Enum EngineError 

#[non_exhaustive]
pub enum EngineError {
    EvaluationError(String),
    UnknownVariable(String),
    TypeError(String),
    DivisionByZero,
    UnknownFunction(String),
    FunctionError(String),
    UnknownRule(String),
    MaxCyclesExceeded(usize),
    Cancelled,
    TimedOut,
    InRule {
        rule: String,
        phase: RulePhase,
        source: Box<EngineError>,
    },
}

Errors from executing rules.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

EvaluationError(String)

An expression couldn’t be evaluated, e.g. a missing field.

UnknownVariable(String)

A rule referred to a fact that doesn’t exist.

TypeError(String)

An operation was applied to values of the wrong type.

DivisionByZero

Integer % by zero.

UnknownFunction(String)

A rule called a function that is neither built in nor registered.

FunctionError(String)

A function or method call failed (wrong arguments, or an error it returned).

UnknownRule(String)

Retract named a rule that doesn’t exist.

MaxCyclesExceeded(usize)

Rules kept firing past the cycle limit (see RuleEngine::set_max_cycles).

Cancelled

The execution’s cancellation flag was set.

TimedOut

The execution’s timeout elapsed.

InRule

An error raised while evaluating or executing a specific rule.

Fields

rule: String

The rule’s name.

phase: RulePhase

Whether the error came from the rule’s condition or its actions.

source: Box<EngineError>

The underlying error.

Implementations

impl EngineError

pub fn root(&self) -> &EngineError

The underlying error, without the rule it occurred in.

Trait Implementations

impl Debug for EngineError

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

Formats the value using the given formatter.

impl Display for EngineError

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

Formats the value using the given formatter.

impl Error for EngineError

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.