diff --git a/src/parser/deimos.pest b/src/parser/deimos.pest
index 3fc0dc5..137a88a 100644
--- a/src/parser/deimos.pest
+++ b/src/parser/deimos.pest
@@ -67,13 +67,46 @@ Statement = { VariableDeclaration | CallExpression | AssignmentExpression }
 VariableDeclaration = { "let" ~ Mutable? ~ Identifier ~ TypeAnnotation? ~ ( "=" ~ Expression )? }
 
 // Expressions
-Expression = { CallExpression | AssignmentExpression | Literal | ObjectAccess }
-ExpressionList = { Expression ~ ( "," ~ Expression )* }
+Expression = { OrExpression }
 
-// Calls
-CallExpression = { ObjectAccess ~ GenericArguments? ~ CallArguments }
+OrExpression = { AndExpression ~ ( "||" ~ AndExpression )* }
+AndExpression = { EqualityExpression ~ ( "&&" ~ EqualityExpression )* }
+
+EqualityExpression = { ComparisonExpression ~ ( ( EqualTo | NotEqualTo ) ~ ComparisonExpression )* }
+EqualTo = { "==" }
+NotEqualTo = { "!=" }
+
+ComparisonExpression = { AdditiveExpression ~ ( ( Greater | Less | GreaterEqual | LessEqual ) ~ AdditiveExpression )* }
+Greater = { ">" }
+Less = { "<" }
+GreaterEqual = { ">=" }
+LessEqual = { "<=" }
+
+AdditiveExpression = { MultiplicativeExpression ~ ( ( Add | Subtract ) ~ MultiplicativeExpression )* }
+Add = { "+" }
+Subtract = { "-" }
+
+MultiplicativeExpression = { UnaryExpression ~ ( ( Multiply | Divide | Modulo ) ~ UnaryExpression )* }
+Multiply = { "*" }
+Divide = { "/" }
+Modulo = { "%" }
+
+UnaryExpression = { ( Not | Negative )* ~ PrimaryExpression ~ ( Call | ( PlusPlus | MinusMinus ) )* }
+Not = { "!" }
+Negative = { "-" }
+PlusPlus = { "++" }
+MinusMinus = { "--" }
+
+PrimaryExpression = { Literal | ObjectAccess | ParenthesizedExpression }
+ParenthesizedExpression = { "(" ~ Expression ~ ")" }
+
+
+// Call
+CallExpression = { PrimaryExpression ~ Call+ }
+Call = { GenericArguments? ~ CallArguments }
+ExpressionList = { Expression ~ ( "," ~ Expression )* }
 CallArguments = {
-    ( "(" ~ ExpressionList? ~")")
+    ( "(" ~ ExpressionList? ~ ")" )
     | ExpressionList
 }
 
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 3f8af4b..d341bda 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -10,16 +10,30 @@ mod deimos_parser_tests {
     use pest::iterators::Pair;
     use pest::Parser;
 
+    macro_rules! fail_rule {
+        ($pair: expr; $rule:path) => {{
+            panic!(
+                "Expected {} but found {:?}",
+                stringify!($rule),
+                $pair.as_rule()
+            )
+        }};
+    }
+
+    macro_rules! match_rule {
+        ($pair:expr; $rule:path) => {{
+            if $rule != $pair.as_rule() {
+                fail_rule!($pair; $rule);
+            }
+        }};
+    }
+
     macro_rules! match_inner_rules {
         ($pair:expr; $rule:path; $handle_last:expr) => {{
             if let $rule = $pair.as_rule() {
                 $handle_last($pair);
             } else {
-                panic!(
-                    "Expected {} but found {:?}",
-                    stringify!($rule),
-                    $pair.as_rule()
-                )
+                fail_rule!($pair; $rule);
             }
         }};
         ($pair:expr; $head_rule:path $(, $tail_rules:path )* ; $handle_last:expr) => {{
@@ -31,11 +45,7 @@ mod deimos_parser_tests {
                     $handle_last
                 );
             } else {
-                panic!(
-                    "Expected {} but found {:?}",
-                    stringify!($head_rule),
-                    $pair.as_rule()
-                )
+                fail_rule!($pair; $head_rule);
             }
         }};
     }
@@ -61,4 +71,27 @@ mod deimos_parser_tests {
             assert_eq!(hexadecimal_base.as_str(), "0x123456789abcdef")
         })
     }
+
+    #[test]
+    fn identifier_call_as_expression() {
+        let pair = parse(Rule::Expression, "foo()");
+        match_inner_rules!(pair; Rule::Expression, Rule::OrExpression, Rule::AndExpression, Rule::EqualityExpression, Rule::ComparisonExpression, Rule::AdditiveExpression, Rule::MultiplicativeExpression, Rule::UnaryExpression; |unary_expression: Pair<Rule>| {
+            let mut unary_pairs = unary_expression.into_inner();
+            let primary_expression = unary_pairs.next().unwrap();
+            match_rule!(primary_expression; Rule::PrimaryExpression);
+            let call = unary_pairs.next().unwrap();
+            match_rule!(call; Rule::Call);
+        });
+    }
+    
+    #[test]
+    fn identifier_call_as_call_expression() {
+        let pair = parse(Rule::CallExpression, "foo()");
+        match_rule!(pair; Rule::CallExpression);
+        let mut call_expression_pairs = pair.into_inner();
+        let primary_expression = call_expression_pairs.next().unwrap();
+        match_rule!(primary_expression; Rule::PrimaryExpression);
+        let call = call_expression_pairs.next().unwrap();
+        match_rule!(call; Rule::Call);
+    }
 }