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 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 PartialEq for Expr

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