priority expression

src/parser/mod.rs

@@ -164,12 +164,13 @@ impl Parser {
             TokenType::Symbol(Symbol::LBrace) => Expression::BlockExpression(self.block()?),
 
             // match literal expressions with a semi-colon afterwards
-            TokenType::Number(_) | TokenType::String(_)
+            TokenType::Number(_) | TokenType::String(_) if !self_matches_peek!(self, TokenType::Symbol(s) if s.is_operator() || s.is_comparison() || s.is_logical()) => {
-                if !self_matches_peek!(self, TokenType::Symbol(s) if s.is_operator() || s.is_comparison() || s.is_logical()) =>
-            {
                 Expression::Literal(self.literal()?)
             }
 
+            // match priority expressions with a left parenthesis
+            TokenType::Symbol(Symbol::LParen) => Expression::PriorityExpression(self.priority()?), 
+
             _ => {
                 return Err(ParseError::UnexpectedToken {
                     token: current_token.clone(),
@@ -180,8 +181,25 @@ impl Parser {
         Ok(to_return)
     }
 
-    fn binary(&mut self) -> Result<BinaryExpression, ParseError> {
+    fn priority(&mut self) -> Result<Box<Expression>, ParseError> {
-        todo!()
+        let current_token = token_from_option!(self.current_token);
+        if !token_matches!(current_token, TokenType::Symbol(Symbol::LParen)) {
+            return Err(ParseError::UnexpectedToken {
+                token: current_token.clone(),
+            });
+        }
+
+        let expression = self.parse()?.ok_or(ParseError::UnexpectedEOF)?;
+
+        // make sure the next token is a right parenthesis
+        let current_token = token_from_option!(self.get_next()?);
+        if !token_matches!(current_token, TokenType::Symbol(Symbol::RParen)) {
+            return Err(ParseError::UnexpectedToken {
+                token: current_token.clone(),
+            });
+        }
+
+        Ok(Box::new(expression))
     }
 
     fn invocation(&mut self) -> Result<InvocationExpression, ParseError> {
@@ -470,6 +488,23 @@ mod tests {
 
         assert_eq!("add()", expression.to_string());
 
+        Ok(())
+    }
+
+    #[test]
+    fn test_priority_expression() -> Result<()> {
+        let input = r#"
+            let x = (4);
+        "#;
+
+        let tokenizer = Tokenizer::from(input.to_owned());
+        let mut parser = Parser::new(tokenizer);
+
+        let expression = parser.parse()?.unwrap();
+
+        assert_eq!("(let x = (4))", expression.to_string());
+
+
         Ok(())
     }
 }

src/parser/tree_node.rs

@@ -150,6 +150,7 @@ pub enum Expression {
     FunctionExpression(FunctionExpression),
     BlockExpression(BlockExpression),
     InvocationExpression(InvocationExpression),
+    PriorityExpression(Box<Expression>),
 }
 
 impl std::fmt::Display for Expression {
@@ -165,6 +166,7 @@ impl std::fmt::Display for Expression {
             Expression::BlockExpression(e) => write!(f, "{}", e),
             Expression::InvocationExpression(e) => write!(f, "{}", e),
             Expression::Variable(id) => write!(f, "{}", id),
+            Expression::PriorityExpression(e) => write!(f, "({})", e),
         }
     }
 }

src/tokenizer/token.rs

@@ -148,13 +148,6 @@ impl Symbol {
             _ => false,
         }
     }
-
-    pub fn is_assignment(&self) -> bool {
-        match self {
-            Symbol::Assign => true,
-            _ => false,
-        }
-    }
 }
 
 #[derive(Debug, PartialEq, Hash, Eq, Clone, Copy)]