Enum Problem 

#[non_exhaustive]
pub enum Problem {
    ParseError,
    SqrtNegative,
    DivideByZero,
    NotFound,
    InsufficientParameters,
    NotANumber,
    Infinity,
    BadFraction,
    BadDecimal,
    BadInteger,
    OutOfRange,
    NotAnInteger,
    Exhausted,
    UnknownZero,
}

Problems when either parsing or attempting Arithmetic with Real numbers or when trying to make or convert to a Rational.

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.

ParseError

Unspecified problem while parsing an expression

SqrtNegative

Tried to take the Square Root of a Negative, these values are Imaginary

DivideByZero

Tried to divide by Zero, also arises if attempting to make a fraction with a zero denominator

NotFound

The specified identifier in an expression was not found

InsufficientParameters

The expression has too few parameters to evaluate

NotANumber

Tried to convert a floating point NaN, which has no equivalent or evaluated the Logarithm of a non-positive value or evaluated some other function outside its domain

Infinity

Tried to convert a floating point Infinity which has no equivalent

BadFraction

When parsing a fraction either the numerator or denominator weren’t decimal digits

BadDecimal

When parsing a decimal there was non-digits on one or both sides of the decimal point

BadInteger

When parsing an integer there were non-digits in the text

OutOfRange

The integer was outside the range for the chosen type

NotAnInteger

The rational was not an integer

Exhausted

Operation was rejected because it was likely to consume all available resources

UnknownZero

A checked operation could not prove that a value was non-zero.

This is distinct from Problem::DivideByZero: exact-real algorithms sometimes have enough structural information to reject definite zero, but not enough to certify non-zero without unbounded refinement.

Trait Implementations

impl Clone for Problem

fn clone(&self) -> Problem

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Problem

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

Formats the value using the given formatter.

impl Display for Problem

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

Formats the value using the given formatter.

impl Error for Problem

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 PartialEq for Problem

fn eq(&self, other: &Problem) -> 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 Copy for Problem

impl StructuralPartialEq for Problem