# Struct regex::RegexBuilder [−] [src]

    pub struct RegexBuilder(_);

A configurable builder for a regular expression.

A builder can be used to configure how the regex is built, for example, by setting the default flags (which can be overridden in the expression itself) or setting various limits.

## Methods

### `impl RegexBuilder`

#### `fn new(pattern: &str) -> RegexBuilder`

Create a new regular expression builder with the given pattern.

If the pattern is invalid, then an error will be returned when `compile` is called.

#### `fn compile(self) -> Result<Regex, Error>`

Consume the builder and compile the regular expression.

#### `fn case_insensitive(self, yes: bool) -> RegexBuilder`

Set the value for the case insensitive (`i`) flag.

#### `fn multi_line(self, yes: bool) -> RegexBuilder`

Set the value for the multi-line matching (`m`) flag.

#### `fn dot_matches_new_line(self, yes: bool) -> RegexBuilder`

Set the value for the any character (`s`) flag, where in `.` matches anything when `s` is set and matches anything except for new line when it is not set (the default).

N.B. "matches anything" means "any byte" for `regex::bytes::Regex` expressions and means "any Unicode codepoint" for `regex::Regex` expressions.

#### `fn swap_greed(self, yes: bool) -> RegexBuilder`

Set the value for the greedy swap (`U`) flag.

#### `fn ignore_whitespace(self, yes: bool) -> RegexBuilder`

Set the value for the ignore whitespace (`x`) flag.

#### `fn unicode(self, yes: bool) -> RegexBuilder`

Set the value for the Unicode (`u`) flag.

For byte based regular expressions, this is disabled by default.

#### `fn size_limit(self, limit: usize) -> RegexBuilder`

Set the approximate size limit of the compiled regular expression.

This roughly corresponds to the number of bytes occupied by a single compiled program. If the program exceeds this number, then a compilation error is returned.

#### `fn dfa_size_limit(self, limit: usize) -> RegexBuilder`

Set the approximate size of the cache used by the DFA.

This roughly corresponds to the number of bytes that the DFA will use while searching.

Note that this is a per thread limit. There is no way to set a global limit. In particular, if a regex is used from multiple threads simulanteously, then each thread may use up to the number of bytes specified here.

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