Added negate operator '!' (#54)

* Added negate operator '!'

* Fix chaining '!' by moving the logic_not before parsing logic_atom

* rustfmt fail fix

README.md

@@ -86,6 +86,7 @@ following elements:
 
 | Expression sign | Description                                                                                | Where to use                                                                                             |
 |-----------------|--------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------|
+| `!`             | Not                                                                                        | To negate the expression                                                                                 |
 | `==`            | Equal                                                                                      | To compare numbers or string literals                                                                    |
 | `!=`            | Unequal                                                                                    | To compare numbers or string literals in opposite way to equals                                          |
 | `<`             | Less                                                                                       | To compare numbers                                                                                       |
@@ -99,7 +100,7 @@ following elements:
 | `noneOf`        | The left size has no intersection with right                                               |                                                                                                          |
 | `anyOf`         | The left size has at least one intersection with right                                     |                                                                                                          |
 | `subsetOf`      | The left is a subset of the right side                                                     |                                                                                                          |
-|                 | Exists operator.                                                                           | The operator checks the existence of the field depicted on the left side like that `[?(@.key.isActive)]` |
+| `?`             | Exists operator.                                                                           | The operator checks the existence of the field depicted on the left side like that `[?(@.key.isActive)]` |
 
 Filter expressions can be chained using `||` and `&&` (logical or and logical and correspondingly) in the following way:
 

src/lib.rs

@@ -1244,6 +1244,66 @@ mod tests {
         );
     }
 
+    #[test]
+    fn logical_not_exp_test() {
+        let json: Box<Value> = Box::new(json!({"first":{"second":{"active":1}}}));
+        let path: Box<JsonPathInst> = Box::from(
+            JsonPathInst::from_str("$.first[?(!@.does_not_exist >= 1.0)]")
+                .expect("the path is correct"),
+        );
+        let finder = JsonPathFinder::new(json.clone(), path);
+        let v = finder.find_slice();
+        assert_eq!(
+            v,
+            vec![Slice(
+                &json!({"second":{"active": 1}}),
+                "$.['first']".to_string()
+            )]
+        );
+
+        let path: Box<JsonPathInst> = Box::from(
+            JsonPathInst::from_str("$.first[?(!(@.does_not_exist >= 1.0))]")
+                .expect("the path is correct"),
+        );
+        let finder = JsonPathFinder::new(json.clone(), path);
+        let v = finder.find_slice();
+        assert_eq!(
+            v,
+            vec![Slice(
+                &json!({"second":{"active": 1}}),
+                "$.['first']".to_string()
+            )]
+        );
+
+        let path: Box<JsonPathInst> = Box::from(
+            JsonPathInst::from_str("$.first[?(!(@.second.active == 1) || @.second.active == 1)]")
+                .expect("the path is correct"),
+        );
+        let finder = JsonPathFinder::new(json.clone(), path);
+        let v = finder.find_slice();
+        assert_eq!(
+            v,
+            vec![Slice(
+                &json!({"second":{"active": 1}}),
+                "$.['first']".to_string()
+            )]
+        );
+
+        let path: Box<JsonPathInst> = Box::from(
+            JsonPathInst::from_str("$.first[?(!@.second.active == 1 && !@.second.active == 1 || !@.second.active == 2)]")
+                .expect("the path is correct"),
+        );
+        let finder = JsonPathFinder::new(json, path);
+        let v = finder.find_slice();
+        assert_eq!(
+            v,
+            vec![Slice(
+                &json!({"second":{"active": 1}}),
+                "$.['first']".to_string()
+            )]
+        );
+    }
+
     // #[test]
     // fn no_value_len_field_test() {
     //     let json: Box<Value> =

src/parser/grammar/json_path.pest

@@ -19,6 +19,7 @@ char = _{
 }
 root = {"$"}
 sign = { "==" | "!=" | "~=" | ">=" | ">" | "<=" | "<" | "in" | "nin" | "size" | "noneOf" | "anyOf" | "subsetOf"}
+not = {"!"}
 key_lim = {!"length()" ~ (word | ASCII_DIGIT | specs)+}
 key_unlim = {"[" ~ string_qt ~ "]"}
 key = ${key_lim | key_unlim}
@@ -38,11 +39,12 @@ slice = {start_slice? ~ col ~ end_slice? ~ step_slice? }
 
 unit_keys = { string_qt ~ ("," ~ string_qt)+ }
 unit_indexes = { number ~ ("," ~ number)+  }
-filter = {"?"~ "(" ~ logic ~ ")"}
+filter = {"?"~ "(" ~ logic_or ~ ")"}
 
