fixing parsing and eval pure constant, writing a test for it

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bool_expr_parser_nom"
-version = "0.2.3"
+version = "0.2.4"
 edition = "2021"
 authors = ["Nikolajus Krauklis <[email protected]>"]
 

src/eval.rs

@@ -5,6 +5,19 @@ use crate::ast::{AstNode, Atom, ComparisonOp};
 pub fn eval<'a>(expr: &AstNode, context: &HashMap<&str, Atom>) -> Result<bool, &'a str> {
     let mut result = false;
     result = match expr {
+        AstNode::Constant(var) => {
+            let mut result = false;
+            if let Atom::Boolean(v) = var {
+                result = *v;
+            }
+            if let Atom::Variable(v) = var {
+                let context_val = context.get(v.as_str());
+                if let Some(Atom::Boolean(inner)) = context_val {
+                    result = *inner;
+                }
+            }
+            result
+        }
         AstNode::Compare(var, op, val) => {
             // check var in context
             // compare with val
@@ -90,6 +103,18 @@ mod tests {
         );
     }
 
+    #[test]
+    fn simple_constant_eval_test() {
+        assert_eq!(
+            false,
+            eval(&parse("false").unwrap().1, &HashMap::from([])).unwrap()
+        );
+        assert_eq!(
+            true,
+            eval(&parse("TRUE").unwrap().1, &HashMap::from([])).unwrap()
+        );
+    }
+
     #[test]
     fn test_logic_expr_eval() {
 

src/parse.rs

@@ -209,6 +209,7 @@ fn parse_expr(input: &str) -> IResult<&str, AstNode> {
         parse_parenthesized_expr,
         parse_logic_expr,
         parse_compare_or_array_expr,
+        parse_constant,
     ))(input)
     .expect("parse failed");
 
@@ -232,6 +233,13 @@ pub fn parse(i: &str) -> IResult<&str, AstNode> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn parse_constant_test() {
+        let res = parse("True");
+        assert_eq!(true, res.is_ok());
+        assert_eq!(AstNode::Constant(Atom::Boolean(true)), res.unwrap().1);
+    }
+
     #[test]
     fn test_parse_bool() {
         let (_, v) = parse_boolean("True").unwrap();