Enum ExpressionKind

pub enum ExpressionKind {
    Lit(Literal),
    Ident(Ident),
    StreamAccess(Box<Expression>, StreamAccessKind),
    Default(Box<Expression>, Box<Expression>),
    Offset(Box<Expression>, Offset),
    DiscreteWindowAggregation {
        expr: Box<Expression>,
        duration: Box<Expression>,
        wait: bool,
        aggregation: WindowOperation,
    },
    SlidingWindowAggregation {
        expr: Box<Expression>,
        duration: Box<Expression>,
        wait: bool,
        aggregation: WindowOperation,
    },
    InstanceAggregation {
        expr: Box<Expression>,
        selection: InstanceSelection,
        aggregation: InstanceOperation,
    },
    Binary(BinOp, Box<Expression>, Box<Expression>),
    Unary(UnOp, Box<Expression>),
    Ite(Box<Expression>, Box<Expression>, Box<Expression>),
    ParenthesizedExpression(Box<Expression>),
    MissingExpression,
    Tuple(Vec<Expression>),
    Field(Box<Expression>, Ident),
    Method(Box<Expression>, FunctionName, Vec<Type>, Vec<Expression>),
    Function(FunctionName, Vec<Type>, Vec<Expression>),
    Lambda(LambdaExpr),
}

The Ast representation of a single expression

Variants

Lit(Literal)

A literal, e.g., 1, "foo"

Ident(Ident)

An identifier, e.g., foo

StreamAccess(Box<Expression>, StreamAccessKind)

Accessing a stream

Default(Box<Expression>, Box<Expression>)

A default expression, e.g., a.defaults(to: 0)

Offset(Box<Expression>, Offset)

An offset expression, e.g., a.offset(by: -1)

DiscreteWindowAggregation

A discrete window with a duration duration as an integer constant and aggregation function aggregation

Fields

expr: Box<Expression>

The accesses stream

duration: Box<Expression>

The duration of the window

wait: bool

Flag to mark that the window returns only a value if the complete duration has passed

aggregation: WindowOperation

The aggregation function

SlidingWindowAggregation

A sliding window with duration duration and aggregation function aggregation

Fields

expr: Box<Expression>

The accesses stream

duration: Box<Expression>

The duration of the window

wait: bool

Flag to mark that the window returns only a value if the complete duration has passed

aggregation: WindowOperation

The aggregation function

InstanceAggregation

A aggregation over stream-instances with instances instances and aggregation function aggregation

Fields

expr: Box<Expression>

The accesses stream

selection: InstanceSelection

Flag to indicate which instances are part of the aggregation

aggregation: InstanceOperation

The aggregation function

Binary(BinOp, Box<Expression>, Box<Expression>)

A binary operation (For example: a + b, a * b)

Unary(UnOp, Box<Expression>)

A unary operation (For example: !x, *x)

Ite(Box<Expression>, Box<Expression>, Box<Expression>)

An if-then-else expression

ParenthesizedExpression(Box<Expression>)

An expression enveloped in parentheses

MissingExpression

An expression was expected, e.g., after an operator like *

Tuple(Vec<Expression>)

A tuple expression

Field(Box<Expression>, Ident)

Access of a named (obj.foo) or unnamed (obj.0) struct field

Method(Box<Expression>, FunctionName, Vec<Type>, Vec<Expression>)

A method call, e.g., foo.bar(-1)

Function(FunctionName, Vec<Type>, Vec<Expression>)

A function call

Lambda(LambdaExpr)

A lambda expression used in filtered instance aggregations

Trait Implementations

impl Clone for ExpressionKind

fn clone(&self) -> ExpressionKind

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExpressionKind

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

Formats the value using the given formatter.

impl Hash for ExpressionKind

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 Ord for ExpressionKind

fn cmp(&self, other: &ExpressionKind) -> 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,

Restrict a value to a certain interval.

impl PartialEq for ExpressionKind

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

fn partial_cmp(&self, other: &ExpressionKind) -> 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 ExpressionKind

impl StructuralPartialEq for ExpressionKind