Enum mz_sql::plan::typeconv::CastContext

pub enum CastContext {
    Implicit,
    Assignment,
    Explicit,
    Coerced,
}

Describes the context of a cast.

n.b. this type derived Ord, PartialOrd and the ordering of these values has semantics meaning; casts are only permitted when the caller’s cast context is geq the ccx we store, which is the minimum required context.

Variants

Implicit

Implicit casts are “no-brainer” casts that apply automatically in expressions. They are typically lossless, such as ScalarType::Int32 to ScalarType::Int64.

Assignment

Assignment casts are “reasonable” casts that make sense to apply automatically in INSERT statements, but are surprising enough that they don’t apply implicitly in expressions.

Explicit

Explicit casts are casts that are possible but may be surprising, like casting ScalarType::Json to ScalarType::Int32, and therefore they do not happen unless explicitly requested by the user with a cast operator.

Coerced

Coerced casts permit different behavior when a type is coerced from a string literal vs. a value of type pg_catalog::text.

The only call site that should pass this value in to this module is string coercion.

Trait Implementations

impl Clone for CastContext

fn clone(&self) -> CastContext

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CastContext

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

Formats the value using the given formatter.

impl Ord for CastContext

fn cmp(&self, other: &CastContext) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for CastContext

fn eq(&self, other: &CastContext) -> 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 PartialOrd for CastContext

fn partial_cmp(&self, other: &CastContext) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for CastContext

impl Eq for CastContext

impl StructuralPartialEq for CastContext