fix #2

src/lib.rs

@@ -594,6 +594,13 @@ mod tests {
 
         assert_eq!(tree.parse_node(), Err(Error::CommaNotWithFunction));
     }
+
+    #[test]
+    fn test_eval_issue_2() {
+        assert_eq!(eval("2 * (4 + 0) + 4"), Ok(to_value(12)));
+        assert_eq!(eval("2 * (2 + 2) + (1 + 3)"), Ok(to_value(12)));
+        assert_eq!(eval("2 * (4) + (4)"), Ok(to_value(12)));
+    }
 }
 
 #[cfg(all(feature = "unstable", test))]

src/node/mod.rs

@@ -14,7 +14,7 @@ pub struct Node {
 impl Node {
     pub fn new(operator: Operator) -> Node {
         Node {
-            operator: operator,
+            operator,
             children: Vec::new(),
             closed: false,
         }
@@ -47,7 +47,7 @@ impl Node {
         }
     }
 
-    pub fn is_value_or_enough(&self) -> bool {
+    pub fn is_value_or_full_children(&self) -> bool {
         if self.operator.is_value_or_ident() {
             true
         } else if self.operator.can_have_child() {
@@ -57,6 +57,10 @@ impl Node {
         }
     }
 
+    pub fn is_unclosed_arithmetic(&self) -> bool {
+        return !self.closed && self.operator.can_have_child() && self.operator.can_have_child()
+    }
+
     pub fn is_unclosed_function(&self) -> bool {
         match self.operator {
             Operator::Function(_) => !self.closed,

src/tree/mod.rs

@@ -205,7 +205,7 @@ impl Tree {
                 Operator::Rem(priority) => {
                     if !parsing_nodes.is_empty() {
                         let prev = parsing_nodes.pop().unwrap();
-                        if prev.is_value_or_enough() {
+                        if prev.is_value_or_full_children() {
                             if prev.operator.get_priority() < priority && !prev.closed {
                                 parsing_nodes.extend_from_slice(&rob_to(prev, operator.to_node()));
                             } else {
@@ -468,7 +468,7 @@ fn append_value_to_last_node(parsing_nodes: &mut Vec<Node>,
         } else if prev.is_left_square_bracket() {
             parsing_nodes.push(prev);
             parsing_nodes.push(node);
-        } else if prev.is_value_or_enough() {
+        } else if prev.is_value_or_full_children() {
             return Err(Error::DuplicateValueNode);
         } else if prev.is_enough() {
             parsing_nodes.push(prev);
@@ -535,6 +535,9 @@ fn close_bracket(parsing_nodes: &mut Vec<Node>, bracket: Operator) -> Result<(),
                     penult.closed = true;
                     penult.add_child(current);
                     parsing_nodes.push(penult);
+                } else if penult.is_unclosed_arithmetic() {
+                    penult.add_child(current);
+                    parsing_nodes.push(penult);
                 } else {
                     parsing_nodes.push(penult);
                     parsing_nodes.push(current);