Struct Case 

pub struct Case {
    pub expr: Option<Box<Expr>>,
    pub when_then_expr: Vec<(Box<Expr>, Box<Expr>)>,
    pub else_expr: Option<Box<Expr>>,
}

CASE expression

The CASE expression is similar to a series of nested if/else and there are two forms that can be used. The first form consists of a series of boolean “when” expressions with corresponding “then” expressions, and an optional “else” expression.

CASE WHEN condition THEN result
     [WHEN ...]
     [ELSE result]
END

The second form uses a base expression and then a series of “when” clauses that match on a literal value.

CASE expression
    WHEN value THEN result
    [WHEN ...]
    [ELSE result]
END

Fields

expr: Option<Box<Expr>>

Optional base expression that can be compared to literal values in the “when” expressions

when_then_expr: Vec<(Box<Expr>, Box<Expr>)>

One or more when/then expressions

else_expr: Option<Box<Expr>>

Optional “else” expression

Implementations

impl Case

pub fn new( expr: Option<Box<Expr>>, when_then_expr: Vec<(Box<Expr>, Box<Expr>)>, else_expr: Option<Box<Expr>>, ) -> Self

Create a new Case expression

Trait Implementations

impl Clone for Case

fn clone(&self) -> Case

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Case

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

Formats the value using the given formatter.

impl Hash for Case

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 Case

fn eq(&self, other: &Case) -> 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 Case

fn partial_cmp(&self, other: &Case) -> 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 Eq for Case

impl StructuralPartialEq for Case