta characters. For
example, %
and \%
both match a literal %
in all contexts. In other
words, is_escapeable_character
includes “superfluous” escapes.
Note that the set of characters for which this function returns true
or
false
is fixed and won’t change in a semver compatible release. (In this
case, “semver compatible release” actually refers to the regex
crate
itself, since reducing or expanding the set of meta characters would be a
breaking change for not just regex-syntax
but also regex
itself.)
§Example
use regex_syntax::is_meta_character;
assert!(is_meta_character('?'));
assert!(is_meta_character('-'));
assert!(is_meta_character('&'));
assert!(is_meta_character('#'));
assert!(!is_meta_character('%'));
assert!(!is_meta_character('/'));
assert!(!is_meta_character('!'));
assert!(!is_meta_character('"'));
assert!(!is_meta_character('e'));