rust_compiler/libs/parser/src/lib.rs

@@ -441,7 +441,13 @@ impl<'a> Parser<'a> {
                 ));
             }
 
-            TokenType::Keyword(Keyword::Let) => Some(self.spanned(|p| p.declaration())?),
+            TokenType::Keyword(Keyword::Let) => {
+                if self_matches_peek!(self, TokenType::Symbol(Symbol::LParen)) {
+                    Some(self.spanned(|p| p.tuple_declaration())?)
+                } else {
+                    Some(self.spanned(|p| p.declaration())?)
+                }
+            }
 
             TokenType::Keyword(Keyword::Device) => {
                 let spanned_dev = self.spanned(|p| p.device())?;
@@ -561,9 +567,7 @@ impl<'a> Parser<'a> {
                 })
             }
 
-            TokenType::Symbol(Symbol::LParen) => {
-                self.spanned(|p| p.priority())?.node.map(|node| *node)
-            }
+            TokenType::Symbol(Symbol::LParen) => self.parenthesized_or_tuple()?,
 
             TokenType::Symbol(Symbol::Minus) => {
                 let start_span = self.current_span();
@@ -642,8 +646,8 @@ impl<'a> Parser<'a> {
                 }
             }
             TokenType::Symbol(Symbol::LParen) => *self
-                .spanned(|p| p.priority())?
-                .node
+                .parenthesized_or_tuple()?
+                .map(Box::new)
                 .ok_or(Error::UnexpectedEOF)?,
 
             TokenType::Identifier(ref id) if SysCall::is_syscall(id) => {
@@ -774,7 +778,8 @@ impl<'a> Parser<'a> {
             | Expression::Ternary(_)
             | Expression::Negation(_)
             | Expression::MemberAccess(_)
-            | Expression::MethodCall(_) => {}
+            | Expression::MethodCall(_)
+            | Expression::Tuple(_) => {}
             _ => {
                 return Err(Error::InvalidSyntax(
                     self.current_span(),
@@ -1117,8 +1122,12 @@ impl<'a> Parser<'a> {
         expressions.pop().ok_or(Error::UnexpectedEOF)
     }
 
-    fn priority(&mut self) -> Result<Option<Box<Spanned<Expression<'a>>>>, Error<'a>> {
+    fn parenthesized_or_tuple(
+        &mut self,
+    ) -> Result<Option<Spanned<tree_node::Expression<'a>>>, Error<'a>> {
+        let start_span = self.current_span();
         let current_token = self.current_token.as_ref().ok_or(Error::UnexpectedEOF)?;
+
         if !token_matches!(current_token, TokenType::Symbol(Symbol::LParen)) {
             return Err(Error::UnexpectedToken(
                 self.current_span(),
@@ -1127,17 +1136,113 @@ impl<'a> Parser<'a> {
         }
 
         self.assign_next()?;
-        let expression = self.expression()?.ok_or(Error::UnexpectedEOF)?;
 
-        let current_token = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
-        if !token_matches!(current_token, TokenType::Symbol(Symbol::RParen)) {
-            return Err(Error::UnexpectedToken(
-                Self::token_to_span(&current_token),
-                current_token,
-            ));
+        // Handle empty tuple '()'
+        if self_matches_peek!(self, TokenType::Symbol(Symbol::RParen)) {
+            self.assign_next()?;
+            let end_span = self.current_span();
+            let span = Span {
+                start_line: start_span.start_line,
+                start_col: start_span.start_col,
+                end_line: end_span.end_line,
+                end_col: end_span.end_col,
+            };
+            return Ok(Some(Spanned {
+                span,
+                node: Expression::Tuple(Spanned { span, node: vec![] }),
+            }));
         }
 
-        Ok(Some(boxed!(expression)))
+        let first_expression = self.expression()?.ok_or(Error::UnexpectedEOF)?;
+
+        if self_matches_peek!(self, TokenType::Symbol(Symbol::Comma)) {
+            // It is a tuple
+            let mut items = vec![first_expression];
+            while self_matches_peek!(self, TokenType::Symbol(Symbol::Comma)) {
+                // Next toekn is a comma, we need to consume it and advance 1 more time.
+                self.assign_next()?;
+                self.assign_next()?;
+                println!("{:?}", self.current_token);
+                items.push(self.expression()?.ok_or(Error::UnexpectedEOF)?);
+            }
+
+            let next = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+            if !token_matches!(next, TokenType::Symbol(Symbol::RParen)) {
+                return Err(Error::UnexpectedToken(Self::token_to_span(&next), next));
+            }
+
+            let end_span = Self::token_to_span(&next);
+            let span = Span {
+                start_line: start_span.start_line,
+                start_col: start_span.start_col,
+                end_line: end_span.end_line,
+                end_col: end_span.end_col,
+            };
+
+            Ok(Some(Spanned {
+                span,
+                node: Expression::Tuple(Spanned { span, node: items }),
+            }))
+        } else {
+            // It is just priority
+            let next = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+            if !token_matches!(next, TokenType::Symbol(Symbol::RParen)) {
+                return Err(Error::UnexpectedToken(Self::token_to_span(&next), next));
+            }
+
+            Ok(Some(Spanned {
+                span: first_expression.span,
+                node: Expression::Priority(boxed!(first_expression)),
+            }))
+        }
+    }
+
+    fn tuple_declaration(&mut self) -> Result<Expression<'a>, Error<'a>> {
+        // 'let' is consumed before this call
+        // expect '('
+        let next = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+        if !token_matches!(next, TokenType::Symbol(Symbol::LParen)) {
+            return Err(Error::UnexpectedToken(Self::token_to_span(&next), next));
+        }
+
+        let mut names = Vec::new();
+        while !self_matches_peek!(self, TokenType::Symbol(Symbol::RParen)) {
+            let token = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+            let span = Self::token_to_span(&token);
+            if let TokenType::Identifier(id) = token.token_type {
+                names.push(Spanned { span, node: id });
+            } else {
+                return Err(Error::UnexpectedToken(span, token));
+            }
+
+            if self_matches_peek!(self, TokenType::Symbol(Symbol::Comma)) {
+                self.assign_next()?;
+            }
+        }
+        self.assign_next()?; // consume ')'
+
+        let assign = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+
+        if !token_matches!(assign, TokenType::Symbol(Symbol::Assign)) {
+            return Err(Error::UnexpectedToken(Self::token_to_span(&assign), assign));
+        }
+
+        self.assign_next()?; // Consume the `=`
+
+        let value = self.expression()?.ok_or(Error::UnexpectedEOF)?;
+
+        let semi = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+        if !token_matches!(semi, TokenType::Symbol(Symbol::Semicolon)) {
+            return Err(Error::UnexpectedToken(Self::token_to_span(&semi), semi));
+        }
+
+        Ok(Expression::TupleDeclaration(Spanned {
+            span: names.first().map(|n| n.span).unwrap_or(value.span),
+            node: TupleDeclarationExpression {
+                names,
+                value: boxed!(value),
+            },
+        }))
     }
 
