Enum Element 

pub enum Element {
    Variable(Variable),
    Aggregate(Aggregate),
    Corresponding(Variable),
    Pull(Pull),
}

Variants

Variable(Variable)

Aggregate(Aggregate)

Corresponding(Variable)

In a query with a max or min aggregate, a corresponding variable (indicated in the query with (the ?var), is guaranteed to come from the row that provided the max or min value. Queries with more than one max or min cannot yield predictable behavior, and will err during algebrizing.

Pull(Pull)

Implementations

impl Element

pub fn is_unit(&self) -> bool

Returns true if the element must yield only one value.

Trait Implementations

impl Clone for Element

fn clone(&self) -> Element

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Element

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

Formats the value using the given formatter.

impl Display for Element

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

Formats the value using the given formatter.

impl Eq for Element

impl From<Variable> for Element

fn from(x: Variable) -> Element

Converts to this type from the input type.

impl PartialEq for Element

fn eq(&self, other: &Element) -> 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 StructuralPartialEq for Element