Enum ReadError 

pub enum ReadError {
    Parse(ParseError),
    NotASingleQuery {
        count: usize,
    },
    NotAQuery,
    UnsupportedPredicate {
        predicate: &'static str,
    },
    InvalidPredicate {
        keyword: &'static str,
        reason: String,
    },
    InvalidKind {
        got: String,
    },
    IncompatiblePredicates {
        predicate: &'static str,
        kind: KindFilter,
    },
}

Read-path error family. Every variant means the query did not execute; no state was observed or mutated.

Variants

Parse(ParseError)

Parse failure on the query input.

NotASingleQuery

Input was not a single (query ...) form — the read API expects exactly one query per call.

Fields

count: usize

Number of forms parsed.

NotAQuery

Input parsed as something other than a (query ...) form.

UnsupportedPredicate

Parsed but includes a predicate whose behavior hasn’t been wired yet. 7.1 scope note: see the module docstring.

Fields

predicate: &'static str

Predicate keyword (e.g. "in_episode").

InvalidPredicate

A predicate’s value had the wrong shape for its keyword (e.g. :limit @not_a_number).

Fields

keyword: &'static str

Predicate keyword.

reason: String

Human-readable reason.

InvalidKind

:kind was provided with a value that isn’t one of the four canonical kinds.

Fields

got: String

The literal bareword supplied.

IncompatiblePredicates

A predicate was combined with a :kind value it doesn’t apply to — e.g. :s @alice :kind pro. Per read-protocol.md § 4.1 the :s / :p predicates are SEM / INF only; silently returning no records on this input would violate spec invariant § 13 #9 “no silent information loss,” so v1 rejects with a typed error.

Fields

predicate: &'static str

The offending predicate keyword.

kind: KindFilter

The :kind value it was combined with.

Trait Implementations

impl Debug for ReadError

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

Formats the value using the given formatter.

impl Display for ReadError

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

Formats the value using the given formatter.

impl Error for ReadError

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

Returns 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, 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.

impl From<ParseError> for ReadError

fn from(source: ParseError) -> Self

Converts to this type from the input type.

impl PartialEq for ReadError

fn eq(&self, other: &ReadError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ReadError