Function parse_str 

pub fn parse_str(query: impl AsRef<str>) -> Result<Expr, ParseError>

Parses an OData v4 $filter expression string into an Expr AST.

A result containing the parsed Expr on success, or an Error on failure.

use odata_params::filters::parse_str;

let filter = "name eq 'John' and isActive eq true";
let result = parse_str(filter).expect("valid filter tree");