     fn invocation(&mut self) -> Result<InvocationExpression<'a>, Error<'a>> {

rust_compiler/libs/parser/src/test/mod.rs

@@ -112,7 +112,7 @@ fn test_function_invocation() -> Result<()> {
 #[test]
 fn test_priority_expression() -> Result<()> {
     let input = r#"
-            let x = (4);
+            let x = (4 + 3);
         "#;
 
     let tokenizer = Tokenizer::from(input);
@@ -120,7 +120,7 @@ fn test_priority_expression() -> Result<()> {
 
     let expression = parser.parse()?.unwrap();
 
-    assert_eq!("(let x = 4)", expression.to_string());
+    assert_eq!("(let x = ((4 + 3)))", expression.to_string());
 
     Ok(())
 }
@@ -137,7 +137,7 @@ fn test_binary_expression() -> Result<()> {
     assert_eq!("(((45 * 2) - (15 / 5)) + (5 ** 2))", expr.to_string());
 
     let expr = parser!("(5 - 2) * 10;").parse()?.unwrap();
-    assert_eq!("((5 - 2) * 10)", expr.to_string());
+    assert_eq!("(((5 - 2)) * 10)", expr.to_string());
 
     Ok(())
 }
@@ -170,7 +170,7 @@ fn test_ternary_expression() -> Result<()> {
 fn test_complex_binary_with_ternary() -> Result<()> {
     let expr = parser!("let i = (x ? 1 : 3) * 2;").parse()?.unwrap();
 
-    assert_eq!("(let i = ((x ? 1 : 3) * 2))", expr.to_string());
+    assert_eq!("(let i = (((x ? 1 : 3)) * 2))", expr.to_string());
 
     Ok(())
 }
@@ -191,3 +191,12 @@ fn test_nested_ternary_right_associativity() -> Result<()> {
     assert_eq!("(let i = (a ? b : (c ? d : e)))", expr.to_string());
     Ok(())
 }
+
+#[test]
+fn test_tuple_declaration() -> Result<()> {
+    let expr = parser!("let (x, _) = (1, 2);").parse()?.unwrap();
+
+    assert_eq!("(let (x, _) = (1, 2))", expr.to_string());
+
+    Ok(())
+}

rust_compiler/libs/parser/src/tree_node.rs

@@ -245,6 +245,24 @@ impl<'a> std::fmt::Display for DeviceDeclarationExpression<'a> {
     }
 }
 
+#[derive(Debug, PartialEq, Eq)]
+pub struct TupleDeclarationExpression<'a> {
+    pub names: Vec<Spanned<Cow<'a, str>>>,
+    pub value: Box<Spanned<Expression<'a>>>,
+}
+
+impl<'a> std::fmt::Display for TupleDeclarationExpression<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let names = self
+            .names
+            .iter()
+            .map(|n| n.node.to_string())
+            .collect::<Vec<_>>()
+            .join(", ");
+        write!(f, "(let ({}) = {})", names, self.value)
+    }
+}
+
 #[derive(Debug, PartialEq, Eq)]
 pub struct IfExpression<'a> {
     pub condition: Box<Spanned<Expression<'a>>>,
@@ -348,6 +366,8 @@ pub enum Expression<'a> {
     Return(Option<Box<Spanned<Expression<'a>>>>),
     Syscall(Spanned<SysCall<'a>>),
     Ternary(Spanned<TernaryExpression<'a>>),
+    Tuple(Spanned<Vec<Spanned<Expression<'a>>>>),
+    TupleDeclaration(Spanned<TupleDeclarationExpression<'a>>),
     Variable(Spanned<Cow<'a, str>>),
     While(Spanned<WhileExpression<'a>>),
 }
@@ -384,8 +404,19 @@ impl<'a> std::fmt::Display for Expression<'a> {
             ),
             Expression::Syscall(e) => write!(f, "{}", e),
             Expression::Ternary(e) => write!(f, "{}", e),
+            Expression::Tuple(e) => {
+                let items = e
+                    .node
+                    .iter()
+                    .map(|x| x.to_string())
+                    .collect::<Vec<_>>()
+                    .join(", ");
+                write!(f, "({})", items)
+            }
+            Expression::TupleDeclaration(e) => write!(f, "{}", e),
             Expression::Variable(id) => write!(f, "{}", id),
             Expression::While(e) => write!(f, "{}", e),
         }
     }
 }
+