Enum nom::Err

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pub enum Err<E> {
    Incomplete(Needed),
    Error(E),
    Failure(E),
}
Expand description

The Err enum indicates the parser was not successful

It has three cases:

  • Incomplete indicates that more data is needed to decide. The Needed enum can contain how many additional bytes are necessary. If you are sure your parser is working on full data, you can wrap your parser with the complete combinator to transform that case in Error
  • Error means some parser did not succeed, but another one might (as an example, when testing different branches of an alt combinator)
  • Failure indicates an unrecoverable error. As an example, if you recognize a prefix to decide on the next parser to apply, and that parser fails, you know there’s no need to try other parsers, you were already in the right branch, so the data is invalid

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Incomplete(Needed)

There was not enough data

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Error(E)

The parser had an error (recoverable)

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Failure(E)

The parser had an unrecoverable error: we got to the right branch and we know other branches won’t work, so backtrack as fast as possible

Implementations§

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impl<E> Err<E>

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pub fn is_incomplete(&self) -> bool

Tests if the result is Incomplete

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pub fn map<E2, F>(self, f: F) -> Err<E2>
where F: FnOnce(E) -> E2,

Applies the given function to the inner error

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pub fn convert<F>(e: Err<F>) -> Self
where E: From<F>,

Automatically converts between errors if the underlying type supports it

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impl<T> Err<(T, ErrorKind)>

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pub fn map_input<U, F>(self, f: F) -> Err<(U, ErrorKind)>
where F: FnOnce(T) -> U,

Maps Err<(T, ErrorKind)> to Err<(U, ErrorKind)> with the given F: T -> U

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impl<T> Err<Error<T>>

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pub fn map_input<U, F>(self, f: F) -> Err<Error<U>>
where F: FnOnce(T) -> U,

Maps Err<error::Error<T>> to Err<error::Error<U>> with the given F: T -> U

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impl Err<(&[u8], ErrorKind)>

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pub fn to_owned(self) -> Err<(Vec<u8>, ErrorKind)>

Obtaining ownership

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impl Err<(&str, ErrorKind)>

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pub fn to_owned(self) -> Err<(String, ErrorKind)>

Obtaining ownership

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impl Err<Error<&[u8]>>

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pub fn to_owned(self) -> Err<Error<Vec<u8>>>

Obtaining ownership

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impl Err<Error<&str>>

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pub fn to_owned(self) -> Err<Error<String>>

Obtaining ownership

Trait Implementations§

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impl<E: Clone> Clone for Err<E>

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fn clone(&self) -> Err<E>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<E: Debug> Debug for Err<E>

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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<E> Display for Err<E>
where E: Debug,

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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<E> Error for Err<E>
where E: Debug,

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

The lower-level source of this error, if any. Read more
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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<E: PartialEq> PartialEq for Err<E>

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fn eq(&self, other: &Err<E>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<E: Eq> Eq for Err<E>

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impl<E> StructuralPartialEq for Err<E>

Auto Trait Implementations§

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impl<E> Freeze for Err<E>
where E: Freeze,

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impl<E> RefUnwindSafe for Err<E>
where E: RefUnwindSafe,

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impl<E> Send for Err<E>
where E: Send,

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impl<E> Sync for Err<E>
where E: Sync,

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impl<E> Unpin for Err<E>
where E: Unpin,

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impl<E> UnwindSafe for Err<E>
where E: UnwindSafe,

Blanket Implementations§

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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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default 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.