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Merge pull request #39 from dantleech/filter-dsl
Filter dsl
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,128 @@ | ||
| use std::collections::HashMap; | ||
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| use super::parser::{Expr, Parser}; | ||
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| pub type Vars = HashMap<String, Evalue>; | ||
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| pub struct Evaluator {} | ||
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| #[derive(PartialEq, PartialOrd, Debug, Clone)] | ||
| pub enum Evalue { | ||
| String(String), | ||
| Number(f64), | ||
| Bool(bool), | ||
| } | ||
| impl Evalue { | ||
| fn to_bool(&self) -> bool { | ||
| match self { | ||
| Evalue::String(v) => v != "" && v != "0", | ||
| Evalue::Number(n) => *n != 0.0, | ||
| Evalue::Bool(b) => *b, | ||
| } | ||
| } | ||
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| fn to_string(&self) -> String { | ||
| match self { | ||
| Evalue::String(v) => v.clone(), | ||
| Evalue::Number(n) => format!("{}", *n), | ||
| Evalue::Bool(b) => match b { | ||
| true => "true".to_string(), | ||
| false => "false".to_string(), | ||
| }, | ||
| } | ||
| } | ||
| } | ||
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| impl Evaluator { | ||
| pub fn new() -> Evaluator { | ||
| Evaluator {} | ||
| } | ||
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| pub fn parse(&mut self, expr: &str) -> Result<Expr, String> { | ||
| Parser::new(expr).parse() | ||
| } | ||
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| pub fn parse_and_evaluate(&mut self, expr: &str, vars: &Vars) -> Result<bool, String> { | ||
| let expr = Parser::new(expr).parse()?; | ||
| self.evaluate(&expr, vars) | ||
| } | ||
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| pub fn evaluate(&self, expr: &Expr, vars: &Vars) -> Result<bool, String> { | ||
| match self.evaluate_expr(&expr, vars)? { | ||
| Evalue::String(_) | Evalue::Number(_) => { | ||
| Err(format!("expression must evluate to a boolean, got: {:?}", expr).to_string()) | ||
| } | ||
| Evalue::Bool(b) => Ok(b), | ||
| } | ||
| } | ||
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| fn evaluate_expr(&self, expr: &super::parser::Expr, vars: &Vars) -> Result<Evalue, String> { | ||
| match expr { | ||
| super::parser::Expr::Boolean(b) => Ok(Evalue::Bool(*b)), | ||
| super::parser::Expr::String(s) => Ok(Evalue::String(s.clone())), | ||
| super::parser::Expr::Binary(lexpr, op, rexpr) => { | ||
| let lval = self.evaluate_expr(lexpr, vars)?; | ||
| let rval = self.evaluate_expr(rexpr, vars)?; | ||
| let eval = match op { | ||
| super::lexer::TokenKind::GreaterThan => Ok(lval > rval), | ||
| super::lexer::TokenKind::GreaterThanEqual => Ok(lval >= rval), | ||
| super::lexer::TokenKind::LessThanEqual => Ok(lval <= rval), | ||
| super::lexer::TokenKind::LessThan => Ok(lval < rval), | ||
| super::lexer::TokenKind::Equal => Ok(lval == rval), | ||
| super::lexer::TokenKind::FuzzyEqual => Ok(lval.to_string().contains(rval.to_string().as_str())), | ||
| super::lexer::TokenKind::NotEqual => Ok(lval != rval), | ||
| super::lexer::TokenKind::NotFuzzyEqual => Ok(!lval.to_string().contains(rval.to_string().as_str())), | ||
| super::lexer::TokenKind::Or => Ok(lval.to_bool() || rval.to_bool()), | ||
| super::lexer::TokenKind::And => Ok(lval.to_bool() && rval.to_bool()), | ||
| _ => Err(format!("unknown operator: {:?}", op)), | ||
| }?; | ||
| Ok(Evalue::Bool(eval)) | ||
| } | ||
| super::parser::Expr::Number(n) => Ok(Evalue::Number(*n)), | ||
| super::parser::Expr::Variable(v) => match vars.get(v) { | ||
| Some(v) => Ok(v.clone()), | ||
| None => Err(format!("Unknown variable `{}`", v)), | ||
| }, | ||
| } | ||
| } | ||
| } | ||
|
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| #[cfg(test)] | ||
| mod test { | ||
| use super::*; | ||
|
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| #[test] | ||
| fn test_evaluate() { | ||
| let result = Evaluator::new().parse_and_evaluate("false", &HashMap::new()); | ||
| assert_eq!(false, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("20 > 10", &HashMap::new()); | ||
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| assert_eq!(true, result.unwrap()); | ||
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| let result = Evaluator::new().parse_and_evaluate("20 > 10 and false", &HashMap::new()); | ||
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| assert_eq!(false, result.unwrap()); | ||
| } | ||
|
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| #[test] | ||
| fn test_evaluate_params() { | ||
| let map = HashMap::from([ | ||
| ("distance".to_string(), Evalue::Number(10.0)), | ||
| ("type".to_string(), Evalue::String("Run".to_string())), | ||
| ]); | ||
| let result = Evaluator::new().parse_and_evaluate("distance > 5", &map); | ||
| assert_eq!(true, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("distance < 5", &map); | ||
| assert_eq!(false, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("distance = 10", &map); | ||
| assert_eq!(true, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("type = 'Run'", &map); | ||
| assert_eq!(true, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("type ~ 'Ru'", &map); | ||
| assert_eq!(true, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("type !~ 'Rup'", &map); | ||
| assert_eq!(true, result.unwrap()); | ||
| let result = Evaluator::new().parse_and_evaluate("type != 'Run'", &map); | ||
| assert_eq!(false, result.unwrap()); | ||
| } | ||
| } |
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