-logic = {logic_and ~ ("||" ~ logic_and)*}
-logic_and = {logic_atom ~ ("&&" ~ logic_atom)*}
-logic_atom = {atom ~ (sign ~ atom)? | "(" ~ logic ~ ")"}
+logic_or = {logic_and ~ ("||" ~ logic_and)*}
+logic_and = {logic_not ~ ("&&" ~ logic_not)*}
+logic_not = {not? ~ logic_atom}
+logic_atom = {atom ~ (sign ~ atom)? | "(" ~ logic_or ~ ")"}
 
 atom = {chain | string_qt | number | boolean | null}
 

src/parser/model.rs

@@ -69,6 +69,8 @@ pub enum FilterExpression {
     And(Box<FilterExpression>, Box<FilterExpression>),
     /// or with ||
     Or(Box<FilterExpression>, Box<FilterExpression>),
+    /// not with !
+    Not(Box<FilterExpression>),
 }
 
 impl FilterExpression {

src/parser/parser.rs

@@ -1,6 +1,6 @@
 use crate::parser::errors::JsonPathParserError::ParserError;
 use crate::parser::errors::{parser_err, JsonPathParserError};
-use crate::parser::model::FilterExpression::{And, Or};
+use crate::parser::model::FilterExpression::{And, Not, Or};
 use crate::parser::model::{
     FilterExpression, FilterSign, Function, JsonPath, JsonPathIndex, Operand,
 };
@@ -145,10 +145,10 @@ fn parse_chain_in_operand(rule: Pair<Rule>) -> Result<Operand, JsonPathParserErr
 }
 
 fn parse_filter_index(pair: Pair<Rule>) -> Result<JsonPathIndex, JsonPathParserError> {
-    Ok(JsonPathIndex::Filter(parse_logic(pair.into_inner())?))
+    Ok(JsonPathIndex::Filter(parse_logic_or(pair.into_inner())?))
 }
 
-fn parse_logic(pairs: Pairs<Rule>) -> Result<FilterExpression, JsonPathParserError> {
+fn parse_logic_or(pairs: Pairs<Rule>) -> Result<FilterExpression, JsonPathParserError> {
     let mut expr: Option<FilterExpression> = None;
     let error_message = format!("Failed to parse logical expression: {:?}", pairs);
     for pair in pairs {
@@ -168,7 +168,7 @@ fn parse_logic_and(pairs: Pairs<Rule>) -> Result<FilterExpression, JsonPathParse
     let mut expr: Option<FilterExpression> = None;
     let error_message = format!("Failed to parse logical `and` expression: {:?}", pairs,);
     for pair in pairs {
-        let next_expr = parse_logic_atom(pair.into_inner())?;
+        let next_expr = parse_logic_not(pair.into_inner())?;
         match expr {
             None => expr = Some(next_expr),
             Some(e) => expr = Some(And(Box::new(e), Box::new(next_expr))),
@@ -180,10 +180,26 @@ fn parse_logic_and(pairs: Pairs<Rule>) -> Result<FilterExpression, JsonPathParse
     }
 }
 
+fn parse_logic_not(mut pairs: Pairs<Rule>) -> Result<FilterExpression, JsonPathParserError> {
+    if let Some(rule) = pairs.peek().map(|x| x.as_rule()) {
+        match rule {
+            Rule::not => {
+                pairs.next().expect("unreachable in arithmetic: should have a value as pairs.peek() was Some(_)");
+                parse_logic_not(pairs)
+                    .map(|expr|Not(Box::new(expr)))
+            },
+            Rule::logic_atom => parse_logic_atom(pairs.next().expect("unreachable in arithmetic: should have a value as pairs.peek() was Some(_)").into_inner()),
+            x => Err(JsonPathParserError::UnexpectedRuleLogicError(x, pairs)),
+        }
+    } else {
+        Err(JsonPathParserError::UnexpectedNoneLogicError(pairs))
+    }
+}
+
 fn parse_logic_atom(mut pairs: Pairs<Rule>) -> Result<FilterExpression, JsonPathParserError> {
     if let Some(rule) = pairs.peek().map(|x| x.as_rule()) {
         match rule {
-            Rule::logic => parse_logic(pairs.next().expect("unreachable in arithmetic: should have a value as pairs.peek() was Some(_)").into_inner()),
+            Rule::logic_or => parse_logic_or(pairs.next().expect("unreachable in arithmetic: should have a value as pairs.peek() was Some(_)").into_inner()),
             Rule::atom => {
                 let left: Operand = parse_atom(pairs.next().unwrap())?;
                 if pairs.peek().is_none() {

src/path/index.rs

@@ -205,6 +205,9 @@ pub enum FilterPath<'a> {
         left: PathInstance<'a>,
         right: PathInstance<'a>,
     },
+    Not {
+        exp: PathInstance<'a>,
+    },
 }
 
 impl<'a> FilterPath<'a> {
@@ -223,6 +226,9 @@ impl<'a> FilterPath<'a> {
                 left: Box::new(FilterPath::new(l, root)),
                 right: Box::new(FilterPath::new(r, root)),
             },
+            FilterExpression::Not(exp) => FilterPath::Not {
+                exp: Box::new(FilterPath::new(exp, root)),
+            },
         }
     }
     fn compound(
@@ -307,6 +313,9 @@ impl<'a> FilterPath<'a> {
                     !JsonPathValue::vec_as_data(right.find(Slice(curr_el, pref))).is_empty()
                 }
             }
+            FilterPath::Not { exp } => {
+                JsonPathValue::vec_as_data(exp.find(Slice(curr_el, pref))).is_empty()
+            }
         }
     }
 }