Enum Expr 

pub enum Expr {
    Field(String),
    Str(String),
    I64(i64),
    F64(f64),
    Bool(bool),
    Null,
    Array(Vec<Expr>),
    FuncCall(String, Vec<Expr>),
    MethodCall(String, Box<Expr>, Vec<Expr>),
    Gt(Box<Expr>, Box<Expr>),
    Lt(Box<Expr>, Box<Expr>),
    Ge(Box<Expr>, Box<Expr>),
    Le(Box<Expr>, Box<Expr>),
    Eq(Box<Expr>, Box<Expr>),
    Ne(Box<Expr>, Box<Expr>),
    In(Box<Expr>, Box<Expr>),
    And(Vec<Expr>),
    Or(Vec<Expr>),
    Not(Box<Expr>),
}

The expression.

It is an AST of the filter expression.

Variants

Field(String)

Str(String)

I64(i64)

F64(f64)

Bool(bool)

Null

Array(Vec<Expr>)

FuncCall(String, Vec<Expr>)

MethodCall(String, Box<Expr>, Vec<Expr>)

Gt(Box<Expr>, Box<Expr>)

Lt(Box<Expr>, Box<Expr>)

Ge(Box<Expr>, Box<Expr>)

Le(Box<Expr>, Box<Expr>)

Eq(Box<Expr>, Box<Expr>)

Ne(Box<Expr>, Box<Expr>)

In(Box<Expr>, Box<Expr>)

And(Vec<Expr>)

Or(Vec<Expr>)

Not(Box<Expr>)

Implementations

impl Expr

pub fn field_<T: Into<String>>(field: T) -> Self

pub fn str_<T: Into<String>>(value: T) -> Self

pub fn i64_<T: Into<i64>>(value: T) -> Self

pub fn f64_<T: Into<f64>>(value: T) -> Self

pub fn bool_<T: Into<bool>>(value: T) -> Self

pub fn null_() -> Self

pub fn array_<T: Into<Vec<Expr>>>(value: T) -> Self

pub fn func_call_(func: impl Into<String>, args: Vec<Expr>) -> Self

pub fn method_call_( obj: Expr, method: impl Into<String>, args: Vec<Expr>, ) -> Self

pub fn gt_(left: Expr, right: Expr) -> Self

pub fn lt_(left: Expr, right: Expr) -> Self

pub fn ge_(left: Expr, right: Expr) -> Self

pub fn le_(left: Expr, right: Expr) -> Self

pub fn eq_(left: Expr, right: Expr) -> Self

pub fn ne_(left: Expr, right: Expr) -> Self

pub fn in_(left: Expr, right: Expr) -> Self

pub fn and_<T: Into<Vec<Expr>>>(value: T) -> Self

pub fn or_<T: Into<Vec<Expr>>>(value: T) -> Self

pub fn not_(self) -> Self

impl Expr

pub async fn transform<F: Transform>( self, transformer: &mut F, ) -> Result<Expr, Error>

Recursively transform an expression using the provided transformer.

use filter_expr::{Expr, Transform};
use async_trait::async_trait;

struct MyTransformer;

#[async_trait]
impl Transform for MyTransformer {
    async fn transform(&mut self, expr: Expr) -> Result<Expr, filter_expr::Error> {
        // Transform the expression before recursing
        Ok(match expr {
            Expr::Field(name) if name == "old_name" => {
                Expr::Field("new_name".to_string())
            }
            other => other,
        })
    }
}

let expr = Expr::Field("old_name".to_string());
let mut transformer = MyTransformer;
let result = expr.transform(&mut transformer).await.unwrap();
assert_eq!(result, Expr::Field("new_name".to_string()));

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.

impl Hash for Expr

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 Expr

fn cmp(&self, other: &Self) -> 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 Expr

fn eq(&self, other: &Self) -> 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 Expr

fn partial_cmp(&self, other: &Self) -> 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 Expr