Enum CastSyntax 

pub enum CastSyntax {
    Call,
    DoubleColon,
    PrefixTyped,
    Convert,
}

How a cast is spelled.

One canonical Expr::Cast shape covers all three spellings; this tag records which surface form the source used so rendering round-trips: the standard CAST(expr AS type) call, the PostgreSQL expr::type postfix operator, or the PostgreSQL prefixed typed string constant type 'string'.

Variants

Call

CAST(expr AS type).

DoubleColon

expr::type (PostgreSQL).

PrefixTyped

type 'string' — a typed string constant whose semantics are a cast of the string to the named type (PostgreSQL’s generalized ConstTypename Sconst / func_name Sconst, e.g. float8 'NaN', int4 '42', double precision '1.5'). The operand is always a string constant; the canonical shape is the same Expr::Cast as 'NaN'::float8 and CAST('NaN' AS float8), so only this tag and the rendered spelling distinguish the three.

Convert

CONVERT(<expr>, <type>) — MySQL’s comma-form cast, the same canonical Expr::Cast shape as CAST(<expr> AS <type>) with only this tag (and the rendered spelling) distinguishing it. The target is the identical restricted cast_type set as CAST under CallSyntax::restricted_cast_targets — engine-measured on mysql:8.4, CONVERT(1, INT) / CONVERT(x, VARCHAR) reject exactly as the matching CAST forms do, and the charset-annotated CHAR target rides in free via the shared type grammar. Recognized only under CallSyntax::convert_function; MySQL-only. The transcoding CONVERT(<expr> USING <charset>) form is a different production — StringFunc::ConvertUsing, not a cast.

Trait Implementations

impl Clone for CastSyntax

fn clone(&self) -> CastSyntax

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CastSyntax

impl Debug for CastSyntax

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CastSyntax

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for CastSyntax

impl Hash for CastSyntax

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for CastSyntax

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for CastSyntax

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for CastSyntax