Struct Filter 

pub struct Filter { /* private fields */ }

A parsed filter expression.

The mini-DSL supports a conjunction of comparisons joined by and:

filter := clause ( " and " clause )*
clause := field op literal
op     := "==" | "!=" | "<=" | ">=" | "<" | ">"
literal := number | 'string' | "string" | true | false | null | bareword

Examples

use sheeter_engine::Filter;
use sheeter_engine::CanonicalValue;

let f = Filter::parse("age > 30 and name == 'Bob'").unwrap();
let row = CanonicalValue::Object(vec![
    ("age".to_string(), CanonicalValue::Number(serde_json::Number::from(40))),
    ("name".to_string(), CanonicalValue::String("Bob".to_string())),
]);
assert!(f.matches(&row));

Implementations

impl Filter

pub fn parse(input: &str) -> Result<Self, Box<dyn Error>>

Parses a filter expression.

Errors

Returns an error if the expression has no valid clause.

pub fn matches(&self, row: &CanonicalValue) -> bool

Returns true if the row (a CanonicalValue::Object) satisfies the filter.

Trait Implementations

impl Clone for Filter

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Filter

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

Formats the value using the given formatter.