Struct regex_automata::meta::BuildError

pub struct BuildError { /* private fields */ }

An error that occurs when construction of a Regex fails.

A build error is generally a result of one of two possible failure modes. First is a parse or syntax error in the concrete syntax of a pattern. Second is that the construction of the underlying regex matcher fails, usually because it gets too big with respect to limits like Config::nfa_size_limit.

This error provides very little introspection capabilities. You can:

• Ask for the PatternID of the pattern that caused an error, if one is available. This is available for things like syntax errors, but not for cases where build limits are exceeded.
• Ask for the underlying syntax error, but only if the error is a syntax error.
• Ask for a human readable message corresponding to the underlying error.
• The BuildError::source method (from the std::error::Error trait implementation) may be used to query for an underlying error if one exists. There are no API guarantees about which error is returned.

When the std feature is enabled, this implements std::error::Error.

Implementations

impl BuildError

pub fn pattern(&self) -> Option<PatternID>

If it is known which pattern ID caused this build error to occur, then this method returns it.

Some errors are not associated with a particular pattern. However, any errors that occur as part of parsing a pattern are guaranteed to be associated with a pattern ID.

Example

use regex_automata::{meta::Regex, PatternID};

let err = Regex::new_many(&["a", "b", r"\p{Foo}", "c"]).unwrap_err();
assert_eq!(Some(PatternID::must(2)), err.pattern());

pub fn size_limit(&self) -> Option<usize>

If this error occurred because the regex exceeded the configured size limit before being built, then this returns the configured size limit.

The limit returned is what was configured, and corresponds to the maximum amount of heap usage in bytes.

pub fn syntax_error(&self) -> Option<&Error>

If this error corresponds to a syntax error, then a reference to it is returned by this method.

Trait Implementations

impl Clone for BuildError

fn clone(&self) -> BuildError

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for BuildError

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

Formats the value using the given formatter.

impl Display for BuildError

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

Formats the value using the given formatter.

impl Error for BuildError

fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, demand: &mut Demand<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type based access to context intended for error reports.