regex_automata::dfa::dense

Struct BuildError

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pub struct BuildError { /* private fields */ }
Available on (crate features dfa-search or dfa-onepass) and crate feature dfa-search and crate feature dfa-build only.
Expand description

An error that occurred during the construction of a DFA.

This error does not provide many introspection capabilities. There are generally only two things you can do with it:

  • Obtain a human readable message via its std::fmt::Display impl.
  • Access an underlying nfa::thompson::BuildError type from its source method via the std::error::Error trait. This error only occurs when using convenience routines for building a DFA directly from a pattern string.

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

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impl BuildError

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pub fn is_size_limit_exceeded(&self) -> bool

Returns true if and only if this error corresponds to an error with DFA construction that occurred because of exceeding a size limit.

While this can occur when size limits like Config::dfa_size_limit or Config::determinize_size_limit are exceeded, this can also occur when the number of states or patterns exceeds a hard-coded maximum. (Where these maximums are derived based on the values representable by StateID and PatternID.)

This predicate is useful in contexts where you want to distinguish between errors related to something provided by an end user (for example, an invalid regex pattern) and errors related to configured heuristics. For example, building a DFA might be an optimization that you want to skip if construction fails because of an exceeded size limit, but where you want to bubble up an error if it fails for some other reason.

§Example
use regex_automata::{dfa::{dense, Automaton}, Input};

let err = dense::Builder::new()
    .configure(dense::Config::new()
        .determinize_size_limit(Some(100_000))
    )
    .build(r"\w{20}")
    .unwrap_err();
// This error occurs because a size limit was exceeded.
// But things are otherwise valid.
assert!(err.is_size_limit_exceeded());

let err = dense::Builder::new()
    .build(r"\bxyz\b")
    .unwrap_err();
// This error occurs because a Unicode word boundary
// was used without enabling heuristic support for it.
// So... not related to size limits.
assert!(!err.is_size_limit_exceeded());

let err = dense::Builder::new()
    .build(r"(xyz")
    .unwrap_err();
// This error occurs because the pattern is invalid.
// So... not related to size limits.
assert!(!err.is_size_limit_exceeded());

Trait Implementations§

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impl Clone for BuildError

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fn clone(&self) -> BuildError

Returns a copy of the value. Read more
1.0.0 · Source§

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

Performs copy-assignment from source. Read more
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impl Debug for BuildError

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

Formats the value using the given formatter. Read more
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impl Display for BuildError

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

Formats the value using the given formatter. Read more
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impl Error for BuildError

Available on crate feature std only.
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fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
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fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
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fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.